fix audio blips when should be silent

fix

.gitignore

@@ -1 +1,6 @@
 /target
+*.uf2
+userlib_sys.h
+assets/gif/bad_apple.gif
+picolibc
+user-apps/gboy/Peanut-GB

.gitmodules

@@ -0,0 +1,6 @@
+[submodule "picolibc"]
+	path = picolibc
+	url = https://github.com/picolibc/picolibc
+[submodule "user-apps/gboy/Peanut-GB"]
+	path = user-apps/gboy/Peanut-GB
+	url = https://github.com/deltabeard/Peanut-GB

.helix/languages.toml

@@ -0,0 +1,5 @@
+[[language]]
+name = "rust"
+
+[language-server.rust-analyzer.config.check]
+allTargets = false

Cargo.toml

@@ -1,6 +1,16 @@
 [workspace]
 resolver = "3"
-members = ["kernel", "abi", "shared", "user-apps/calculator"]
+members = [
+  "kernel",
+  "userlib_sys",
+  "userlib",
+  "selection_ui",
+  "user_apps/calculator",
+  "user_apps/snake",
+  "user_apps/gallery",
+  "user_apps/gif",
+  "user_apps/wav_player",
+]
 
 [profile.release]
 debug = true
@@ -10,10 +20,12 @@ codegen-units = 1
 
 [profile.release-binary]
 inherits = "release"
+codegen-units = 1
 lto = true
 debug = false
-opt-level = "s"
+opt-level = "z"
+panic = "unwind"
 
 [profile.dev]
 lto = true
-opt-level = "z"
+opt-level = "s"

README.md

@@ -0,0 +1,35 @@
+# PicoCalc OS (Rust)
+
+A simple kernel and applications for the **Clockwork PicoCalc**, written in Rust.  
+This project provides a minimal kernel, syscall table, and user-space applications to experiment with kernel development on constrained hardware.
+
+## Status
+
+Basic synchronous applications are working great.  
+Current focus is on exanding applications and porting software, finding bugs in ffi, and making sure the kernel is as stable as possible.
+
+## Project Structure
+
+- **`kernel/`** – The core OS kernel
+- **`userlib_sys/`** – C FFI bindings for kernel syscall
+- **`userlib/`** – Rust wrapper on top of `userlib_sys` 
+- **`picolib/`** – Built with ```just newlib```, and provides libc symbols when linking with C libraries 
+- **`user-apps/`** – Collection of userspace programs (gif player, wav player, calculator, snake, etc.)
+
+## Features
+
+- Minimal Rust-based kernel targeting the PicoCalc
+- Custom ABI for *Mostly* safe communication between kernel and applications
+- Support for multiple user-space applications
+- Hardware drivers tailored for the PicoCalc( Audio, Display, Keyboard, ans Storage )
+
+## Getting Started
+
+```bash
+git clone https://github.com/LegitCamper/picocalc-os-rs.git
+cd picocalc-os-rs
+just userapps
+# copy the build applications from target/thumbv8m.main-none-eabihf/release-binary/application to the sdcard and rename them to app.bin
+
+# has builds for the official rp2350 board and the pimoroni2w board
+just kernel-release rp235x # keep in mind that https://github.com/StripedMonkey/elf2uf2-rs version is required until https://github.com/JoNil/elf2uf2-rs/pull/41 is merged

abi/Cargo.toml

@@ -1,12 +0,0 @@
-[package]
-name = "abi"
-version = "0.1.0"
-edition = "2024"
-
-[dependencies]
-embedded-graphics = "0.8.1"
-shared = { path = "../shared" }
-abi_sys = { path = "../abi_sys" }
-talc = "4.4.3"
-spin = "0.10.0"
-embassy-time = "0.5.0"

abi/src/lib.rs

@@ -1,74 +0,0 @@
-#![no_std]
-
-use abi_sys::draw_iter;
-pub use abi_sys::{get_key, print, sleep};
-pub use embassy_time;
-pub use shared::keyboard::{KeyCode, KeyEvent, KeyState, Modifiers};
-use talc::*;
-
-static mut ARENA: [u8; 10000] = [0; 10000];
-
-#[global_allocator]
-static ALLOCATOR: Talck<spin::Mutex<()>, ClaimOnOom> =
-    Talc::new(unsafe { ClaimOnOom::new(Span::from_array(core::ptr::addr_of!(ARENA).cast_mut())) })
-        .lock();
-
-pub mod display {
-    use crate::draw_iter;
-    use embedded_graphics::{
-        Pixel,
-        geometry::{Dimensions, Point},
-        pixelcolor::{Rgb565, RgbColor},
-        prelude::{DrawTarget, Size},
-        primitives::Rectangle,
-    };
-
-    pub const SCREEN_WIDTH: usize = 320;
-    pub const SCREEN_HEIGHT: usize = 320;
-
-    pub type Pixel565 = Pixel<Rgb565>;
-
-    pub struct Display;
-
-    impl Dimensions for Display {
-        fn bounding_box(&self) -> Rectangle {
-            Rectangle {
-                top_left: Point { x: 0, y: 0 },
-                size: Size {
-                    width: SCREEN_WIDTH as u32,
-                    height: SCREEN_HEIGHT as u32,
-                },
-            }
-        }
-    }
-
-    impl DrawTarget for Display {
-        type Color = Rgb565;
-        type Error = ();
-
-        fn draw_iter<I>(&mut self, pixels: I) -> Result<(), Self::Error>
-        where
-            I: IntoIterator<Item = Pixel<Self::Color>>,
-        {
-            const BUF_SIZE: usize = 1024; // tune this for performance
-            let mut buf: [Pixel565; BUF_SIZE] = [Pixel(Point::new(0, 0), Rgb565::BLACK); BUF_SIZE];
-
-            let mut count = 0;
-            for p in pixels {
-                buf[count] = p;
-                count += 1;
-
-                if count == BUF_SIZE {
-                    draw_iter(&buf[..count]);
-                    count = 0;
-                }
-            }
-
-            if count > 0 {
-                draw_iter(&buf[..count]);
-            }
-
-            Ok(())
-        }
-    }
-}

abi_sys/src/lib.rs

@@ -1,71 +0,0 @@
-#![no_std]
-
-extern crate alloc;
-use alloc::boxed::Box;
-
-use core::pin::Pin;
-pub use embedded_graphics::{
-    Pixel,
-    geometry::Point,
-    pixelcolor::{Rgb565, RgbColor},
-};
-use shared::keyboard::{KeyCode, KeyEvent, KeyState, Modifiers};
-
-pub type EntryFn = fn() -> Pin<Box<dyn Future<Output = ()>>>;
-
-#[unsafe(no_mangle)]
-#[unsafe(link_section = ".user_reloc")]
-pub static mut CALL_ABI_TABLE: [usize; CallAbiTable::COUNT] = [0; CallAbiTable::COUNT];
-
-#[repr(usize)]
-#[derive(Clone, Copy)]
-pub enum CallAbiTable {
-    Print = 0,
-    Sleep = 1,
-    DrawIter = 2,
-    GetKey = 3,
-}
-
-impl CallAbiTable {
-    pub const COUNT: usize = 4;
-}
-
-pub type PrintAbi = extern "Rust" fn(msg: &str);
-
-pub fn print(msg: &str) {
-    unsafe {
-        let ptr = CALL_ABI_TABLE[CallAbiTable::Print as usize];
-        let f: PrintAbi = core::mem::transmute(ptr);
-        f(msg);
-    }
-}
-
-pub type SleepAbi = extern "Rust" fn(ms: u64);
-
-pub fn sleep(ms: u64) {
-    unsafe {
-        let ptr = CALL_ABI_TABLE[CallAbiTable::Sleep as usize];
-        let f: SleepAbi = core::mem::transmute(ptr);
-        f(ms);
-    }
-}
-
-pub type DrawIterAbi = extern "Rust" fn(pixels: &[Pixel<Rgb565>]);
-
-pub fn draw_iter(pixels: &[Pixel<Rgb565>]) {
-    unsafe {
-        let ptr = CALL_ABI_TABLE[CallAbiTable::DrawIter as usize];
-        let f: DrawIterAbi = core::mem::transmute(ptr);
-        f(pixels);
-    }
-}
-
-pub type GetKeyAbi = extern "Rust" fn() -> Option<KeyEvent>;
-
-pub fn get_key() -> Option<KeyEvent> {
-    unsafe {
-        let ptr = CALL_ABI_TABLE[CallAbiTable::GetKey as usize];
-        let f: GetKeyAbi = core::mem::transmute(ptr);
-        f()
-    }
-}

cbindgen.toml

@@ -0,0 +1,4 @@
+language = "C"
+
+[macro_expansion]
+bitflags = true

justfile

@@ -1,4 +1,60 @@
-kernel: calculator
+target := "thumbv8m.main-none-eabihf"
-    cargo run --bin kernel
+
-calculator:
+kernel-dev board:
-    RUSTFLAGS="-C link-arg=--noinhibit-exec" cargo build --bin calculator --profile release-binary
+    cargo run --bin kernel --features {{board}}  --features fps --features defmt
+kernel-release-probe board:
+    cargo run --bin kernel --profile release --features {{board}} --features fps
+kernel-release board:
+    cargo build --bin kernel --release --no-default-features --features {{board}}
+    elf2uf2-rs -d target/{{target}}/release/kernel
+
+binary-args := "RUSTFLAGS=\"-C link-arg=-pie -C relocation-model=pic\""
+
+cbindgen:
+    cbindgen userlib_sys --output userlib_sys.h -q
+
+newlib:
+    #!/bin/bash
+    cd picolibc
+    mkdir build
+    cd build
+    CONFIG_PICOLIBC=true ../scripts/do-configure thumbv8m_main_fp-none-eabi \
+        --buildtype=minsize \
+        -Dtests=true \
+        -Dtinystdio=false \
+        -Dsingle-thread=true \
+        -Db_pie=true \
+        -Ddefault_library=static \
+        -Dtinystdio=false \
+        -Dnewlib-nano-malloc=true \
+        -Dmultilib=false \
+        -Dpicolib=true \
+        "$@" 
+    DESTDIR=./install meson install
+    ninja
+
+userapp app:
+     {{binary-args}} cargo build --bin {{app}} --profile release-binary
+
+userapps: cbindgen
+    just userapp calculator
+    just userapp snake
+    just userapp gallery
+    just userapp gif
+    just userapp wav_player
+
+copy-userapp app:
+    cp ./target/{{target}}/release-binary/{{app}} /run/media/$(whoami)/PICOCALC/{{app}}.bin
+
+copy-userapps:
+    #!/bin/bash
+    just userapps
+    just copy-userapp calculator
+    just copy-userapp snake
+    just copy-userapp gallery
+    just copy-userapp gif
+    just copy-userapp wav_player
+
+    DEV=$(lsblk -o LABEL,NAME -nr | awk -v L="PICOCALC" '$1==L {print "/dev/" $2}')
+    udisksctl unmount -b "$DEV"
+    udisksctl power-off -b "$DEV"    

kernel/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "kernel"
-version = "0.1.0"
+version = "0.0.1"
 edition = "2024"
 
 [[bin]]
@@ -11,10 +11,14 @@ doctest = false
 bench = false
 
 [features]
-default = ["rp235x", "defmt"]
+default = ["rp235x"]
-rp2040 = ["embassy-rp/rp2040"]
+pimoroni2w = ["rp235x", "psram"]
+# rp2040 = ["embassy-rp/rp2040"] # unsupported, ram too small for fb
 rp235x = ["embassy-rp/rp235xb"]
 trouble = ["dep:bt-hci", "dep:cyw43", "dep:cyw43-pio", "dep:trouble-host"]
+psram = ["dep:embedded-alloc"]
+overclock = []
+fps = []
 defmt = [
   "dep:defmt",
   "panic-probe/print-defmt",
@@ -45,7 +49,7 @@ embassy-rp = { version = "0.8.0", features = [
 embassy-usb = "0.5.1"
 embassy-futures = "0.1.2"
 embassy-time = { version = "0.5.0", features = ["generic-queue-8"] }
-embassy-embedded-hal = "0.3.1"
+embassy-embedded-hal = "0.3.2"
 embassy-sync = { version = "0.7" }
 trouble-host = { version = "0.1", features = [
   "derive",
@@ -58,6 +62,7 @@ cyw43 = { version = "0.3.0", features = [
 ], optional = true }
 cyw43-pio = { version = "0.3.0", optional = true }
 
+critical-section = "1.2.0"
 embedded-hal-bus = { version = "0.3.0", features = ["async"] }
 embedded-hal = "0.2.7"
 embedded-hal_2 = { package = "embedded-hal", version = "1.0.0" }
@@ -68,22 +73,30 @@ panic-probe = "0.3"
 portable-atomic = { version = "1.11", features = ["critical-section"] }
 assign-resources = "0.5.0"
 
-defmt = { version = "0.3", optional = true }
+defmt = { version = "1.0.1", optional = true }
-defmt-rtt = "0.4.2"
+defmt-rtt = "1.1.0"
 
 embedded-sdmmc = { version = "0.9", default-features = false }
-st7365p-lcd = { git = "https://github.com/legitcamper/st7365p-lcd-rs", rev = "1d15123929fa7ef73d5d6aead7faf1bba50ce915" } # async branch
+st7365p-lcd = { git = "https://github.com/legitcamper/st7365p-lcd-rs", rev = "a784b9e6df0769371dfc522528e770cf8fc6403a" } # async branch
 embedded-graphics = { version = "0.8.1" }
 embedded-text = "0.7.2"
 embedded-layout = "0.4.2"
 
+micromath = "2.1.0"
+fixed = "1.29.0"
+strum = { version = "0.27.2", default-features = false }
+rand = { version = "0.9.0", default-features = false }
+once_cell = { version = "1.21.3", default-features = false }
 static_cell = "2.1.1"
-bitflags = "2.9.1"
+bitflags = "2.9.4"
 heapless = "0.8.0"
-num_enum = { version = "0.7.4", default-features = false }
-goblin = { version = "0.10.0", default-features = false, features = ["elf32"] }
-talc = "4.4.3"
 spin = "0.10.0"
+num_enum = { version = "0.7.4", default-features = false }
+goblin = { version = "0.10.1", default-features = false, features = ["elf32"] }
+talc = "4.4.3"
+embedded-alloc = { version = "0.6.0", features = [
+  "allocator_api",
+], optional = true }
+bumpalo = "3.19.0"
 
-shared = { path = "../shared" }
+userlib_sys = { path = "../userlib_sys" }
-abi_sys = { path = "../abi_sys" }

kernel/build.rs

@@ -13,13 +13,18 @@ use std::fs::File;
 use std::io::Write;
 use std::path::PathBuf;
 
+#[cfg(all(feature = "rp235x", not(feature = "pimoroni2w")))]
+const MEMORY: &[u8] = include_bytes!("rp2350.x");
+#[cfg(feature = "pimoroni2w")]
+const MEMORY: &'static [u8] = include_bytes!("rp2350.x");
+
 fn main() {
     // Put `memory.x` in our output directory and ensure it's
     // on the linker search path.
     let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
     File::create(out.join("memory.x"))
         .unwrap()
-        .write_all(include_bytes!("memory.x"))
+        .write_all(MEMORY)
         .unwrap();
     println!("cargo:rustc-link-search={}", out.display());
 

kernel/pimoroni2w.x

@@ -0,0 +1,60 @@
+MEMORY {
+    FLASH : ORIGIN = 0x10000000, LENGTH = 16M - 4K
+
+    RAM : ORIGIN = 0x20000000, LENGTH = 512K
+    # SRAM4 : ORIGIN = 0x20080000, LENGTH = 4K
+    SRAM5 : ORIGIN = 0x20081000, LENGTH = 4K
+}
+
+SECTIONS {
+    /* ### Boot ROM info
+     *
+     * Goes after .vector_table, to keep it in the first 4K of flash
+     * where the Boot ROM (and picotool) can find it
+     */
+    .start_block : ALIGN(4)
+    {
+        __start_block_addr = .;
+        KEEP(*(.start_block));
+        KEEP(*(.boot_info));
+    } > FLASH
+
+} INSERT AFTER .vector_table;
+
+/* move .text to start /after/ the boot info */
+_stext = ADDR(.start_block) + SIZEOF(.start_block);
+
+SECTIONS {
+    /* ### Picotool 'Binary Info' Entries
+     *
+     * Picotool looks through this block (as we have pointers to it in our
+     * header) to find interesting information.
+     */
+    .bi_entries : ALIGN(4)
+    {
+        /* We put this in the header */
+        __bi_entries_start = .;
+        /* Here are the entries */
+        KEEP(*(.bi_entries));
+        /* Keep this block a nice round size */
+        . = ALIGN(4);
+        /* We put this in the header */
+        __bi_entries_end = .;
+    } > FLASH
+} INSERT AFTER .text;
+
+SECTIONS {
+    /* ### Boot ROM extra info
+     *
+     * Goes after everything in our program, so it can contain a signature.
+     */
+    .end_block : ALIGN(4)
+    {
+        __end_block_addr = .;
+        KEEP(*(.end_block));
+    } > FLASH
+
+} INSERT AFTER .uninit;
+
+PROVIDE(start_to_end = __end_block_addr - __start_block_addr);
+PROVIDE(end_to_start = __start_block_addr - __end_block_addr);

kernel/rp2350.x

@@ -1,10 +1,7 @@
 MEMORY {
     FLASH : ORIGIN = 0x10000000, LENGTH = 4096K
+
     RAM : ORIGIN = 0x20000000, LENGTH = 512K
-
-	/* Reserve a block of RAM for the user app */
-    USERAPP : ORIGIN = 0x20010000, LENGTH = 192K
-
     SRAM4 : ORIGIN = 0x20080000, LENGTH = 4K
     SRAM5 : ORIGIN = 0x20081000, LENGTH = 4K
 }
@@ -61,11 +58,3 @@ SECTIONS {
 
 PROVIDE(start_to_end = __end_block_addr - __start_block_addr);
 PROVIDE(end_to_start = __start_block_addr - __end_block_addr);
-
-SECTIONS {
-	.userapp (NOLOAD) :
-	{
-	    __userapp_start__ = ORIGIN(USERAPP);
-	    __userapp_end__   = ORIGIN(USERAPP) + LENGTH(USERAPP);
-	} > USERAPP
-}

kernel/src/abi.rs

@@ -1,46 +0,0 @@
-use core::{pin::Pin, time::Duration};
-
-use abi_sys::{DrawIterAbi, GetKeyAbi, Pixel, PrintAbi, SleepAbi};
-use alloc::boxed::Box;
-use defmt::info;
-use embassy_futures::block_on;
-use embassy_rp::clocks::clk_sys_freq;
-use embassy_time::Timer;
-use embedded_graphics::{
-    Drawable,
-    draw_target::DrawTarget,
-    pixelcolor::Rgb565,
-    prelude::{Point, RgbColor, Size},
-    primitives::{PrimitiveStyle, Rectangle, StyledDrawable},
-};
-use shared::keyboard::KeyEvent;
-
-use crate::{KEY_CACHE, display::FRAMEBUFFER};
-
-// ensure the abi and the kernel fn signatures are the same
-const _: PrintAbi = print;
-const _: SleepAbi = sleep;
-const _: DrawIterAbi = draw_iter;
-const _: GetKeyAbi = get_key;
-
-pub extern "Rust" fn print(msg: &str) {
-    defmt::info!("{:?}", msg);
-}
-
-pub extern "Rust" fn sleep(ms: u64) {
-    let cycles_per_ms = clk_sys_freq() / 1000;
-    for _ in 0..ms {
-        for _ in 0..cycles_per_ms {
-            cortex_m::asm::nop();
-        }
-    }
-}
-
-// TODO: maybe return result
-pub extern "Rust" fn draw_iter(pixels: &[Pixel<Rgb565>]) {
-    unsafe { FRAMEBUFFER.draw_iter(pixels.iter().copied()).unwrap() }
-}
-
-pub extern "Rust" fn get_key() -> Option<KeyEvent> {
-    unsafe { KEY_CACHE.dequeue() }
-}

kernel/src/audio.rs

@@ -0,0 +1,174 @@
+use crate::Audio;
+use core::sync::atomic::{AtomicBool, Ordering};
+use embassy_futures::{join::join, yield_now};
+use embassy_rp::{
+    Peri,
+    clocks::clk_sys_freq,
+    dma::{AnyChannel, Channel},
+    gpio::Level,
+    pio::{
+        Common, Config, Direction, FifoJoin, Instance, LoadedProgram, PioPin, ShiftConfig,
+        StateMachine, program::pio_asm,
+    },
+};
+use fixed::traits::ToFixed;
+
+pub const SAMPLE_RATE_HZ: u32 = 22_050;
+const AUDIO_BUFFER_SAMPLES: usize = 1024;
+const _: () = assert!(AUDIO_BUFFER_SAMPLES == userlib_sys::AUDIO_BUFFER_SAMPLES);
+
+const SILENCE: u8 = u8::MAX / 2;
+
+// 8bit stereo interleaved PCM audio buffers
+pub static mut AUDIO_BUFFER: [u8; AUDIO_BUFFER_SAMPLES * 2] = [SILENCE; AUDIO_BUFFER_SAMPLES * 2];
+static mut AUDIO_BUFFER_1: [u8; AUDIO_BUFFER_SAMPLES * 2] = [SILENCE; AUDIO_BUFFER_SAMPLES * 2];
+
+pub static AUDIO_BUFFER_READY: AtomicBool = AtomicBool::new(true);
+pub static AUDIO_BUFFER_WRITTEN: AtomicBool = AtomicBool::new(false);
+
+pub fn clear_audio_buffers() {
+    unsafe {
+        AUDIO_BUFFER.fill(SILENCE);
+        AUDIO_BUFFER_1.fill(SILENCE);
+    }
+}
+
+#[embassy_executor::task]
+pub async fn audio_handler(mut audio: Audio) {
+    let prg = PioPwmAudioProgram8Bit::new(&mut audio.pio);
+    let mut pwm_pio_left =
+        PioPwmAudio::new(audio.dma0, &mut audio.pio, audio.sm0, audio.left, &prg);
+    let mut pwm_pio_right =
+        PioPwmAudio::new(audio.dma1, &mut audio.pio, audio.sm1, audio.right, &prg);
+
+    loop {
+        unsafe {
+            if AUDIO_BUFFER_WRITTEN.load(Ordering::Acquire) {
+                write_samples(&mut pwm_pio_left, &mut pwm_pio_right, &AUDIO_BUFFER_1).await;
+                AUDIO_BUFFER_1.fill(SILENCE);
+                core::mem::swap(&mut AUDIO_BUFFER, &mut AUDIO_BUFFER_1);
+                AUDIO_BUFFER_READY.store(true, Ordering::Release)
+            } else {
+                yield_now().await;
+            }
+        }
+    }
+}
+
+async fn write_samples<PIO: Instance>(
+    left: &mut PioPwmAudio<'static, PIO, 0>,
+    right: &mut PioPwmAudio<'static, PIO, 1>,
+    buf: &[u8],
+) {
+    // pack two samples per word
+    static mut PACKED_BUF_L: [u32; AUDIO_BUFFER_SAMPLES / 2] = [0; AUDIO_BUFFER_SAMPLES / 2];
+    static mut PACKED_BUF_R: [u32; AUDIO_BUFFER_SAMPLES / 2] = [0; AUDIO_BUFFER_SAMPLES / 2];
+
+    unsafe {
+        for ((pl, pr), sample) in PACKED_BUF_L
+            .iter_mut()
+            .zip(PACKED_BUF_R.iter_mut())
+            .zip(buf.chunks(4))
+        {
+            *pl = pack_u8_samples(sample[0], sample[2]);
+            *pr = pack_u8_samples(sample[1], sample[3]);
+        }
+
+        let left_fut = left
+            .sm
+            .tx()
+            .dma_push(left.dma.reborrow(), &PACKED_BUF_L, false);
+
+        let right_fut = right
+            .sm
+            .tx()
+            .dma_push(right.dma.reborrow(), &PACKED_BUF_R, false);
+
+        join(left_fut, right_fut).await;
+    }
+}
+
+struct PioPwmAudioProgram8Bit<'d, PIO: Instance>(LoadedProgram<'d, PIO>);
+
+/// Writes one sample to pwm as high and low time
+impl<'d, PIO: Instance> PioPwmAudioProgram8Bit<'d, PIO> {
+    fn new(common: &mut Common<'d, PIO>) -> Self {
+        // only uses 16 bits top for pwm high, bottom for pwm low
+        // allows storing two samples per word
+        let prg = pio_asm!(
+            ".side_set 1",
+
+            "set x, 0 side 1",
+            "set y, 0 side 0",
+            ".wrap_target",
+
+            "check:",
+            "pull ifempty noblock side 1", // gets new osr or loads 0 into x, gets second sample if osr not empty
+            "out x, 8 side 0", // pwm high time
+            "out y, 8 side 1", // pwm low time
+            "jmp x!=y play_sample side 0", // x & y are never equal unless osr was empty
+            "set x, 1 side 1",
+            "set y, 1 side 0",
+
+            "play_sample:"
+            "loop_high:",
+            "jmp x-- loop_high side 1", // keep pwm high, decrement X until 0
+            "loop_low:",
+            "jmp y-- loop_low side 0", // keep pwm low, decrement Y until 0
+            ".wrap"
+        );
+
+        let prg = common.load_program(&prg.program);
+
+        Self(prg)
+    }
+}
+
+struct PioPwmAudio<'d, PIO: Instance, const SM: usize> {
+    dma: Peri<'d, AnyChannel>,
+    sm: StateMachine<'d, PIO, SM>,
+}
+
+impl<'d, PIO: Instance, const SM: usize> PioPwmAudio<'d, PIO, SM> {
+    fn new(
+        dma: Peri<'d, impl Channel>,
+        pio: &mut Common<'d, PIO>,
+        mut sm: StateMachine<'d, PIO, SM>,
+        pin: Peri<'d, impl PioPin>,
+        prg: &PioPwmAudioProgram8Bit<'d, PIO>,
+    ) -> Self {
+        let pin = pio.make_pio_pin(pin);
+        sm.set_pins(Level::High, &[&pin]);
+        sm.set_pin_dirs(Direction::Out, &[&pin]);
+
+        let mut cfg = Config::default();
+        cfg.fifo_join = FifoJoin::TxOnly;
+        let shift_cfg = ShiftConfig {
+            auto_fill: false,
+            ..Default::default()
+        };
+        cfg.shift_out = shift_cfg;
+        cfg.use_program(&prg.0, &[&pin]);
+        sm.set_config(&cfg);
+
+        let target_clock = (u8::MAX as u32 + 1) * SAMPLE_RATE_HZ;
+        let divider = (clk_sys_freq() / target_clock).to_fixed();
+        sm.set_clock_divider(divider);
+
+        sm.set_enable(true);
+
+        Self {
+            dma: dma.into(),
+            sm,
+        }
+    }
+}
+
+/// packs two u8 samples into 32bit word
+fn pack_u8_samples(sample1: u8, sample2: u8) -> u32 {
+    (u8_pcm_to_pwm(sample1) as u32) << 16 | u8_pcm_to_pwm(sample2) as u32
+}
+
+fn u8_pcm_to_pwm(sample: u8) -> u16 {
+    ((sample as u16) << 8) | ((u8::MAX - sample) as u16)
+}

kernel/src/display.rs

@@ -1,20 +1,27 @@
-use crate::framebuffer::AtomicFrameBuffer;
+use crate::framebuffer::{self, AtomicFrameBuffer, FB_PAUSED};
+use core::sync::atomic::Ordering;
+use embassy_futures::yield_now;
 use embassy_rp::{
     Peri,
     gpio::{Level, Output},
     peripherals::{PIN_13, PIN_14, PIN_15, SPI1},
     spi::{Async, Spi},
 };
-use embassy_time::{Delay, Timer};
+use embassy_time::Delay;
-use embedded_graphics::{
-    draw_target::DrawTarget,
-    pixelcolor::{Rgb565, RgbColor},
-    prelude::Dimensions,
-};
 use embedded_hal_bus::spi::ExclusiveDevice;
 use st7365p_lcd::ST7365P;
 
-type DISPLAY = ST7365P<
+#[cfg(feature = "psram")]
+use crate::heap::HEAP;
+#[cfg(feature = "psram")]
+use core::alloc::{GlobalAlloc, Layout};
+#[cfg(feature = "psram")]
+use embedded_graphics::{draw_target::DrawTarget, pixelcolor::Rgb565, prelude::RgbColor};
+
+#[cfg(feature = "fps")]
+pub use framebuffer::fps::{FPS_CANVAS, FPS_COUNTER};
+
+type Display = ST7365P<
     ExclusiveDevice<Spi<'static, SPI1, Async>, Output<'static>, Delay>,
     Output<'static>,
     Output<'static>,
@@ -24,14 +31,36 @@ type DISPLAY = ST7365P<
 pub const SCREEN_WIDTH: usize = 320;
 pub const SCREEN_HEIGHT: usize = 320;
 
-pub static mut FRAMEBUFFER: AtomicFrameBuffer = AtomicFrameBuffer::new();
+pub static mut FRAMEBUFFER: Option<AtomicFrameBuffer> = None;
+
+fn init_fb() {
+    unsafe {
+        #[cfg(feature = "psram")]
+        {
+            let slab = HEAP.alloc(Layout::array::<u16>(framebuffer::SIZE).unwrap()) as *mut u16;
+            let buf = core::slice::from_raw_parts_mut(slab, framebuffer::SIZE);
+
+            let mut fb = AtomicFrameBuffer::new(buf);
+            fb.clear(Rgb565::BLACK).unwrap();
+            FRAMEBUFFER = Some(fb);
+        }
+
+        #[cfg(not(feature = "psram"))]
+        {
+            static mut BUF: [u16; framebuffer::SIZE] = [0; framebuffer::SIZE];
+            FRAMEBUFFER = Some(AtomicFrameBuffer::new(&mut BUF));
+        }
+    }
+}
 
 pub async fn init_display(
     spi: Spi<'static, SPI1, Async>,
     cs: Peri<'static, PIN_13>,
     data: Peri<'static, PIN_14>,
     reset: Peri<'static, PIN_15>,
-) -> DISPLAY {
+) -> Display {
+    init_fb();
+
     let spi_device = ExclusiveDevice::new(spi, Output::new(cs, Level::Low), Delay).unwrap();
     let mut display = ST7365P::new(
         spi_device,
@@ -43,28 +72,52 @@ pub async fn init_display(
     );
     display.init().await.unwrap();
     display.set_custom_orientation(0x40).await.unwrap();
-    unsafe { FRAMEBUFFER.draw(&mut display).await.unwrap() }
+    unsafe {
+        FRAMEBUFFER
+            .as_mut()
+            .unwrap()
+            .draw(&mut display)
+            .await
+            .unwrap()
+    }
     display.set_on().await.unwrap();
 
     display
 }
 
-pub fn clear_fb() {
+#[embassy_executor::task]
-    let bounds = unsafe { FRAMEBUFFER.bounding_box() };
+pub async fn display_handler(mut display: Display) {
-    unsafe {
+    use embassy_time::{Instant, Timer};
-        let _ = FRAMEBUFFER.fill_solid(&bounds, Rgb565::BLACK);
+
-    }
+    // Target ~60 Hz refresh (≈16.67 ms per frame)
-}
+    const FRAME_TIME_MS: u64 = 1000 / 60;
 
-pub async fn display_handler(mut display: DISPLAY) {
     loop {
+        let start = Instant::now();
+
+        #[cfg(feature = "fps")]
         unsafe {
-            FRAMEBUFFER
+            if FPS_COUNTER.should_draw() {
-                .partial_draw_batched(&mut display)
+                FPS_CANVAS.draw_fps().await;
-                .await
+            }
-                .unwrap()
         }
 
-        Timer::after_millis(32).await; // 30 fps
+        if !FB_PAUSED.load(Ordering::Acquire) {
+            unsafe {
+                FRAMEBUFFER
+                    .as_mut()
+                    .unwrap()
+                    .partial_draw(&mut display)
+                    .await
+                    .unwrap();
+            }
+        }
+
+        let elapsed = start.elapsed().as_millis();
+        if elapsed < FRAME_TIME_MS {
+            Timer::after_millis(FRAME_TIME_MS - elapsed).await;
+        } else {
+            yield_now().await;
+        }
     }
 }

kernel/src/elf.rs

@@ -1,87 +1,160 @@
-#![allow(static_mut_refs)]
-
 use crate::{
-    abi,
     storage::{File, SDCARD},
+    syscalls,
 };
-use abi_sys::{CallAbiTable, EntryFn};
 use alloc::{vec, vec::Vec};
+use bumpalo::Bump;
+use core::ptr;
 use embedded_sdmmc::ShortFileName;
 use goblin::{
     elf::{
         header::header32::Header,
         program_header::program_header32::{PT_LOAD, ProgramHeader},
-        section_header::SHT_SYMTAB,
+        reloc::R_ARM_RELATIVE,
+        section_header::{SHT_REL, SHT_SYMTAB},
     },
-    elf32::{section_header::SectionHeader, sym::Sym},
+    elf32::{header, reloc::Rel, section_header::SectionHeader, sym::Sym},
 };
+use strum::IntoEnumIterator;
+use userlib_sys::{EntryFn, SyscallTable};
 
 const ELF32_HDR_SIZE: usize = 52;
 
-// userland ram region defined in memory.x
+pub async unsafe fn load_binary(name: &ShortFileName) -> Option<(EntryFn, Bump)> {
-unsafe extern "C" {
-    static __userapp_start__: u8;
-    static __userapp_end__: u8;
-}
-
-pub async unsafe fn load_binary(name: &ShortFileName) -> Result<EntryFn, &str> {
     let mut sd_lock = SDCARD.get().lock().await;
     let sd = sd_lock.as_mut().unwrap();
 
-    let mut error = "";
-    let mut entry = 0;
-
     let mut header_buf = [0; ELF32_HDR_SIZE];
 
-    sd.read_file(name, |mut file| {
+    let (entry, bump) = sd
-        file.read(&mut header_buf).unwrap();
+        .read_file(name, |mut file| {
-        let elf_header = Header::from_bytes(&header_buf);
+            file.read(&mut header_buf).unwrap();
+            let elf_header = Header::from_bytes(&header_buf);
 
-        let mut program_headers_buf = vec![0_u8; elf_header.e_phentsize as usize];
+            // reject non-PIE
-        for i in 1..=elf_header.e_phnum {
+            if elf_header.e_type != header::ET_DYN {
-            file.seek_from_start(elf_header.e_phoff + (elf_header.e_phentsize * i) as u32)
+                return None;
-                .unwrap();
-            file.read(&mut program_headers_buf).unwrap();
-
-            let ph = cast_phdr(&program_headers_buf);
-
-            if ph.p_type == PT_LOAD {
-                load_segment(&mut file, &ph).unwrap()
             }
-        }
 
-        // MUST MATCH ABI EXACTLY
+            let mut ph_buf = vec![0_u8; elf_header.e_phentsize as usize];
-        let entries: &[(CallAbiTable, usize)] = &[
-            (CallAbiTable::Print, abi::print as usize),
-            (CallAbiTable::Sleep, abi::sleep as usize),
-            (CallAbiTable::DrawIter, abi::draw_iter as usize),
-            (CallAbiTable::GetKey, abi::get_key as usize),
-        ];
-        assert!(entries.len() == CallAbiTable::COUNT);
 
-        patch_abi(entries, &elf_header, &mut file).unwrap();
+            let (total_size, min_vaddr, _max_vaddr) =
+                total_loadable_size(&mut file, elf_header, &mut ph_buf);
 
-        // TODO: dynamically search for abi table
+            let bump = Bump::with_capacity(total_size);
+            let base = bump.alloc_slice_fill_default::<u8>(total_size);
 
-        entry = elf_header.e_entry as u32;
+            // load each segment into bump, relative to base_ptr
-    })
+            for i in 0..elf_header.e_phnum {
-    .await
+                file.seek_from_start(elf_header.e_phoff + (elf_header.e_phentsize * i) as u32)
-    .unwrap();
+                    .unwrap();
+                file.read(&mut ph_buf).unwrap();
+                let ph = cast_phdr(&ph_buf);
 
-    if entry != 0 {
+                let seg_offset = (ph.p_vaddr - min_vaddr) as usize;
-        Ok(unsafe { core::mem::transmute(entry) })
+                let segment = &mut base[seg_offset..seg_offset + ph.p_memsz as usize];
-    } else {
+
-        Err(error)
+                if ph.p_type == PT_LOAD {
-    }
+                    load_segment(&mut file, &ph, segment).unwrap();
+                }
+            }
+
+            for i in 0..elf_header.e_shnum {
+                let sh = read_section(&mut file, elf_header, i.into());
+
+                if sh.sh_type == SHT_REL {
+                    apply_relocations(&sh, min_vaddr, base.as_mut_ptr(), &mut file).unwrap();
+                }
+            }
+
+            patch_syscalls(elf_header, base.as_mut_ptr(), min_vaddr, &mut file).unwrap();
+
+            // entry pointer is base_ptr + (entry - min_vaddr)
+            let entry_ptr: EntryFn = unsafe {
+                core::mem::transmute(base.as_ptr().add((elf_header.e_entry - min_vaddr) as usize))
+            };
+
+            Some((entry_ptr, bump))
+        })
+        .await
+        .expect("Failed to read file")?;
+
+    Some((entry, bump))
 }
 
-fn patch_abi(
+fn load_segment(file: &mut File, ph: &ProgramHeader, segment: &mut [u8]) -> Result<(), ()> {
-    entries: &[(CallAbiTable, usize)],
+    let filesz = ph.p_filesz as usize;
+    let memsz = ph.p_memsz as usize;
+
+    // read file contents
+    let mut remaining = filesz;
+    let mut dst_offset = 0;
+    let mut file_offset = ph.p_offset;
+    let mut buf = [0u8; 512];
+
+    while remaining > 0 {
+        let to_read = core::cmp::min(remaining, buf.len());
+        file.seek_from_start(file_offset).unwrap();
+        file.read(&mut buf[..to_read]).unwrap();
+
+        segment[dst_offset..dst_offset + to_read].copy_from_slice(&buf[..to_read]);
+
+        remaining -= to_read;
+        dst_offset += to_read;
+        file_offset += to_read as u32;
+    }
+
+    // zero BSS if needed
+    if memsz > filesz {
+        segment[filesz..].fill(0);
+    }
+
+    Ok(())
+}
+
+fn apply_relocations(
+    sh: &SectionHeader,
+    min_vaddr: u32,
+    base: *mut u8,
+    file: &mut File,
+) -> Result<(), ()> {
+    let mut reloc = [0_u8; 8];
+
+    let num_relocs = sh.sh_size as usize / sh.sh_entsize as usize;
+
+    for i in 0..num_relocs {
+        file.seek_from_start(sh.sh_offset + (i as u32 * 8)).unwrap();
+        file.read(&mut reloc).unwrap();
+
+        let rel = cast_rel(&reloc);
+
+        let reloc_type = rel.r_info & 0xff;
+        let reloc_addr = unsafe { base.add((rel.r_offset - min_vaddr) as usize) as *mut u32 };
+
+        match reloc_type {
+            R_ARM_RELATIVE => {
+                // REL: add base to the word already stored there
+                unsafe {
+                    let val = ptr::read_unaligned(reloc_addr);
+                    ptr::write_unaligned(reloc_addr, val.wrapping_add(base as u32));
+                }
+            }
+            _ => {
+                return Err(());
+            }
+        }
+    }
+    Ok(())
+}
+
+fn patch_syscalls(
     elf_header: &Header,
+    base: *mut u8,
+    min_vaddr: u32,
     file: &mut File,
 ) -> Result<(), ()> {
     for i in 1..=elf_header.e_shnum {
-        let sh = read_section(file, &elf_header, i.into());
+        let sh = read_section(file, elf_header, i.into());
 
         // find the symbol table
         if sh.sh_type == SHT_SYMTAB {
@@ -96,7 +169,7 @@ fn patch_abi(
                     &symtab_buf[i * sh.sh_entsize as usize..(i + 1) * sh.sh_entsize as usize];
                 let sym = cast_sym(sym_bytes);
 
-                let str_sh = read_section(file, &elf_header, sh.sh_link);
+                let str_sh = read_section(file, elf_header, sh.sh_link);
 
                 let mut name = Vec::new();
                 file.seek_from_start(str_sh.sh_offset + sym.st_name)
@@ -112,12 +185,30 @@ fn patch_abi(
                 }
 
                 let symbol_name = core::str::from_utf8(&name).unwrap();
-                if symbol_name == "CALL_ABI_TABLE" {
+                if symbol_name == stringify!(SYS_CALL_TABLE) {
-                    let table_base = sym.st_value as *mut usize;
+                    let table_base =
+                        unsafe { base.add((sym.st_value as usize) - min_vaddr as usize) }
+                            as *mut usize;
 
-                    for &(abi_idx, func_ptr) in entries {
+                    for (idx, call) in SyscallTable::iter().enumerate() {
+                        let ptr = match call {
+                            SyscallTable::Alloc => syscalls::alloc as usize,
+                            SyscallTable::Dealloc => syscalls::dealloc as usize,
+                            SyscallTable::PrintString => syscalls::print as usize,
+                            SyscallTable::SleepMs => syscalls::sleep as usize,
+                            SyscallTable::GetMs => syscalls::get_ms as usize,
+                            SyscallTable::DrawIter => syscalls::draw_iter as usize,
+                            SyscallTable::GetKey => syscalls::get_key as usize,
+                            SyscallTable::GenRand => syscalls::gen_rand as usize,
+                            SyscallTable::ListDir => syscalls::list_dir as usize,
+                            SyscallTable::ReadFile => syscalls::read_file as usize,
+                            SyscallTable::WriteFile => syscalls::write_file as usize,
+                            SyscallTable::FileLen => syscalls::file_len as usize,
+                            SyscallTable::AudioBufferReady => syscalls::audio_buffer_ready as usize,
+                            SyscallTable::SendAudioBuffer => syscalls::send_audio_buffer as usize,
+                        };
                         unsafe {
-                            table_base.add(abi_idx as usize).write(func_ptr);
+                            table_base.add(idx).write(ptr);
                         }
                     }
                     return Ok(());
@@ -128,65 +219,41 @@ fn patch_abi(
     Err(())
 }
 
+fn total_loadable_size(
+    file: &mut File,
+    elf_header: &Header,
+    ph_buf: &mut [u8],
+) -> (usize, u32, u32) {
+    let mut min_vaddr = u32::MAX;
+    let mut max_vaddr = 0u32;
+    for i in 0..elf_header.e_phnum {
+        file.seek_from_start(elf_header.e_phoff + (elf_header.e_phentsize * i) as u32)
+            .unwrap();
+        file.read(ph_buf).unwrap();
+        let ph = cast_phdr(ph_buf);
+
+        if ph.p_type == PT_LOAD {
+            if ph.p_vaddr < min_vaddr {
+                min_vaddr = ph.p_vaddr;
+            }
+            if ph.p_vaddr + ph.p_memsz > max_vaddr {
+                max_vaddr = ph.p_vaddr + ph.p_memsz;
+            }
+        }
+    }
+
+    let total_size = (max_vaddr - min_vaddr) as usize;
+    (total_size, min_vaddr, max_vaddr)
+}
+
 fn read_section(file: &mut File, elf_header: &Header, section: u32) -> SectionHeader {
-    let mut section_header_buf = vec![0_u8; elf_header.e_shentsize as usize];
+    let mut sh_buf = vec![0_u8; elf_header.e_shentsize as usize];
 
     file.seek_from_start(elf_header.e_shoff + (elf_header.e_shentsize as u32 * section))
         .unwrap();
-    file.read(&mut section_header_buf).unwrap();
+    file.read(&mut sh_buf).unwrap();
 
-    cast_shdr(&section_header_buf)
+    cast_shdr(&sh_buf)
-}
-
-fn load_segment(file: &mut File, ph: &ProgramHeader) -> Result<(), ()> {
-    let dst_start = ph.p_vaddr as *mut u8;
-    let filesz = ph.p_filesz as usize;
-    let memsz = ph.p_memsz as usize;
-    let vaddr = ph.p_vaddr as usize;
-    let mut remaining = filesz;
-    let mut dst_ptr = dst_start;
-    let mut file_offset = ph.p_offset;
-
-    let seg_start = vaddr;
-    let seg_end = vaddr + memsz;
-
-    // Bounds check: make sure segment fits inside payload region
-    let user_start = unsafe { &__userapp_start__ as *const u8 as usize };
-    let user_end = unsafe { &__userapp_end__ as *const u8 as usize };
-    if seg_start < user_start || seg_end > user_end {
-        panic!(
-            "Segment out of bounds: {:x}..{:x} not within {:x}..{:x}",
-            seg_start, seg_end, user_start, user_end
-        );
-    }
-
-    // Buffer for chunked reads (512 bytes is typical SD sector size)
-    let mut buf = [0u8; 512];
-
-    while remaining > 0 {
-        let to_read = core::cmp::min(remaining, buf.len());
-        // Read chunk from file
-        file.seek_from_start(file_offset).unwrap();
-        file.read(&mut buf[..to_read]).unwrap();
-
-        unsafe {
-            // Copy chunk directly into destination memory
-            core::ptr::copy_nonoverlapping(buf.as_ptr(), dst_ptr, to_read);
-            dst_ptr = dst_ptr.add(to_read);
-        }
-
-        remaining -= to_read;
-        file_offset += to_read as u32;
-    }
-
-    // Zero BSS (memsz - filesz)
-    if memsz > filesz {
-        unsafe {
-            core::ptr::write_bytes(dst_ptr, 0, memsz - filesz);
-        }
-    }
-
-    Ok(())
 }
 
 fn cast_phdr(buf: &[u8]) -> ProgramHeader {
@@ -203,3 +270,8 @@ fn cast_sym(buf: &[u8]) -> Sym {
     assert!(buf.len() >= core::mem::size_of::<Sym>());
     unsafe { core::ptr::read(buf.as_ptr() as *const Sym) }
 }
+
+fn cast_rel(buf: &[u8]) -> Rel {
+    assert!(buf.len() >= core::mem::size_of::<Rel>());
+    unsafe { core::ptr::read(buf.as_ptr() as *const Rel) }
+}

kernel/src/framebuffer.rs

@@ -1,6 +1,5 @@
 use crate::display::{SCREEN_HEIGHT, SCREEN_WIDTH};
 use core::sync::atomic::{AtomicBool, Ordering};
-use embassy_sync::lazy_lock::LazyLock;
 use embedded_graphics::{
     draw_target::DrawTarget,
     pixelcolor::{
@@ -12,38 +11,42 @@ use embedded_graphics::{
 };
 use embedded_hal_2::digital::OutputPin;
 use embedded_hal_async::{delay::DelayNs, spi::SpiDevice};
-use heapless::Vec;
+use st7365p_lcd::ST7365P;
-use st7365p_lcd::{FrameBuffer, ST7365P};
 
-pub const TILE_SIZE: usize = 16; // 16x16 tile
+#[cfg(feature = "fps")]
-pub const TILE_COUNT: usize = (SCREEN_WIDTH / TILE_SIZE) * (SCREEN_HEIGHT / TILE_SIZE); // 400 tiles
+use fps::{FPS_CANVAS, FPS_CANVAS_HEIGHT, FPS_CANVAS_WIDTH, FPS_CANVAS_X, FPS_CANVAS_Y};
 
-// Group of tiles for batching
+const TILE_SIZE: usize = 16; // 16x16 tile
-pub const MAX_META_TILES: usize = SCREEN_WIDTH / TILE_SIZE; // max number of meta tiles in buffer
+const TILE_COUNT: usize = (SCREEN_WIDTH / TILE_SIZE) * (SCREEN_HEIGHT / TILE_SIZE); // 400 tiles
-type MetaTileVec = heapless::Vec<Rectangle, { TILE_COUNT / MAX_META_TILES }>;
+const NUM_TILE_ROWS: usize = SCREEN_WIDTH / TILE_SIZE;
+const NUM_TILE_COLS: usize = SCREEN_WIDTH / TILE_SIZE;
 
-const SIZE: usize = SCREEN_HEIGHT * SCREEN_WIDTH;
+const MAX_BATCH_TILES: usize = (SCREEN_WIDTH / TILE_SIZE) * 2;
+type BatchTileBuf = [u16; MAX_BATCH_TILES * TILE_SIZE * TILE_SIZE];
 
-static mut BUFFER: [u16; SIZE] = [0; SIZE];
+pub const SIZE: usize = SCREEN_HEIGHT * SCREEN_WIDTH;
 
-static mut DIRTY_TILES: LazyLock<Vec<AtomicBool, TILE_COUNT>> = LazyLock::new(|| {
+pub static FB_PAUSED: AtomicBool = AtomicBool::new(false);
-    let mut tiles = Vec::new();
-    for _ in 0..TILE_COUNT {
-        tiles.push(AtomicBool::new(true)).unwrap();
-    }
-    tiles
-});
 
 #[allow(dead_code)]
-pub struct AtomicFrameBuffer;
+pub struct AtomicFrameBuffer<'a> {
+    fb: &'a mut [u16],
+    dirty_tiles: [AtomicBool; TILE_COUNT],
+    batch_tile_buf: BatchTileBuf,
+}
 
-impl AtomicFrameBuffer {
+impl<'a> AtomicFrameBuffer<'a> {
-    pub const fn new() -> Self {
+    pub fn new(buffer: &'a mut [u16]) -> Self {
-        Self
+        assert!(buffer.len() == SIZE);
+        Self {
+            fb: buffer,
+            dirty_tiles: core::array::from_fn(|_| AtomicBool::new(true)),
+            batch_tile_buf: [0; MAX_BATCH_TILES * TILE_SIZE * TILE_SIZE],
+        }
     }
 
     fn mark_tiles_dirty(&mut self, rect: Rectangle) {
-        let tiles_x = (SCREEN_WIDTH + TILE_SIZE - 1) / TILE_SIZE;
+        let tiles_x = SCREEN_WIDTH.div_ceil(TILE_SIZE);
         let start_tx = (rect.top_left.x as usize) / TILE_SIZE;
         let end_tx = ((rect.top_left.x + rect.size.width as i32 - 1) as usize) / TILE_SIZE;
         let start_ty = (rect.top_left.y as usize) / TILE_SIZE;
@@ -52,18 +55,12 @@ impl AtomicFrameBuffer {
         for ty in start_ty..=end_ty {
             for tx in start_tx..=end_tx {
                 let tile_idx = ty * tiles_x + tx;
-                unsafe { DIRTY_TILES.get_mut()[tile_idx].store(true, Ordering::Relaxed) };
+                self.dirty_tiles[tile_idx].store(true, Ordering::Release);
             }
         }
     }
 
-    fn set_pixel(&mut self, x: u16, y: u16, color: u16) -> Result<(), ()> {
+    fn set_pixels<P: IntoIterator<Item = u16>>(
-        unsafe { BUFFER[(y as usize * SCREEN_WIDTH) + x as usize] = color };
-
-        Ok(())
-    }
-
-    fn set_pixels_buffered<P: IntoIterator<Item = u16>>(
         &mut self,
         sx: u16,
         sy: u16,
@@ -71,10 +68,10 @@ impl AtomicFrameBuffer {
         ey: u16,
         colors: P,
     ) -> Result<(), ()> {
-        if sx >= self.size().width as u16 - 1
+        if sx >= self.size().width as u16
-            || ex >= self.size().width as u16 - 1
+            || ex >= self.size().width as u16
-            || sy >= self.size().height as u16 - 1
+            || sy >= self.size().height as u16
-            || ey >= self.size().height as u16 - 1
+            || ey >= self.size().height as u16
         {
             return Err(()); // Bounds check
         }
@@ -84,7 +81,7 @@ impl AtomicFrameBuffer {
         for y in sy..=ey {
             for x in sx..=ex {
                 if let Some(color) = color_iter.next() {
-                    unsafe { BUFFER[(y as usize * SCREEN_WIDTH) + x as usize] = color };
+                    self.fb[(y as usize * SCREEN_WIDTH) + x as usize] = color;
                 } else {
                     return Err(()); // Not enough data
                 }
@@ -99,60 +96,17 @@ impl AtomicFrameBuffer {
         Ok(())
     }
 
-    // walk the dirty tiles and mark groups of tiles(meta-tiles) for batched updates
+    // Checks if a full draw would be faster than individual tile batches
-    fn find_meta_tiles(&mut self, tiles_x: usize, tiles_y: usize) -> MetaTileVec {
+    fn should_full_draw(&self) -> bool {
-        let mut meta_tiles: MetaTileVec = Vec::new();
+        let threshold_pixels = SIZE * 80 / 100;
+        let mut dirty_pixels = 0;
 
-        for ty in 0..tiles_y {
+        self.dirty_tiles.iter().any(|tile| {
-            let mut tx = 0;
+            if tile.load(Ordering::Acquire) {
-            while tx < tiles_x {
+                dirty_pixels += TILE_SIZE * TILE_SIZE;
-                let idx = ty * tiles_x + tx;
-                if !unsafe { DIRTY_TILES.get()[idx].load(Ordering::Acquire) } {
-                    tx += 1;
-                    continue;
-                }
-
-                // Start meta-tile at this tile
-                let mut width_tiles = 1;
-                let height_tiles = 1;
-
-                // Grow horizontally, but keep under MAX_TILES_PER_METATILE
-                while tx + width_tiles < tiles_x
-                    && unsafe {
-                        DIRTY_TILES.get()[ty * tiles_x + tx + width_tiles].load(Ordering::Relaxed)
-                    }
-                    && (width_tiles + height_tiles) <= MAX_META_TILES
-                {
-                    width_tiles += 1;
-                }
-
-                // TODO: for simplicity, skipped vertical growth
-
-                for x_off in 0..width_tiles {
-                    unsafe {
-                        DIRTY_TILES.get()[ty * tiles_x + tx + x_off]
-                            .store(false, Ordering::Release);
-                    };
-                }
-
-                // new meta-tile pos
-                let rect = Rectangle::new(
-                    Point::new((tx * TILE_SIZE) as i32, (ty * TILE_SIZE) as i32),
-                    Size::new(
-                        (width_tiles * TILE_SIZE) as u32,
-                        (height_tiles * TILE_SIZE) as u32,
-                    ),
-                );
-
-                if meta_tiles.push(rect).is_err() {
-                    return meta_tiles;
-                };
-
-                tx += width_tiles;
             }
-        }
+            dirty_pixels >= threshold_pixels
-
+        })
-        meta_tiles
     }
 
     /// Sends the entire framebuffer to the display
@@ -171,84 +125,105 @@ impl AtomicFrameBuffer {
                 0,
                 self.size().width as u16 - 1,
                 self.size().height as u16 - 1,
-                unsafe { &BUFFER },
+                &self.fb[..],
             )
             .await?;
 
+        for tile in self.dirty_tiles.iter() {
+            tile.store(false, Ordering::Release);
+        }
+
+        #[cfg(feature = "fps")]
         unsafe {
-            for tile in DIRTY_TILES.get_mut().iter() {
+            crate::display::FPS_COUNTER.measure()
-                tile.store(false, Ordering::Release);
-            }
-        };
-
-        Ok(())
-    }
-
-    /// Sends only dirty tiles (16x16px) individually to the display without batching
-    pub async fn partial_draw<SPI, DC, RST, DELAY: DelayNs>(
-        &mut self,
-        display: &mut ST7365P<SPI, DC, RST, DELAY>,
-    ) -> Result<(), ()>
-    where
-        SPI: SpiDevice,
-        DC: OutputPin,
-        RST: OutputPin,
-    {
-        if unsafe { DIRTY_TILES.get().iter().any(|p| p.load(Ordering::Acquire)) } {
-            let tiles_x = (SCREEN_WIDTH + TILE_SIZE - 1) / TILE_SIZE;
-            let tiles_y = (SCREEN_HEIGHT + TILE_SIZE - 1) / TILE_SIZE;
-
-            let mut tile_buffer = [0u16; TILE_SIZE * TILE_SIZE];
-
-            for ty in 0..tiles_y {
-                for tx in 0..tiles_x {
-                    if unsafe { !DIRTY_TILES.get()[ty * tiles_x + tx].load(Ordering::Acquire) } {
-                        continue;
-                    }
-
-                    let x = tx * TILE_SIZE;
-                    let y = ty * TILE_SIZE;
-
-                    // Copy pixels for the tile into tile_buffer
-                    for row in 0..TILE_SIZE {
-                        for col in 0..TILE_SIZE {
-                            let actual_x = x + col;
-                            let actual_y = y + row;
-
-                            if actual_x < SCREEN_WIDTH && actual_y < SCREEN_HEIGHT {
-                                let idx = actual_y * SCREEN_WIDTH + actual_x;
-                                tile_buffer[row * TILE_SIZE + col] = unsafe { BUFFER[idx] };
-                            } else {
-                                // Out of bounds, fill with zero (or background)
-                                tile_buffer[row * TILE_SIZE + col] = 0;
-                            }
-                        }
-                    }
-
-                    // Send the tile's pixel data to the display
-                    display
-                        .set_pixels_buffered(
-                            x as u16,
-                            y as u16,
-                            (x + TILE_SIZE - 1).min(SCREEN_WIDTH - 1) as u16,
-                            (y + TILE_SIZE - 1).min(SCREEN_HEIGHT - 1) as u16,
-                            &tile_buffer,
-                        )
-                        .await?;
-
-                    // Mark tile as clean
-                    unsafe {
-                        DIRTY_TILES.get_mut()[ty * tiles_x + tx].store(false, Ordering::Release)
-                    };
-                }
-            }
         }
 
         Ok(())
     }
 
-    /// Sends only dirty tiles (16x16px) in batches to the display
+    // used when doing a full screen refresh fps must be drawn into fb
-    pub async fn partial_draw_batched<SPI, DC, RST, DELAY>(
+    // unfortunately it is not garenteed to not be drawn over before
+    // being pushed to the display
+    #[cfg(feature = "fps")]
+    pub fn draw_fps_into_fb(&mut self) {
+        unsafe {
+            let canvas = &FPS_CANVAS.canvas;
+
+            for y in 0..FPS_CANVAS_HEIGHT {
+                let fb_y = FPS_CANVAS_Y + y;
+                let fb_row_start = fb_y * SCREEN_WIDTH + FPS_CANVAS_X;
+                let canvas_row_start = y * FPS_CANVAS_WIDTH;
+
+                self.fb[fb_row_start..fb_row_start + FPS_CANVAS_WIDTH].copy_from_slice(
+                    &canvas[canvas_row_start..canvas_row_start + FPS_CANVAS_WIDTH],
+                );
+            }
+        }
+    }
+
+    // copy N tiles horizontally to the right into batch tile buf
+    fn append_tiles_to_batch(
+        &mut self,
+        tile_x: u16,
+        tile_y: u16,
+        total_tiles: u16, // number of tiles being written to buf
+    ) {
+        debug_assert!(total_tiles as usize <= NUM_TILE_COLS);
+        for batch_row_num in 0..TILE_SIZE {
+            let batch_row_offset = batch_row_num * total_tiles as usize * TILE_SIZE;
+            let batch_row = &mut self.batch_tile_buf
+                [batch_row_offset..batch_row_offset + (total_tiles as usize * TILE_SIZE)];
+
+            let fb_row_offset = (tile_y as usize * TILE_SIZE + batch_row_num) * SCREEN_WIDTH
+                + tile_x as usize * TILE_SIZE;
+            let fb_row =
+                &self.fb[fb_row_offset..fb_row_offset + (total_tiles as usize * TILE_SIZE)];
+
+            batch_row.copy_from_slice(fb_row);
+
+            // override fps pixel region with fps
+            // avoids writing to fps, and having it overridden before draw
+            #[cfg(feature = "fps")]
+            {
+                let global_y = tile_y as usize * TILE_SIZE + batch_row_num;
+
+                if global_y >= FPS_CANVAS_Y && global_y < FPS_CANVAS_Y + FPS_CANVAS_HEIGHT {
+                    let start_x = tile_x as usize * TILE_SIZE;
+                    let end_x = start_x + (total_tiles as usize * TILE_SIZE);
+
+                    // horizontal overlap check
+                    let fps_x0 = FPS_CANVAS_X;
+                    let fps_x1 = FPS_CANVAS_X + FPS_CANVAS_WIDTH;
+
+                    let x0 = start_x.max(fps_x0);
+                    let x1 = end_x.min(fps_x1);
+
+                    if x1 > x0 {
+                        let row_in_fps = global_y - FPS_CANVAS_Y;
+                        let fps_off = row_in_fps
+                            .checked_mul(FPS_CANVAS_WIDTH)
+                            .and_then(|v| v.checked_add(x0 - fps_x0));
+                        let batch_off = x0 - start_x;
+                        let len = x1 - x0;
+
+                        if let Some(fps_off) = fps_off {
+                            let fps_len_ok = fps_off + len <= unsafe { FPS_CANVAS.canvas.len() };
+                            let batch_len_ok = batch_off + len <= batch_row.len();
+
+                            if fps_len_ok && batch_len_ok {
+                                batch_row[batch_off..batch_off + len].copy_from_slice(unsafe {
+                                    &FPS_CANVAS.canvas[fps_off..fps_off + len]
+                                });
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    // Pushes tiles to the display in batches to avoid full frame pushes (unless needed)
+    pub async fn partial_draw<SPI, DC, RST, DELAY>(
         &mut self,
         display: &mut ST7365P<SPI, DC, RST, DELAY>,
     ) -> Result<(), ()>
@@ -258,65 +233,85 @@ impl AtomicFrameBuffer {
         RST: OutputPin,
         DELAY: DelayNs,
     {
-        if unsafe { DIRTY_TILES.get().iter().any(|p| p.load(Ordering::Acquire)) } {
+        if self.should_full_draw() {
-            let tiles_x = (SCREEN_WIDTH + TILE_SIZE - 1) / TILE_SIZE;
+            #[cfg(feature = "fps")]
-            let tiles_y = (SCREEN_HEIGHT + TILE_SIZE - 1) / TILE_SIZE;
+            self.draw_fps_into_fb();
+            return self.draw(display).await;
+        }
 
-            let meta_tiles = self.find_meta_tiles(tiles_x, tiles_y);
+        #[cfg(feature = "fps")]
+        {
+            let fps_tile_x = FPS_CANVAS_X / TILE_SIZE;
+            let fps_tile_y = FPS_CANVAS_Y / TILE_SIZE;
+            let fps_tile_w = (FPS_CANVAS_WIDTH + TILE_SIZE - 1) / TILE_SIZE;
+            let fps_tile_h = (FPS_CANVAS_HEIGHT + TILE_SIZE - 1) / TILE_SIZE;
 
-            // buffer for copying meta tiles before sending to display
+            for ty in fps_tile_y..fps_tile_y + fps_tile_h {
-            let mut pixel_buffer: heapless::Vec<u16, { MAX_META_TILES * TILE_SIZE * TILE_SIZE }> =
+                for tx in fps_tile_x..fps_tile_x + fps_tile_w {
-                Vec::new();
+                    self.dirty_tiles[ty * NUM_TILE_COLS + tx].store(true, Ordering::Release);
-
-            for rect in meta_tiles {
-                let rect_width = rect.size.width as usize;
-                let rect_height = rect.size.height as usize;
-                let rect_x = rect.top_left.x as usize;
-                let rect_y = rect.top_left.y as usize;
-
-                pixel_buffer.clear();
-
-                for row in 0..rect_height {
-                    let y = rect_y + row;
-                    let start = y * SCREEN_WIDTH + rect_x;
-                    let end = start + rect_width;
-
-                    // Safe: we guarantee buffer will not exceed MAX_META_TILE_PIXELS
-                    pixel_buffer
-                        .extend_from_slice(unsafe { &BUFFER[start..end] })
-                        .unwrap();
-                }
-
-                display
-                    .set_pixels_buffered(
-                        rect_x as u16,
-                        rect_y as u16,
-                        (rect_x + rect_width - 1) as u16,
-                        (rect_y + rect_height - 1) as u16,
-                        &pixel_buffer,
-                    )
-                    .await?;
-
-                // walk the meta-tile and set as clean
-                let start_tx = rect_x / TILE_SIZE;
-                let start_ty = rect_y / TILE_SIZE;
-                let end_tx = (rect_x + rect_width - 1) / TILE_SIZE;
-                let end_ty = (rect_y + rect_height - 1) / TILE_SIZE;
-
-                for ty in start_ty..=end_ty {
-                    for tx in start_tx..=end_tx {
-                        let tile_idx = ty * tiles_x + tx;
-                        unsafe { DIRTY_TILES.get_mut()[tile_idx].store(false, Ordering::Release) };
-                    }
                 }
             }
         }
 
+        for tile_row in 0..NUM_TILE_ROWS {
+            let row_start_idx = tile_row * NUM_TILE_COLS;
+            let mut col = 0;
+
+            while col < NUM_TILE_COLS {
+                // Check for dirty tile
+                if self.dirty_tiles[row_start_idx + col].swap(false, Ordering::Acquire) {
+                    let run_start = col;
+                    let mut scan_col = col;
+                    let mut run_len = 1;
+
+                    // Extend run while contiguous dirty tiles and within MAX_BATCH_TILES
+                    while scan_col + 1 < NUM_TILE_COLS
+                        && self.dirty_tiles[row_start_idx + col + 1].load(Ordering::Acquire)
+                        && run_len < MAX_BATCH_TILES
+                    {
+                        scan_col += 1;
+                        run_len += 1;
+                    }
+
+                    // Copy the whole horizontal run into the batch buffer in one call
+                    let tile_x = run_start;
+                    let tile_y = tile_row;
+                    self.append_tiles_to_batch(tile_x as u16, tile_y as u16, run_len as u16);
+
+                    // Compute coordinates for display write
+                    let start_x = tile_x * TILE_SIZE;
+                    let end_x = start_x + run_len * TILE_SIZE - 1;
+                    let start_y = tile_y * TILE_SIZE;
+                    let end_y = start_y + TILE_SIZE - 1;
+
+                    // Send batch to display
+                    display
+                        .set_pixels_buffered(
+                            start_x as u16,
+                            start_y as u16,
+                            end_x as u16,
+                            end_y as u16,
+                            &self.batch_tile_buf[..run_len * TILE_SIZE * TILE_SIZE],
+                        )
+                        .await?;
+
+                    col = scan_col;
+                }
+
+                col += 1;
+            }
+        }
+
+        #[cfg(feature = "fps")]
+        unsafe {
+            crate::display::FPS_COUNTER.measure()
+        }
+
         Ok(())
     }
 }
 
-impl DrawTarget for AtomicFrameBuffer {
+impl<'a> DrawTarget for AtomicFrameBuffer<'a> {
     type Error = ();
     type Color = Rgb565;
 
@@ -325,17 +320,20 @@ impl DrawTarget for AtomicFrameBuffer {
         I: IntoIterator<Item = Pixel<Self::Color>>,
     {
         let mut dirty_rect: Option<Rectangle> = None;
+        let mut changed = false;
 
         for Pixel(coord, color) in pixels {
             if coord.x >= 0 && coord.y >= 0 {
-                let x = coord.x as i32;
+                let x = coord.x;
-                let y = coord.y as i32;
+                let y = coord.y;
 
                 if (x as usize) < SCREEN_WIDTH && (y as usize) < SCREEN_HEIGHT {
-                    unsafe {
+                    let idx = (y as usize) * SCREEN_WIDTH + (x as usize);
-                        BUFFER[(y as usize) * SCREEN_WIDTH + (x as usize)] =
+                    let raw_color = RawU16::from(color).into_inner();
-                            RawU16::from(color).into_inner()
+                    if self.fb[idx] != raw_color {
-                    };
+                        self.fb[idx] = raw_color;
+                        changed = true;
+                    }
 
                     if let Some(ref mut rect) = dirty_rect {
                         rect.top_left.x = rect.top_left.x.min(x);
@@ -351,7 +349,7 @@ impl DrawTarget for AtomicFrameBuffer {
             }
         }
 
-        if let Some(rect) = dirty_rect {
+        if changed && let Some(rect) = dirty_rect {
             self.mark_tiles_dirty(rect);
         }
 
@@ -370,6 +368,7 @@ impl DrawTarget for AtomicFrameBuffer {
             let area_width = area.size.width;
             let area_height = area.size.height;
             let mut colors = colors.into_iter();
+            let mut changed = false;
 
             for y in 0..area_height {
                 for x in 0..area_width {
@@ -377,11 +376,12 @@ impl DrawTarget for AtomicFrameBuffer {
 
                     if drawable_area.contains(p) {
                         if let Some(color) = colors.next() {
-                            self.set_pixel(
+                            let idx = (p.y as usize * SCREEN_WIDTH) + (p.x as usize);
-                                p.x as u16,
+                            let raw_color = RawU16::from(color).into_inner();
-                                p.y as u16,
+                            if self.fb[idx] != raw_color {
-                                RawU16::from(color).into_inner(),
+                                self.fb[idx] = raw_color;
-                            )?;
+                                changed = true;
+                            }
                         } else {
                             break;
                         }
@@ -392,7 +392,9 @@ impl DrawTarget for AtomicFrameBuffer {
                 }
             }
 
-            self.mark_tiles_dirty(*area);
+            if changed {
+                self.mark_tiles_dirty(*area);
+            }
         }
 
         Ok(())
@@ -401,32 +403,175 @@ impl DrawTarget for AtomicFrameBuffer {
     fn fill_solid(&mut self, area: &Rectangle, color: Self::Color) -> Result<(), Self::Error> {
         self.fill_contiguous(
             area,
-            core::iter::repeat(color).take((self.size().width * self.size().height) as usize),
+            core::iter::repeat_n(color, (self.size().width * self.size().height) as usize),
         )
     }
 
     fn clear(&mut self, color: Self::Color) -> Result<(), Self::Error> {
-        self.set_pixels_buffered(
+        self.set_pixels(
             0,
             0,
             self.size().width as u16 - 1,
             self.size().height as u16 - 1,
-            core::iter::repeat(RawU16::from(color).into_inner())
+            core::iter::repeat_n(
-                .take((self.size().width * self.size().height) as usize),
+                RawU16::from(color).into_inner(),
+                (self.size().width * self.size().height) as usize,
+            ),
         )?;
 
-        unsafe {
+        for tile in self.dirty_tiles.iter() {
-            for tile in DIRTY_TILES.get_mut().iter() {
+            tile.store(true, Ordering::Release);
-                tile.store(true, Ordering::Relaxed);
-            }
         }
 
         Ok(())
     }
 }
 
-impl OriginDimensions for AtomicFrameBuffer {
+impl<'a> OriginDimensions for AtomicFrameBuffer<'a> {
     fn size(&self) -> Size {
         Size::new(SCREEN_WIDTH as u32, SCREEN_HEIGHT as u32)
     }
 }
+
+#[cfg(feature = "fps")]
+pub mod fps {
+    use crate::display::SCREEN_WIDTH;
+    use core::fmt::Write;
+    use embassy_time::{Duration, Instant};
+    use embedded_graphics::{
+        Drawable, Pixel,
+        draw_target::DrawTarget,
+        geometry::Point,
+        mono_font::{MonoTextStyle, ascii::FONT_8X13},
+        pixelcolor::Rgb565,
+        prelude::{IntoStorage, OriginDimensions, RgbColor, Size},
+        text::{Alignment, Text},
+    };
+
+    pub static mut FPS_COUNTER: FpsCounter = FpsCounter::new();
+    pub static mut FPS_CANVAS: FpsCanvas = FpsCanvas::new();
+
+    // "FPS: 120" = 8 len
+    const FPS_LEN: usize = 8;
+    pub const FPS_CANVAS_WIDTH: usize = (FONT_8X13.character_size.width + 4) as usize * FPS_LEN;
+    pub const FPS_CANVAS_HEIGHT: usize = FONT_8X13.character_size.height as usize;
+
+    // puts canvas in the top right of the display
+    // top left point of canvas
+    pub const FPS_CANVAS_X: usize = SCREEN_WIDTH - FPS_CANVAS_WIDTH;
+    pub const FPS_CANVAS_Y: usize = 0;
+
+    pub struct FpsCanvas {
+        pub canvas: [u16; FPS_CANVAS_HEIGHT * FPS_CANVAS_WIDTH],
+    }
+
+    impl FpsCanvas {
+        const fn new() -> Self {
+            Self {
+                canvas: [0; FPS_CANVAS_HEIGHT * FPS_CANVAS_WIDTH],
+            }
+        }
+
+        fn clear(&mut self) {
+            for p in &mut self.canvas {
+                *p = 0;
+            }
+        }
+
+        pub async fn draw_fps(&mut self) {
+            let mut buf: heapless::String<FPS_LEN> = heapless::String::new();
+            let fps = unsafe { FPS_COUNTER.smoothed };
+            let _ = write!(buf, "FPS: {}", fps as u8);
+
+            self.clear();
+            let text_style = MonoTextStyle::new(&FONT_8X13, Rgb565::WHITE);
+            Text::with_alignment(
+                buf.as_str(),
+                Point::new(
+                    FPS_CANVAS_WIDTH as i32 / 2,
+                    (FPS_CANVAS_HEIGHT as i32 + 8) / 2,
+                ),
+                text_style,
+                Alignment::Center,
+            )
+            .draw(self)
+            .unwrap();
+        }
+    }
+
+    impl DrawTarget for FpsCanvas {
+        type Error = ();
+        type Color = Rgb565;
+
+        fn draw_iter<I>(&mut self, pixels: I) -> Result<(), Self::Error>
+        where
+            I: IntoIterator<Item = Pixel<Self::Color>>,
+        {
+            for Pixel(point, color) in pixels {
+                if point.x < 0
+                    || point.x >= FPS_CANVAS_WIDTH as i32
+                    || point.y < 0
+                    || point.y >= FPS_CANVAS_HEIGHT as i32
+                {
+                    continue;
+                }
+
+                let index = (point.y as usize) * FPS_CANVAS_WIDTH + point.x as usize;
+                self.canvas[index] = color.into_storage();
+            }
+            Ok(())
+        }
+    }
+
+    impl OriginDimensions for FpsCanvas {
+        fn size(&self) -> Size {
+            Size::new(FPS_CANVAS_WIDTH as u32, FPS_CANVAS_HEIGHT as u32)
+        }
+    }
+
+    pub struct FpsCounter {
+        last_frame: Option<Instant>,
+        smoothed: f32,
+        last_draw: Option<Instant>,
+    }
+
+    impl FpsCounter {
+        pub const fn new() -> Self {
+            Self {
+                last_frame: None,
+                smoothed: 0.0,
+                last_draw: None,
+            }
+        }
+
+        // Is called once per frame or partial frame to update FPS
+        pub fn measure(&mut self) {
+            let now = Instant::now();
+
+            if let Some(last) = self.last_frame {
+                let dt_us = (now - last).as_micros() as f32;
+                if dt_us > 0.0 {
+                    let current = 1_000_000.0 / dt_us;
+                    self.smoothed = if self.smoothed == 0.0 {
+                        current
+                    } else {
+                        0.9 * self.smoothed + 0.1 * current
+                    };
+                }
+            }
+
+            self.last_frame = Some(now);
+        }
+
+        pub fn should_draw(&mut self) -> bool {
+            let now = Instant::now();
+            match self.last_draw {
+                Some(last) if now - last < Duration::from_millis(200) => false,
+                _ => {
+                    self.last_draw = Some(now);
+                    true
+                }
+            }
+        }
+    }
+}

kernel/src/heap.rs

@@ -0,0 +1,95 @@
+// This whole file was taken from:
+// https://github.com/wezterm/picocalc-wezterm/blob/main/src/heap.rs
+
+use core::alloc::{GlobalAlloc, Layout};
+use core::sync::atomic::{AtomicUsize, Ordering};
+use embedded_alloc::LlffHeap as Heap;
+
+pub static mut HEAP: PsramHeap = PsramHeap::empty();
+
+struct Region {
+    start: AtomicUsize,
+    size: AtomicUsize,
+}
+
+impl Region {
+    const fn default() -> Self {
+        Self {
+            start: AtomicUsize::new(0),
+            size: AtomicUsize::new(0),
+        }
+    }
+
+    fn contains(&self, address: usize) -> bool {
+        let start = self.start.load(Ordering::Relaxed);
+        let end = start + self.size.load(Ordering::Relaxed);
+        (start..end).contains(&address)
+    }
+
+    fn new(start: usize, size: usize) -> Self {
+        Self {
+            start: AtomicUsize::new(start),
+            size: AtomicUsize::new(size),
+        }
+    }
+}
+
+/// FIXME: PSRAM-allocated memory isn't compatible with
+/// CAS atomics, so we might need a bit of a think about this!
+pub struct PsramHeap {
+    heap: Heap,
+    region: Region,
+}
+
+impl PsramHeap {
+    pub const fn empty() -> Self {
+        Self {
+            heap: Heap::empty(),
+            region: Region::default(),
+        }
+    }
+
+    unsafe fn add_psram(&self, region: Region) {
+        let start = region.start.load(Ordering::SeqCst);
+        let size = region.size.load(Ordering::SeqCst);
+        unsafe {
+            self.heap.init(start, size);
+        }
+        self.region.start.store(start, Ordering::SeqCst);
+        self.region.size.store(size, Ordering::SeqCst);
+    }
+
+    pub fn used(&self) -> usize {
+        self.heap.used()
+    }
+
+    pub fn free(&self) -> usize {
+        self.heap.free()
+    }
+}
+
+unsafe impl GlobalAlloc for PsramHeap {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        unsafe {
+            let ptr = self.heap.alloc(layout);
+            if !ptr.is_null() {
+                return ptr;
+            } else {
+                panic!("HEAP FULL");
+            }
+        }
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        unsafe {
+            let ptr_usize = ptr as usize;
+            if self.region.contains(ptr_usize) {
+                self.heap.dealloc(ptr, layout);
+            }
+        }
+    }
+}
+
+pub fn init_qmi_psram_heap(size: u32) {
+    unsafe { HEAP.add_psram(Region::new(0x11000000, size as usize)) }
+}

kernel/src/main.rs

@@ -1,100 +1,145 @@
 #![feature(impl_trait_in_assoc_type)]
-#![feature(type_alias_impl_trait)]
+#![feature(str_from_raw_parts)]
-#![feature(ascii_char)]
 #![cfg_attr(not(test), no_std)]
 #![cfg_attr(not(test), no_main)]
 #![allow(static_mut_refs)]
+#![feature(allocator_api)]
+#![feature(slice_ptr_get)]
 
 extern crate alloc;
 
-mod abi;
+mod audio;
 mod display;
 mod elf;
 mod framebuffer;
+// TODO: NEED TO UPDATE MCU TO TEST BATTERY READS
+#[allow(unused)]
 mod peripherals;
+#[allow(unused)]
 mod scsi;
 mod storage;
+mod syscalls;
 mod ui;
+#[allow(unused)]
 mod usb;
 mod utils;
 
+#[cfg(feature = "psram")]
+#[allow(unused)]
+mod heap;
+#[cfg(feature = "psram")]
+#[allow(unused)]
+mod psram;
+
+#[cfg(feature = "psram")]
+use crate::{heap::init_qmi_psram_heap, psram::init_psram_qmi};
+
 use crate::{
-    display::{FRAMEBUFFER, clear_fb, display_handler, init_display},
+    audio::{AUDIO_BUFFER_WRITTEN, audio_handler, clear_audio_buffers},
-    elf::load_binary,
+    display::{FRAMEBUFFER, display_handler, init_display},
-    peripherals::{
+    peripherals::{conf_peripherals, keyboard::read_keyboard_fifo},
-        conf_peripherals,
+    scsi::MSC_SHUTDOWN,
-        keyboard::{KeyCode, KeyState, read_keyboard_fifo},
-    },
     storage::{SDCARD, SdCard},
-    ui::{SELECTIONS, ui_handler},
+    syscalls::{KEY_CACHE, MS_SINCE_LAUNCH},
-    usb::usb_handler,
+    ui::{SELECTIONS, clear_selection, ui_handler},
 };
-use abi_sys::EntryFn;
+use bumpalo::Bump;
-
+use core::sync::atomic::{AtomicBool, Ordering};
-use {defmt_rtt as _, panic_probe as _};
-
-use assign_resources::assign_resources;
-use defmt::unwrap;
 use embassy_executor::{Executor, Spawner};
-use embassy_futures::join::{join, join3, join4, join5};
+use embassy_futures::{join::join, select::select};
 use embassy_rp::{
     Peri,
+    clocks::ClockConfig,
+    config::Config,
     gpio::{Input, Level, Output, Pull},
     i2c::{self, I2c},
     multicore::{Stack, spawn_core1},
     peripherals::{
-        DMA_CH0, DMA_CH1, I2C1, PIN_6, PIN_7, PIN_10, PIN_11, PIN_12, PIN_13, PIN_14, PIN_15,
+        DMA_CH0, DMA_CH1, DMA_CH3, DMA_CH4, I2C1, PIN_2, PIN_3, PIN_6, PIN_7, PIN_10, PIN_11,
-        PIN_16, PIN_17, PIN_18, PIN_19, PIN_22, SPI0, SPI1, USB,
+        PIN_12, PIN_13, PIN_14, PIN_15, PIN_16, PIN_17, PIN_18, PIN_19, PIN_20, PIN_21, PIN_22,
+        PIN_26, PIN_27, PIO0, SPI0, SPI1, USB, WATCHDOG,
     },
+    pio::{self, Common, Pio, StateMachine},
     spi::{self, Spi},
     usb as embassy_rp_usb,
+    watchdog::{ResetReason, Watchdog},
 };
 use embassy_sync::{
-    blocking_mutex::raw::CriticalSectionRawMutex, channel::Channel, mutex::Mutex, signal::Signal,
+    blocking_mutex::raw::CriticalSectionRawMutex, channel::Channel, signal::Signal,
+};
+use embassy_time::{Delay, Duration, Instant, Ticker, Timer};
+use embedded_graphics::{
+    pixelcolor::Rgb565,
+    prelude::{DrawTarget, RgbColor},
 };
-use embassy_time::{Delay, Timer};
 use embedded_hal_bus::spi::ExclusiveDevice;
 use embedded_sdmmc::SdCard as SdmmcSdCard;
-use heapless::spsc::Queue;
-use shared::keyboard::KeyEvent;
 use static_cell::StaticCell;
 use talc::*;
+use userlib_sys::EntryFn;
+use {defmt_rtt as _, panic_probe as _};
 
 embassy_rp::bind_interrupts!(struct Irqs {
     I2C1_IRQ => i2c::InterruptHandler<I2C1>;
     USBCTRL_IRQ => embassy_rp_usb::InterruptHandler<USB>;
+    PIO0_IRQ_0 => pio::InterruptHandler<PIO0>;
 });
 
 static mut CORE1_STACK: Stack<16384> = Stack::new();
 static EXECUTOR0: StaticCell<Executor> = StaticCell::new();
 static EXECUTOR1: StaticCell<Executor> = StaticCell::new();
 
-static mut ARENA: [u8; 10 * 1024] = [0; 10 * 1024];
+#[cfg(not(feature = "pimoroni2w"))]
+static mut ARENA: [u8; 250 * 1024] = [0; 250 * 1024];
+#[cfg(feature = "pimoroni2w")]
+static mut ARENA: [u8; 400 * 1024] = [0; 400 * 1024];
 
 #[global_allocator]
 static ALLOCATOR: Talck<spin::Mutex<()>, ClaimOnOom> =
     Talc::new(unsafe { ClaimOnOom::new(Span::from_array(core::ptr::addr_of!(ARENA).cast_mut())) })
         .lock();
 
-static TASK_STATE: Mutex<CriticalSectionRawMutex, TaskState> = Mutex::new(TaskState::Ui);
+#[embassy_executor::task]
-static TASK_STATE_CHANGED: Signal<CriticalSectionRawMutex, ()> = Signal::new();
+async fn watchdog_task(mut watchdog: Watchdog) {
+    if let Some(reason) = watchdog.reset_reason() {
+        let _reason = match reason {
+            ResetReason::Forced => "forced",
+            ResetReason::TimedOut => "timed out",
+        };
+        #[cfg(feature = "defmt")]
+        defmt::error!("Watchdog reset reason: {}", _reason);
+    }
 
-#[derive(Copy, Clone, PartialEq)]
+    watchdog.start(Duration::from_secs(3));
-enum TaskState {
+
-    Ui,
+    let mut ticker = Ticker::every(Duration::from_secs(2));
-    Kernel,
+    loop {
+        watchdog.feed();
+        ticker.next().await;
+    }
 }
 
+static ENABLE_UI: AtomicBool = AtomicBool::new(true);
+static UI_CHANGE: Signal<CriticalSectionRawMutex, ()> = Signal::new();
+
+const OVERCLOCK: u32 = 300_000_000;
+
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) {
-    let p = embassy_rp::init(Default::default());
+    let p = if cfg!(feature = "overclock") {
+        let clocks = ClockConfig::system_freq(OVERCLOCK).unwrap();
+        let config = Config::new(clocks);
+        embassy_rp::init(config)
+    } else {
+        embassy_rp::init(Default::default())
+    };
 
     spawn_core1(
         p.CORE1,
         unsafe { &mut *core::ptr::addr_of_mut!(CORE1_STACK) },
         move || {
             let executor1 = EXECUTOR1.init(Executor::new());
-            executor1.run(|spawner| unwrap!(spawner.spawn(userland_task())));
+            executor1.run(|spawner| spawner.spawn(userland_task()).unwrap());
         },
     );
 
@@ -109,6 +154,19 @@ async fn main(_spawner: Spawner) {
         data: p.PIN_14,
         reset: p.PIN_15,
     };
+    let Pio {
+        common, sm0, sm1, ..
+    } = Pio::new(p.PIO0, Irqs);
+
+    let audio = Audio {
+        pio: common,
+        sm0,
+        dma0: p.DMA_CH3,
+        left: p.PIN_26,
+        sm1,
+        dma1: p.DMA_CH4,
+        right: p.PIN_27,
+    };
     let sd = Sd {
         spi: p.SPI0,
         clk: p.PIN_18,
@@ -117,41 +175,66 @@ async fn main(_spawner: Spawner) {
         cs: p.PIN_17,
         det: p.PIN_22,
     };
+    // let psram = Psram {
+    //     pio: p.PIO0,
+    //     sclk: p.PIN_21,
+    //     mosi: p.PIN_2,
+    //     miso: p.PIN_3,
+    //     cs: p.PIN_20,
+    //     dma1: p.DMA_CH3,
+    //     dma2: p.DMA_CH4,
+    // };
     let mcu = Mcu {
         i2c: p.I2C1,
         clk: p.PIN_7,
         data: p.PIN_6,
     };
     let executor0 = EXECUTOR0.init(Executor::new());
-    executor0.run(|spawner| unwrap!(spawner.spawn(kernel_task(display, sd, mcu, p.USB))));
+    executor0.run(|spawner| {
+        spawner
+            .spawn(kernel_task(
+                spawner, p.WATCHDOG, display, audio, sd, mcu, p.USB,
+            ))
+            .unwrap()
+    });
 }
 
 // One-slot channel to pass EntryFn from core1
-static BINARY_CH: Channel<CriticalSectionRawMutex, EntryFn, 1> = Channel::new();
+static BINARY_CH: Channel<CriticalSectionRawMutex, (EntryFn, Bump), 1> = Channel::new();
 
 // runs dynamically loaded elf files
 #[embassy_executor::task]
 async fn userland_task() {
     let recv = BINARY_CH.receiver();
     loop {
-        let entry = recv.receive().await;
+        let (entry, _bump) = recv.receive().await;
-        defmt::info!("Got Entry");
 
         // disable kernel ui
         {
-            let mut state = TASK_STATE.lock().await;
+            ENABLE_UI.store(false, Ordering::Release);
-            *state = TaskState::Kernel;
+            UI_CHANGE.signal(());
+
+            clear_selection().await;
+
+            MSC_SHUTDOWN.signal(());
         }
 
-        // clear_fb();
+        unsafe { MS_SINCE_LAUNCH = Some(Instant::now()) };
-
+        #[cfg(feature = "defmt")]
         defmt::info!("Executing Binary");
-        entry().await;
+        entry();
 
         // enable kernel ui
         {
-            let mut state = TASK_STATE.lock().await;
+            AUDIO_BUFFER_WRITTEN.store(false, Ordering::Release);
-            *state = TaskState::Ui;
+            clear_audio_buffers();
+
+            ENABLE_UI.store(true, Ordering::Release);
+            UI_CHANGE.signal(());
+            unsafe { FRAMEBUFFER.as_mut().unwrap().clear(Rgb565::BLACK).unwrap() };
+
+            let mut selections = SELECTIONS.lock().await;
+            selections.set_changed(true);
         }
     }
 }
@@ -167,6 +250,15 @@ struct Display {
     data: Peri<'static, PIN_14>,
     reset: Peri<'static, PIN_15>,
 }
+struct Audio {
+    pio: Common<'static, PIO0>,
+    dma0: Peri<'static, DMA_CH3>,
+    sm0: StateMachine<'static, PIO0, 0>,
+    left: Peri<'static, PIN_26>,
+    dma1: Peri<'static, DMA_CH4>,
+    sm1: StateMachine<'static, PIO0, 1>,
+    right: Peri<'static, PIN_27>,
+}
 struct Sd {
     spi: Peri<'static, SPI0>,
     clk: Peri<'static, PIN_18>,
@@ -175,24 +267,33 @@ struct Sd {
     cs: Peri<'static, PIN_17>,
     det: Peri<'static, PIN_22>,
 }
+#[allow(dead_code)]
+struct Psram {
+    pio: Peri<'static, PIO0>,
+    sclk: Peri<'static, PIN_21>,
+    mosi: Peri<'static, PIN_2>,
+    miso: Peri<'static, PIN_3>,
+    cs: Peri<'static, PIN_20>,
+    dma1: Peri<'static, DMA_CH3>,
+    dma2: Peri<'static, DMA_CH4>,
+}
 struct Mcu {
     i2c: Peri<'static, I2C1>,
     clk: Peri<'static, PIN_7>,
     data: Peri<'static, PIN_6>,
 }
 
-#[embassy_executor::task]
+async fn setup_mcu(mcu: Mcu) {
-async fn kernel_task(display: Display, sd: Sd, mcu: Mcu, usb: Peri<'static, USB>) {
+    // MCU i2c bus for peripherals( keyboard)
-    // MCU i2c bus for peripherals
     let mut config = i2c::Config::default();
     config.frequency = 400_000;
     let i2c1 = I2c::new_async(mcu.i2c, mcu.clk, mcu.data, Irqs, config);
     conf_peripherals(i2c1).await;
+}
 
-    Timer::after_millis(250).await;
+async fn setup_display(display: Display, spawner: Spawner) {
-
     let mut config = spi::Config::default();
-    config.frequency = 16_000_000;
+    config.frequency = 192_000_000;
     let spi = Spi::new(
         display.spi,
         display.clk,
@@ -203,66 +304,130 @@ async fn kernel_task(display: Display, sd: Sd, mcu: Mcu, usb: Peri<'static, USB>
         config,
     );
     let display = init_display(spi, display.cs, display.data, display.reset).await;
-
+    spawner.spawn(display_handler(display)).unwrap();
-    let display_fut = display_handler(display);
-
-    let ui_fut = ui_handler();
-
-    let binary_search_fut = async {
-        loop {
-            {
-                let mut guard = SDCARD.get().lock().await;
-
-                if let Some(sd) = guard.as_mut() {
-                    let files = sd.list_files_by_extension(".bin").unwrap();
-                    let mut select = SELECTIONS.lock().await;
-
-                    if select.selections != files {
-                        select.selections = files;
-                        select.reset();
-                    }
-                }
-            }
-            Timer::after_secs(5).await;
-        }
-    };
-
-    {
-        let mut config = spi::Config::default();
-        config.frequency = 400_000;
-        let spi = Spi::new_blocking(sd.spi, sd.clk, sd.mosi, sd.miso, config.clone());
-        let cs = Output::new(sd.cs, Level::High);
-        let det = Input::new(sd.det, Pull::None);
-
-        let device = ExclusiveDevice::new(spi, cs, Delay).unwrap();
-        let sdcard = SdmmcSdCard::new(device, Delay);
-
-        config.frequency = 32_000_000;
-        sdcard.spi(|dev| dev.bus_mut().set_config(&config));
-        SDCARD.get().lock().await.replace(SdCard::new(sdcard, det));
-    };
-
-    let usb = embassy_rp_usb::Driver::new(usb, Irqs);
-    let usb_fut = usb_handler(usb);
-
-    let key_abi_fut = async {
-        loop {
-            Timer::after_millis(100).await;
-            get_keys().await
-        }
-    };
-
-    join5(display_fut, ui_fut, usb_fut, binary_search_fut, key_abi_fut).await;
 }
 
-static mut KEY_CACHE: Queue<KeyEvent, 32> = Queue::new();
+// psram is kind of useless on the pico calc
+// ive opted to use the pimoroni with on onboard xip psram instead
+// async fn setup_psram(psram: Psram) {
+//     let psram = init_psram(
+//         psram.pio, psram.sclk, psram.mosi, psram.miso, psram.cs, psram.dma1, psram.dma2,
+//     )
+//     .await;
 
-async fn get_keys() {
+//     #[cfg(feature = "defmt")]
-    if let Some(event) = read_keyboard_fifo().await {
+//     defmt::info!("psram size: {}", psram.size);
-        if let KeyState::Pressed = event.state {
+
+//     if psram.size == 0 {
+//         #[cfg(feature = "defmt")]
+//         defmt::info!("\u{1b}[1mExternal PSRAM was NOT found!\u{1b}[0m");
+//     }
+// }
+
+#[cfg(feature = "psram")]
+async fn setup_qmi_psram() {
+    Timer::after_millis(250).await;
+    let psram_qmi_size = init_psram_qmi(&embassy_rp::pac::QMI, &embassy_rp::pac::XIP_CTRL);
+    #[cfg(feature = "defmt")]
+    defmt::info!("size:  {}", psram_qmi_size);
+    Timer::after_millis(100).await;
+
+    if psram_qmi_size > 0 {
+        init_qmi_psram_heap(psram_qmi_size);
+        return;
+    } else {
+        panic!("qmi psram not initialized");
+    }
+}
+
+async fn setup_sd(sd: Sd) {
+    let mut config = spi::Config::default();
+    config.frequency = 400_000;
+    let spi = Spi::new_blocking(sd.spi, sd.clk, sd.mosi, sd.miso, config.clone());
+    let cs = Output::new(sd.cs, Level::High);
+    let det = Input::new(sd.det, Pull::None);
+
+    let device = ExclusiveDevice::new(spi, cs, Delay).unwrap();
+    let sdcard = SdmmcSdCard::new(device, Delay);
+
+    config.frequency = 32_000_000;
+    sdcard.spi(|dev| dev.bus_mut().set_config(&config));
+    SDCARD.get().lock().await.replace(SdCard::new(sdcard, det));
+}
+
+#[embassy_executor::task]
+async fn kernel_task(
+    spawner: Spawner,
+    watchdog: Peri<'static, WATCHDOG>,
+    display: Display,
+    audio: Audio,
+    sd: Sd,
+    // _psram: Psram,
+    mcu: Mcu,
+    usb: Peri<'static, USB>,
+) {
+    spawner
+        .spawn(watchdog_task(Watchdog::new(watchdog)))
+        .unwrap();
+
+    #[cfg(feature = "defmt")]
+    defmt::info!("Clock: {}", embassy_rp::clocks::clk_sys_freq());
+
+    setup_mcu(mcu).await;
+
+    #[cfg(feature = "defmt")]
+    defmt::info!("setting up psram");
+    Timer::after_millis(100).await;
+
+    // setup_psram(psram).await;
+    #[cfg(feature = "psram")]
+    setup_qmi_psram().await;
+
+    Timer::after_millis(100).await;
+    setup_display(display, spawner).await;
+    setup_sd(sd).await;
+
+    spawner.spawn(audio_handler(audio)).unwrap();
+
+    let _usb = embassy_rp_usb::Driver::new(usb, Irqs);
+    // spawner.spawn(usb_handler(usb)).unwrap();
+
+    loop {
+        let ui_enabled = ENABLE_UI.load(Ordering::Relaxed);
+        if ui_enabled {
+            select(join(ui_handler(), prog_search_handler()), UI_CHANGE.wait()).await;
+        } else {
+            select(key_handler(), UI_CHANGE.wait()).await;
+        }
+    }
+}
+
+async fn prog_search_handler() {
+    loop {
+        {
+            let mut guard = SDCARD.get().lock().await;
+            let sd = guard.as_mut().unwrap();
+
+            let mut files = sd.list_files_by_extension(".bin").unwrap();
+            files.sort();
+            let mut select = SELECTIONS.lock().await;
+
+            if *select.selections() != files {
+                select.update_selections(files);
+                select.reset();
+            }
+        }
+        Timer::after_secs(5).await;
+    }
+}
+
+async fn key_handler() {
+    loop {
+        if let Some(event) = read_keyboard_fifo().await {
             unsafe {
                 let _ = KEY_CACHE.enqueue(event);
             }
         }
+        Timer::after_millis(50).await;
     }
 }

kernel/src/peripherals/keyboard.rs

@@ -1,5 +1,5 @@
 use crate::peripherals::PERIPHERAL_BUS;
-pub use shared::keyboard::{KeyCode, KeyEvent, KeyState, Modifiers};
+pub use userlib_sys::keyboard::{KeyCode, KeyEvent, KeyState, Modifiers};
 
 const REG_ID_KEY: u8 = 0x04;
 const REG_ID_FIF: u8 = 0x09;

kernel/src/psram.rs

@@ -0,0 +1,618 @@
+// This whole file was taken from
+// <https://github.com/wezterm/picocalc-wezterm/blob/8dcf8aae0598afdeaf0ed2ba50c39dea6e30c011/src/psram.rs>
+//
+use crate::Irqs;
+use embassy_futures::yield_now;
+use embassy_rp::Peri;
+use embassy_rp::clocks::clk_peri_freq;
+use embassy_rp::gpio::{Drive, SlewRate};
+use embassy_rp::peripherals::{DMA_CH3, DMA_CH4, PIN_2, PIN_3, PIN_20, PIN_21, PIO0};
+use embassy_rp::pio::program::pio_asm;
+use embassy_rp::pio::{Config, Direction, Pio, ShiftDirection};
+use embassy_rp::pio_programs::clock_divider::calculate_pio_clock_divider;
+use embassy_time::{Duration, Instant, Timer};
+
+// The physical connections in the picocalc schematic are:
+// LABEL     PICO      ESP-PSRAM64H
+// RAM_CS  - PIN_20    CE                    (pulled up to 3v3 via 10kOhm)
+// RAM_SCK - PIN_21    SCLK
+// RAM_TX  - PIN_2     SI/SIO0
+// RAM_RX  - PIN_3     SO/SIO1
+// RAM_IO2 - PIN_4     SIO2     (QPI Mode)
+// RAM_IO3 - PIN_5     SIO3     (QPI Mode)
+
+#[allow(unused)]
+const PSRAM_CMD_QUAD_END: u8 = 0xf5;
+#[allow(unused)]
+const PSRAM_CMD_QUAD_ENABLE: u8 = 0x35;
+#[allow(unused)]
+const PSRAM_CMD_READ_ID: u8 = 0x9F;
+const PSRAM_CMD_RSTEN: u8 = 0x66;
+const PSRAM_CMD_RST: u8 = 0x99;
+const PSRAM_CMD_WRITE: u8 = 0x02;
+const PSRAM_CMD_FAST_READ: u8 = 0x0B;
+#[allow(unused)]
+const PSRAM_CMD_QUAD_READ: u8 = 0xEB;
+#[allow(unused)]
+const PSRAM_CMD_QUAD_WRITE: u8 = 0x38;
+#[allow(unused)]
+const PSRAM_CMD_NOOP: u8 = 0xFF;
+#[allow(unused)]
+const PSRAM_KNOWN_GOOD_DIE_PASS: u8 = 0x5d;
+
+const MAX_PSRAM_FREQ: u32 = 133_000_000;
+
+pub struct PsRam {
+    sm: embassy_rp::pio::StateMachine<'static, PIO0, 0>,
+    tx_ch: Peri<'static, DMA_CH3>,
+    rx_ch: Peri<'static, DMA_CH4>,
+    pub size: u32,
+}
+
+impl PsRam {
+    pub async fn send_command(&mut self, cmd: &[u8], out: &mut [u8]) {
+        if out.is_empty() {
+            self.sm
+                .tx()
+                .dma_push(self.tx_ch.reborrow(), cmd, false)
+                .await;
+        } else {
+            let (rx, tx) = self.sm.rx_tx();
+            tx.dma_push(self.tx_ch.reborrow(), cmd, false).await;
+            rx.dma_pull(self.rx_ch.reborrow(), out, false).await;
+        }
+    }
+
+    pub async fn write(&mut self, mut addr: u32, mut data: &[u8]) {
+        // I haven't seen this work reliably over 24 bytes
+        const MAX_CHUNK: usize = 24;
+        while data.len() > 0 {
+            let to_write = data.len().min(MAX_CHUNK);
+            //defmt::info!("writing {to_write} @ {addr}");
+
+            #[rustfmt::skip]
+            let mut to_send = [
+                32 + (to_write as u8 * 8), // write address + data
+                0,                         // read 0 bits
+                PSRAM_CMD_WRITE,
+                ((addr >> 16) & 0xff) as u8,
+                ((addr >> 8) & 0xff) as u8,
+                (addr & 0xff) as u8,
+                // This sequence must be MAX_CHUNK in length
+                0, 0, 0, 0,
+                0, 0, 0, 0,
+                0, 0, 0, 0,
+                0, 0, 0, 0,
+                0, 0, 0, 0,
+                0, 0, 0, 0,
+            ];
+
+            for (src, dst) in data.iter().zip(to_send.iter_mut().skip(6)) {
+                *dst = *src;
+            }
+
+            self.send_command(&to_send[0..6 + to_write], &mut []).await;
+            addr += to_write as u32;
+            data = &data[to_write..];
+        }
+    }
+
+    pub async fn read_id(&mut self) -> [u8; 3] {
+        let mut id = [0u8; 3];
+        #[rustfmt::skip]
+        self.send_command(
+            &[
+                32,    // write 32 bits
+                3 * 8, // read 8 bytes = 64 bits
+                PSRAM_CMD_READ_ID,
+                // don't care: 24-bit "address"
+                0, 0, 0,
+            ],
+            &mut id,
+        )
+        .await;
+        id
+    }
+
+    pub async fn read(&mut self, mut addr: u32, mut out: &mut [u8]) {
+        // Cannot get reliable reads above 4 bytes at a time.
+        // out[4] will always have a bit error
+        const MAX_CHUNK: usize = 4;
+        while out.len() > 0 {
+            let to_read = out.len().min(MAX_CHUNK);
+            //defmt::info!("reading {to_read} @ {addr}");
+            self.send_command(
+                &[
+                    40,                // write 40 bits
+                    to_read as u8 * 8, // read n bytes
+                    PSRAM_CMD_FAST_READ,
+                    ((addr >> 16) & 0xff) as u8,
+                    ((addr >> 8) & 0xff) as u8,
+                    (addr & 0xff) as u8,
+                    0, // 8 cycle delay by sending 8 bits of don't care data
+                ],
+                &mut out[0..to_read],
+            )
+            .await;
+            addr += to_read as u32;
+            out = &mut out[to_read..];
+        }
+    }
+
+    #[allow(unused)]
+    pub async fn write8(&mut self, addr: u32, data: u8) {
+        //defmt::info!("write8 addr {addr} <- {data:x}");
+        self.send_command(
+            &[
+                40, // write 40 bits
+                0,  // read 0 bits
+                PSRAM_CMD_WRITE,
+                ((addr >> 16) & 0xff) as u8,
+                ((addr >> 8) & 0xff) as u8,
+                (addr & 0xff) as u8,
+                data,
+            ],
+            &mut [],
+        )
+        .await;
+    }
+
+    #[allow(unused)]
+    pub async fn read8(&mut self, addr: u32) -> u8 {
+        let mut buf = [0u8];
+        self.send_command(
+            &[
+                40, // write 40 bits
+                8,  // read 8 bits
+                PSRAM_CMD_FAST_READ,
+                ((addr >> 16) & 0xff) as u8,
+                ((addr >> 8) & 0xff) as u8,
+                (addr & 0xff) as u8,
+                0, // 8 cycle delay
+            ],
+            &mut buf,
+        )
+        .await;
+        buf[0]
+    }
+}
+
+pub async fn init_psram(
+    pio: Peri<'static, PIO0>,
+    sclk: Peri<'static, PIN_21>,
+    mosi: Peri<'static, PIN_2>,
+    miso: Peri<'static, PIN_3>,
+    cs: Peri<'static, PIN_20>,
+    dma1: Peri<'static, DMA_CH3>,
+    dma2: Peri<'static, DMA_CH4>,
+) -> PsRam {
+    let mut pio = Pio::new(pio, Irqs);
+
+    let divider = calculate_pio_clock_divider(MAX_PSRAM_FREQ);
+
+    // This pio program was taken from
+    // <https://github.com/polpo/rp2040-psram/blob/7786c93ec8d02dbb4f94a2e99645b25fb4abc2db/psram_spi.pio>
+    // which is Copyright © 2023 Ian Scott, reproduced here under the MIT license
+
+    let p = pio_asm!(
+        r#"
+.side_set 2                        ; sideset bit 1 is SCK, bit 0 is CS
+begin:
+    out x, 8            side 0b01  ; x = number of bits to output. CS deasserted
+    out y, 8            side 0b01  ; y = number of bits to input
+    jmp x--, writeloop  side 0b01  ; Pre-decement x by 1 so loop has correct number of iterations
+writeloop:
+    out pins, 1         side 0b00  ; Write value on pin, lower clock. CS asserted
+    jmp x--, writeloop  side 0b10  ; Raise clock: this is when PSRAM reads the value. Loop if we have more to write
+    jmp !y,  done       side 0b00  ; If this is a write-only operation, jump back to beginning
+    nop                 side 0b10  ; Fudge factor of extra clock cycle; the PSRAM needs 1 extra for output to start appearing
+    jmp readloop_mid    side 0b00  ; Jump to middle of readloop to decrement y and get right clock phase
+readloop:
+    in pins, 1          side 0b00  ; Read value on pin, lower clock. Datasheet says to read on falling edge > 83MHz
+readloop_mid:
+    jmp y--, readloop   side 0b10  ; Raise clock. Loop if we have more to read
+done:
+    nop                 side 0b11  ; CS deasserted
+    "#
+    );
+    let prog = pio.common.load_program(&p.program);
+
+    let mut cfg = Config::default();
+
+    let mut cs = pio.common.make_pio_pin(cs);
+    let mut sclk = pio.common.make_pio_pin(sclk);
+    let mut mosi = pio.common.make_pio_pin(mosi);
+    let mut miso = pio.common.make_pio_pin(miso);
+
+    sclk.set_slew_rate(SlewRate::Fast);
+    mosi.set_slew_rate(SlewRate::Fast);
+
+    cs.set_drive_strength(Drive::_4mA);
+    sclk.set_drive_strength(Drive::_4mA);
+    mosi.set_drive_strength(Drive::_4mA);
+    miso.set_drive_strength(Drive::_4mA);
+
+    cfg.use_program(&prog, &[&cs, &sclk]);
+    cfg.set_out_pins(&[&mosi]);
+    cfg.set_in_pins(&[&miso]);
+
+    cfg.shift_out.direction = ShiftDirection::Left;
+    cfg.shift_out.auto_fill = true;
+    cfg.shift_out.threshold = 8;
+
+    cfg.shift_in = cfg.shift_out;
+    cfg.clock_divider = divider;
+
+    let mut sm = pio.sm0;
+    sm.restart();
+    sm.set_pin_dirs(Direction::Out, &[&cs, &sclk]);
+    sm.set_pin_dirs(Direction::Out, &[&mosi]);
+    sm.set_pin_dirs(Direction::In, &[&miso]);
+    miso.set_input_sync_bypass(true);
+
+    sm.set_config(&cfg);
+    sm.set_enable(true);
+
+    let mut psram = PsRam {
+        sm,
+        tx_ch: dma1,
+        rx_ch: dma2,
+        size: 0,
+    };
+
+    // Issue a reset command
+    psram.send_command(&[8, 0, PSRAM_CMD_RSTEN], &mut []).await;
+    Timer::after(Duration::from_micros(50)).await;
+    psram.send_command(&[8, 0, PSRAM_CMD_RST], &mut []).await;
+    Timer::after(Duration::from_micros(100)).await;
+
+    #[cfg(feature = "defmt")]
+    defmt::info!("Verifying 1 byte write and read...");
+    for i in 0..10u8 {
+        psram.write8(i as u32, i).await;
+    }
+    for i in 0..10u32 {
+        let n = psram.read8(i as u32).await;
+        if n as u32 != i {}
+    }
+    #[cfg(feature = "defmt")]
+    defmt::info!("testing read again @ 0");
+    let mut got = [0u8; 8];
+    psram.read(0, &mut got).await;
+    const EXPECT: &[u8] = &[0, 1, 2, 3, 4, 5, 6, 7];
+    if got != EXPECT {
+        #[cfg(feature = "defmt")]
+        defmt::warn!("Got Read error");
+    }
+
+    const DEADBEEF: &[u8] = &[0xd, 0xe, 0xa, 0xd, 0xb, 0xe, 0xe, 0xf];
+    #[cfg(feature = "defmt")]
+    defmt::info!("testing write of deadbeef at 0");
+    psram.write(0, DEADBEEF).await;
+
+    #[cfg(feature = "defmt")]
+    defmt::info!("testing read of deadbeef from 0");
+    psram.read(0, &mut got).await;
+    if got != DEADBEEF {
+        for addr in 0..DEADBEEF.len() {
+            let bad = got[addr];
+            if bad != DEADBEEF[addr] {
+                let x = psram.read8(addr as u32).await;
+                #[cfg(feature = "defmt")]
+                defmt::info!("read addr: {}, got: {:X}", addr, x);
+            }
+        }
+    }
+
+    const TEST_STRING: &[u8] = b"hello there, this is a test, how is it?";
+    psram.write(16, TEST_STRING).await;
+
+    let mut buffer = [0u8; 42];
+    psram.read(16, &mut buffer).await;
+
+    let got = &buffer[0..TEST_STRING.len()];
+
+    if got != TEST_STRING {}
+
+    #[cfg(feature = "defmt")]
+    defmt::info!("PSRAM test complete");
+
+    let id = psram.read_id().await;
+    #[cfg(feature = "defmt")]
+    defmt::info!("psram id: {}", id);
+    // id: [d, 5d, 53, 15, 49, e3, 7c, 7b]
+    // id[0] -- manufacturer id
+    // id[1] -- "known good die" status
+    if id[1] == PSRAM_KNOWN_GOOD_DIE_PASS {
+        // See <https://github.com/espressif/esp-idf/blob/1c468f68259065ef51afd114605d9122f13d9d72/components/esp_psram/esp32/esp_psram_impl_quad.c#L67-L86>
+        // for information on deciding the size of ESP PSRAM chips,
+        // such as the one used in the picocalc
+        let size = match (id[2] >> 5) & 0x7 {
+            0 => 16,
+            1 => 32,
+            2 => 64,
+            _ => 0,
+        };
+        psram.size = size * 1024 * 1024 / 8;
+    }
+
+    psram
+}
+
+#[allow(unused)]
+pub async fn test_psram(psram: &mut PsRam) -> bool {
+    const REPORT_CHUNK: u32 = 256 * 1024;
+    const BLOCK_SIZE: usize = 8;
+    let limit = psram.size; //.min(4 * 1024 * 1024);
+
+    let start = Instant::now();
+
+    fn expect(addr: u32) -> [u8; BLOCK_SIZE] {
+        [
+            !((addr >> 24 & 0xff) as u8),
+            !((addr >> 16 & 0xff) as u8),
+            !((addr >> 8 & 0xff) as u8),
+            !((addr & 0xff) as u8),
+            ((addr >> 24 & 0xff) as u8),
+            ((addr >> 16 & 0xff) as u8),
+            ((addr >> 8 & 0xff) as u8),
+            ((addr & 0xff) as u8),
+        ]
+    }
+
+    for i in 0..limit / BLOCK_SIZE as u32 {
+        let addr = i * BLOCK_SIZE as u32;
+        let data = expect(addr);
+        psram.write(addr, &data).await;
+        if addr > 0 && addr % REPORT_CHUNK == 0 {
+            if start.elapsed() > Duration::from_secs(5) {}
+        }
+        // Yield so that the watchdog doesn't kick in
+        yield_now().await;
+    }
+    let writes_took = start.elapsed();
+
+    #[cfg(feature = "defmt")]
+    defmt::info!("Starting reads...");
+    Timer::after(Duration::from_millis(200)).await;
+
+    let start = Instant::now();
+    let mut bad_count = 0;
+    let mut data = [0u8; BLOCK_SIZE];
+    for i in 0..limit / BLOCK_SIZE as u32 {
+        let addr = i * BLOCK_SIZE as u32;
+        let expect = expect(addr);
+        psram.read(addr, &mut data).await;
+        if addr == 0 {
+            Timer::after(Duration::from_millis(200)).await;
+        }
+        if data != expect {
+            bad_count += 1;
+            if bad_count < 50 {}
+        }
+        if addr > 0 && addr % REPORT_CHUNK == 0 {
+            if start.elapsed() > Duration::from_secs(5) {}
+        }
+
+        // Yield so that the watchdog doesn't kick in
+        yield_now().await;
+    }
+    let reads_took = start.elapsed();
+
+    bad_count == 0
+}
+
+// The origin of the code in this file is:
+// <https://github.com/Altaflux/rp2350-psram-test/blob/ae50a819fef96486f6d962a609984cde4b4dd4cc/src/psram.rs#L1>
+// which is MIT/Apache-2 licensed.
+#[unsafe(link_section = ".data")]
+#[inline(never)]
+pub fn detect_psram_qmi(qmi: &embassy_rp::pac::qmi::Qmi) -> u32 {
+    const GPIO_FUNC_XIP_CS1: u8 = 9;
+    const XIP_CS_PIN: usize = 47;
+    embassy_rp::pac::PADS_BANK0.gpio(XIP_CS_PIN).modify(|w| {
+        w.set_iso(true);
+    });
+    embassy_rp::pac::PADS_BANK0.gpio(XIP_CS_PIN).modify(|w| {
+        w.set_ie(true);
+        w.set_od(false);
+    });
+    embassy_rp::pac::IO_BANK0
+        .gpio(XIP_CS_PIN)
+        .ctrl()
+        .write(|w| w.set_funcsel(GPIO_FUNC_XIP_CS1));
+    embassy_rp::pac::PADS_BANK0.gpio(XIP_CS_PIN).modify(|w| {
+        w.set_iso(false);
+    });
+
+    critical_section::with(|_cs| {
+        // Try and read the PSRAM ID via direct_csr.
+        qmi.direct_csr().write(|w| {
+            w.set_clkdiv(30);
+            w.set_en(true);
+        });
+
+        // Need to poll for the cooldown on the last XIP transfer to expire
+        // (via direct-mode BUSY flag) before it is safe to perform the first
+        // direct-mode operation
+        while qmi.direct_csr().read().busy() {
+            // rp235x_hal::arch::nop();
+        }
+
+        // Exit out of QMI in case we've inited already
+        qmi.direct_csr().modify(|w| w.set_assert_cs1n(true));
+
+        // Transmit the command to exit QPI quad mode - read ID as standard SPI
+        // Transmit as quad.
+        qmi.direct_tx().write(|w| {
+            w.set_oe(true);
+            w.set_iwidth(embassy_rp::pac::qmi::vals::Iwidth::Q);
+            w.set_data(PSRAM_CMD_QUAD_END.into());
+        });
+
+        while qmi.direct_csr().read().busy() {
+            // rp235x_hal::arch::nop();
+        }
+
+        let _ = qmi.direct_rx().read();
+
+        qmi.direct_csr().modify(|w| {
+            w.set_assert_cs1n(false);
+        });
+
+        // Read the id
+        qmi.direct_csr().modify(|w| {
+            w.set_assert_cs1n(true);
+        });
+
+        // kgd is "known good die"
+        let mut kgd: u16 = 0;
+        let mut eid: u16 = 0;
+        for i in 0usize..7 {
+            qmi.direct_tx().write(|w| {
+                w.set_data(if i == 0 {
+                    PSRAM_CMD_READ_ID.into()
+                } else {
+                    PSRAM_CMD_NOOP.into()
+                })
+            });
+
+            while !qmi.direct_csr().read().txempty() {
+                // rp235x_hal::arch::nop();
+            }
+
+            while qmi.direct_csr().read().busy() {
+                // rp235x_hal::arch::nop();
+            }
+
+            let value = qmi.direct_rx().read().direct_rx();
+            match i {
+                5 => {
+                    kgd = value;
+                }
+                6 => {
+                    eid = value;
+                }
+                _ => {}
+            }
+        }
+
+        qmi.direct_csr().modify(|w| {
+            w.set_assert_cs1n(false);
+            w.set_en(false);
+        });
+        let mut param_size: u32 = 0;
+        if kgd == PSRAM_KNOWN_GOOD_DIE_PASS as u16 {
+            param_size = 1024 * 1024;
+            let size_id = eid >> 5;
+            if eid == 0x26 || size_id == 2 {
+                param_size *= 8;
+            } else if size_id == 0 {
+                param_size *= 2;
+            } else if size_id == 1 {
+                param_size *= 4;
+            }
+        }
+        param_size
+    })
+}
+
+#[unsafe(link_section = ".data")]
+#[inline(never)]
+pub fn init_psram_qmi(
+    qmi: &embassy_rp::pac::qmi::Qmi,
+    xip: &embassy_rp::pac::xip_ctrl::XipCtrl,
+) -> u32 {
+    let psram_size = detect_psram_qmi(qmi);
+
+    if psram_size == 0 {
+        #[cfg(feature = "defmt")]
+        defmt::error!("qmi psram size 0");
+        return 0;
+    }
+
+    let clock_hz = clk_peri_freq();
+
+    let mut divisor: u32 = (clock_hz + MAX_PSRAM_FREQ - 1) / MAX_PSRAM_FREQ;
+    if divisor == 1 && clock_hz > 100_000_000 {
+        divisor = 2;
+    }
+    let mut rxdelay: u32 = divisor;
+    if clock_hz / divisor > 100_000_000 {
+        rxdelay += 1;
+    }
+
+    // - Max select must be <= 8us.  The value is given in multiples of 64 system clocks.
+    // - Min deselect must be >= 18ns.  The value is given in system clock cycles - ceil(divisor / 2).
+    let clock_period_fs: u64 = 1_000_000_000_000_000_u64 / u64::from(clock_hz);
+    let max_select: u8 = ((125 * 1_000_000) / clock_period_fs) as u8;
+    let min_deselect: u32 = ((18 * 1_000_000 + (clock_period_fs - 1)) / clock_period_fs
+        - u64::from(divisor + 1) / 2) as u32;
+
+    // #[cfg(feature = "defmt")]
+    // defmt::info!(
+    //     "clock_period_fs={} max_select={} min_deselect={}",
+    //     clock_period_fs,
+    //     max_select,
+    //     min_deselect
+    // );
+
+    qmi.direct_csr().write(|w| {
+        w.set_clkdiv(10);
+        w.set_en(true);
+        w.set_auto_cs1n(true);
+    });
+
+    while qmi.direct_csr().read().busy() {
+        // rp235x_hal::arch::nop();
+    }
+
+    qmi.direct_tx().write(|w| {
+        w.set_nopush(true);
+        w.0 = 0x35;
+    });
+
+    while qmi.direct_csr().read().busy() {
+        // rp235x_hal::arch::nop();
+    }
+
+    qmi.mem(1).timing().write(|w| {
+        w.set_cooldown(1);
+        w.set_pagebreak(embassy_rp::pac::qmi::vals::Pagebreak::_1024);
+        w.set_max_select(max_select as u8);
+        w.set_min_deselect(min_deselect as u8);
+        w.set_rxdelay(rxdelay as u8);
+        w.set_clkdiv(divisor as u8);
+    });
+
+    // // Set PSRAM commands and formats
+    qmi.mem(1).rfmt().write(|w| {
+        w.set_prefix_width(embassy_rp::pac::qmi::vals::PrefixWidth::Q);
+        w.set_addr_width(embassy_rp::pac::qmi::vals::AddrWidth::Q);
+        w.set_suffix_width(embassy_rp::pac::qmi::vals::SuffixWidth::Q);
+        w.set_dummy_width(embassy_rp::pac::qmi::vals::DummyWidth::Q);
+        w.set_data_width(embassy_rp::pac::qmi::vals::DataWidth::Q);
+        w.set_prefix_len(embassy_rp::pac::qmi::vals::PrefixLen::_8);
+        w.set_dummy_len(embassy_rp::pac::qmi::vals::DummyLen::_24);
+    });
+
+    qmi.mem(1).rcmd().write(|w| w.0 = 0xEB);
+
+    qmi.mem(1).wfmt().write(|w| {
+        w.set_prefix_width(embassy_rp::pac::qmi::vals::PrefixWidth::Q);
+        w.set_addr_width(embassy_rp::pac::qmi::vals::AddrWidth::Q);
+        w.set_suffix_width(embassy_rp::pac::qmi::vals::SuffixWidth::Q);
+        w.set_dummy_width(embassy_rp::pac::qmi::vals::DummyWidth::Q);
+        w.set_data_width(embassy_rp::pac::qmi::vals::DataWidth::Q);
+        w.set_prefix_len(embassy_rp::pac::qmi::vals::PrefixLen::_8);
+    });
+
+    qmi.mem(1).wcmd().write(|w| w.0 = 0x38);
+
+    // Disable direct mode
+    qmi.direct_csr().write(|w| w.0 = 0);
+
+    // Enable writes to PSRAM
+    xip.ctrl().modify(|w| w.set_writable_m1(true));
+    psram_size
+}

kernel/src/scsi/mod.rs

@@ -1,7 +1,9 @@
-use crate::format;
+use embassy_futures::select::select;
+use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
+use embassy_sync::lazy_lock::LazyLock;
+use embassy_sync::signal::Signal;
+use embassy_usb::Builder;
 use embassy_usb::driver::{Driver, EndpointIn, EndpointOut};
-use embassy_usb::types::StringIndex;
-use embassy_usb::{Builder, Config};
 use embedded_sdmmc::{Block, BlockIdx};
 use heapless::Vec;
 
@@ -12,13 +14,24 @@ use crate::storage::{SDCARD, SdCard};
 
 const BULK_ENDPOINT_PACKET_SIZE: usize = 64;
 
+pub static MSC_SHUTDOWN: Signal<CriticalSectionRawMutex, ()> = Signal::new();
+
+// number of blocks to read from sd at once
+// higher is better, but is larger. Size is BLOCKS * 512 bytes
+const BLOCKS: usize = 32;
+static mut BLOCK_BUF: LazyLock<[Block; BLOCKS]> =
+    LazyLock::new(|| core::array::from_fn(|_| Block::new()));
+
 pub struct MassStorageClass<'d, D: Driver<'d>> {
+    temp_sd: Option<SdCard>, // temporary owns sdcard when scsi is running
+    ejected: bool,
+    pending_eject: bool,
     bulk_out: D::EndpointOut,
     bulk_in: D::EndpointIn,
 }
 
-impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
+impl<'d, D: Driver<'d>> MassStorageClass<'d, D> {
-    pub fn new(builder: &mut Builder<'d, D>) -> Self {
+    pub fn new(builder: &mut Builder<'d, D>, temp_sd: Option<SdCard>) -> Self {
         let mut function = builder.function(0x08, SUBCLASS_SCSI, 0x50); // Mass Storage class
         let mut interface = function.interface();
         let mut alt = interface.alt_setting(0x08, SUBCLASS_SCSI, 0x50, None);
@@ -26,37 +39,75 @@ impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
         let bulk_out = alt.endpoint_bulk_out(None, BULK_ENDPOINT_PACKET_SIZE as u16);
         let bulk_in = alt.endpoint_bulk_in(None, BULK_ENDPOINT_PACKET_SIZE as u16);
 
-        Self { bulk_out, bulk_in }
+        Self {
+            temp_sd,
+            pending_eject: false,
+            ejected: false,
+            bulk_out,
+            bulk_in,
+        }
     }
 
     pub async fn poll(&mut self) {
         loop {
-            let mut cbw_buf = [0u8; 31];
+            if !self.ejected {
-            if let Ok(n) = self.bulk_out.read(&mut cbw_buf).await {
+                select(self.handle_cbw(), MSC_SHUTDOWN.wait()).await;
-                if n == 31 {
+
-                    if let Some(cbw) = CommandBlockWrapper::parse(&cbw_buf[..n]) {
+                if MSC_SHUTDOWN.signaled() {
-                        // TODO: validate cbw
+                    #[cfg(feature = "defmt")]
-                        if self.handle_command(&cbw.CBWCB).await.is_ok() {
+                    defmt::info!("MSC shutting down");
-                            self.send_csw_success(cbw.dCBWTag).await
+
-                        } else {
+                    if self.temp_sd.is_some() {
-                            self.send_csw_fail(cbw.dCBWTag).await
+                        let mut guard = SDCARD.get().lock().await;
-                        }
+                        guard.replace(self.temp_sd.take().unwrap()).unwrap();
                     }
+
+                    self.ejected = true;
+
+                    return;
                 }
             }
         }
     }
 
-    async fn handle_command(&mut self, cbw: &[u8]) -> Result<(), ()> {
+    async fn handle_cbw(&mut self) {
-        let mut response: Vec<u8, BULK_ENDPOINT_PACKET_SIZE> = Vec::new();
+        let mut cbw_buf = [0u8; 31];
-        let mut block = [Block::new(); 1];
+        if let Ok(n) = self.bulk_out.read(&mut cbw_buf).await
-
+            && n == 31
-        match parse_cb(cbw) {
+            && let Some(cbw) = CommandBlockWrapper::parse(&cbw_buf[..n])
-            ScsiCommand::Unknown => {
+        {
-                #[cfg(feature = "defmt")]
+            // Take sdcard to increase speed
-                defmt::warn!("Got unexpected scsi command: {}", cbw);
+            if self.temp_sd.is_none() {
-                Err(())
+                let mut guard = SDCARD.get().lock().await;
+                if let Some(sd) = guard.take() {
+                    self.temp_sd = Some(sd);
+                } else {
+                    #[cfg(feature = "defmt")]
+                    defmt::warn!("Tried to take SDCARD but it was already taken");
+                    return;
+                }
             }
+
+            let command = parse_cb(&cbw.CBWCB);
+            if self.handle_command(command).await.is_ok() {
+                self.send_csw_success(cbw.dCBWTag).await
+            } else {
+                self.send_csw_fail(cbw.dCBWTag).await
+            }
+
+            if self.pending_eject
+                && let ScsiCommand::Write { lba: _, len: _ } = command
+            {
+                MSC_SHUTDOWN.signal(());
+            }
+        }
+    }
+
+    async fn handle_command(&mut self, command: ScsiCommand) -> Result<(), ()> {
+        let mut response: Vec<u8, BULK_ENDPOINT_PACKET_SIZE> = Vec::new();
+
+        match command {
+            ScsiCommand::Unknown => Err(()),
             ScsiCommand::Inquiry {
                 evpd,
                 page_code,
@@ -134,20 +185,21 @@ impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
                 self.bulk_in.write(&response[..len]).await.map_err(|_| ())
             }
             ScsiCommand::TestUnitReady => {
-                let guard = SDCARD.get().lock().await;
+                if self.temp_sd.as_ref().unwrap().is_attached() {
-                let sdcard = guard.as_ref().unwrap();
-                if sdcard.is_attached() {
                     Ok(())
                 } else {
                     Err(())
                 }
             }
-            ScsiCommand::RequestSense { desc, alloc_len } => Ok(()),
+            ScsiCommand::RequestSense {
+                desc: _,
+                alloc_len: _,
+            } => Ok(()),
             ScsiCommand::ModeSense6 {
-                dbd,
+                dbd: _,
-                page_control,
+                page_control: _,
-                page_code,
+                page_code: _,
-                subpage_code,
+                subpage_code: _,
                 alloc_len,
             } => {
                 // DBD=0, no block descriptors; total length = 4
@@ -163,10 +215,10 @@ impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
                 self.bulk_in.write(&response[..len]).await.map_err(|_| ())
             }
             ScsiCommand::ModeSense10 {
-                dbd,
+                dbd: _,
-                page_control,
+                page_control: _,
-                page_code,
+                page_code: _,
-                subpage_code,
+                subpage_code: _,
                 alloc_len,
             } => {
                 let response = [
@@ -182,13 +234,10 @@ impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
                 self.bulk_in.write(&response[..len]).await.map_err(|_| ())
             }
             ScsiCommand::ReadCapacity10 => {
-                let guard = SDCARD.get().lock().await;
-                let sdcard = guard.as_ref().unwrap();
-
                 let block_size = SdCard::BLOCK_SIZE as u64;
-                let total_blocks = sdcard.size() / block_size;
+                let total_blocks = self.temp_sd.as_ref().unwrap().size() / block_size;
 
-                let last_lba = total_blocks.checked_sub(1).unwrap_or(0);
+                let last_lba = total_blocks.saturating_sub(1);
 
                 response.extend_from_slice(&(last_lba as u32).to_be_bytes())?;
                 response.extend_from_slice(&(block_size as u32).to_be_bytes())?;
@@ -196,13 +245,10 @@ impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
                 self.bulk_in.write(&response).await.map_err(|_| ())
             }
             ScsiCommand::ReadCapacity16 { alloc_len } => {
-                let guard = SDCARD.get().lock().await;
-                let sdcard = guard.as_ref().unwrap();
-
                 let block_size = SdCard::BLOCK_SIZE as u64;
-                let total_blocks = sdcard.size() / block_size;
+                let total_blocks = self.temp_sd.as_ref().unwrap().size() / block_size;
 
-                let last_lba = total_blocks.checked_sub(1).unwrap_or(0);
+                let last_lba = total_blocks.saturating_sub(1);
 
                 response.extend_from_slice(&last_lba.to_be_bytes())?; // 8 bytes last LBA
                 response.extend_from_slice(&(block_size as u32).to_be_bytes())?; // 4 bytes block length
@@ -212,40 +258,78 @@ impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
                 self.bulk_in.write(&response[..len]).await.map_err(|_| ())
             }
             ScsiCommand::Read { lba, len } => {
-                let guard = SDCARD.get().lock().await;
+                let sdcard = self.temp_sd.as_ref().unwrap();
-                let sdcard = guard.as_ref().unwrap();
+                let block_buf = unsafe { &mut *BLOCK_BUF.get_mut() };
+                let mut blocks = len;
+                let mut idx = lba;
 
-                for i in 0..len {
+                while blocks > 0 {
-                    let block_idx = BlockIdx(lba as u32 + i as u32);
+                    if blocks >= block_buf.len() as u64 {
-                    sdcard.read_blocks(&mut block, block_idx)?;
+                        sdcard.read_blocks(block_buf, BlockIdx(idx as u32))?;
-                    for chunk in block[0].contents.chunks(BULK_ENDPOINT_PACKET_SIZE.into()) {
+
-                        self.bulk_in.write(chunk).await.map_err(|_| ())?;
+                        for block in &mut *block_buf {
+                            for chunk in block.contents.chunks(BULK_ENDPOINT_PACKET_SIZE) {
+                                self.bulk_in.write(chunk).await.map_err(|_| ())?;
+                            }
+                        }
+
+                        blocks -= block_buf.len() as u64;
+                        idx += block_buf.len() as u64;
+                    } else {
+                        sdcard
+                            .read_blocks(&mut block_buf[..blocks as usize], BlockIdx(idx as u32))?;
+
+                        for block in &block_buf[..blocks as usize] {
+                            for chunk in block.contents.chunks(BULK_ENDPOINT_PACKET_SIZE) {
+                                self.bulk_in.write(chunk).await.map_err(|_| ())?;
+                            }
+                        }
+
+                        idx += blocks;
+                        blocks = 0;
                     }
                 }
                 Ok(())
             }
             ScsiCommand::Write { lba, len } => {
-                let guard = SDCARD.get().lock().await;
+                let sdcard = self.temp_sd.as_ref().unwrap();
-                let sdcard = guard.as_ref().unwrap();
+                let block_buf = unsafe { &mut *BLOCK_BUF.get_mut() };
+                let mut blocks = len;
+                let mut idx = lba;
 
-                for i in 0..len {
+                while blocks > 0 {
-                    let block_idx = BlockIdx(lba as u32 + i as u32);
+                    if blocks >= block_buf.len() as u64 {
-                    for chunk in block[0]
+                        for block in block_buf.as_mut() {
-                        .contents
+                            for chunk in block.contents.chunks_mut(BULK_ENDPOINT_PACKET_SIZE) {
-                        .chunks_mut(BULK_ENDPOINT_PACKET_SIZE.into())
+                                self.bulk_out.read(chunk).await.map_err(|_| ())?;
-                    {
+                            }
-                        self.bulk_out.read(chunk).await.map_err(|_| ())?;
+                        }
+
+                        sdcard.read_blocks(block_buf, BlockIdx(idx as u32))?;
+
+                        blocks -= block_buf.len() as u64;
+                        idx += block_buf.len() as u64;
+                    } else {
+                        for block in block_buf[..blocks as usize].as_mut() {
+                            for chunk in block.contents.chunks_mut(BULK_ENDPOINT_PACKET_SIZE) {
+                                self.bulk_out.read(chunk).await.map_err(|_| ())?;
+                            }
+                        }
+
+                        sdcard.write_blocks(
+                            &mut block_buf[..blocks as usize],
+                            BlockIdx(idx as u32),
+                        )?;
+
+                        idx += blocks;
+                        blocks = 0;
                     }
-                    sdcard.write_blocks(&mut block, block_idx)?;
                 }
                 Ok(())
             }
             ScsiCommand::ReadFormatCapacities { alloc_len } => {
-                let guard = SDCARD.get().lock().await;
-                let sdcard = guard.as_ref().unwrap();
-
                 let block_size = SdCard::BLOCK_SIZE as u32;
-                let num_blocks = (sdcard.size() / block_size as u64) as u32;
+                let num_blocks = (self.temp_sd.as_ref().unwrap().size() / block_size as u64) as u32;
 
                 let mut response = [0u8; 12];
 
@@ -264,7 +348,12 @@ impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
                     .map_err(|_| ())
             }
             ScsiCommand::PreventAllowMediumRemoval { prevent: _prevent } => Ok(()),
-            ScsiCommand::StartStopUnit { start, load_eject } => Ok(()),
+            ScsiCommand::StartStopUnit { start, load_eject } => {
+                if !start && load_eject {
+                    self.pending_eject = true;
+                }
+                Ok(())
+            }
         }
     }
 
@@ -273,7 +362,8 @@ impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
     }
 
     pub async fn send_csw_fail(&mut self, tag: u32) {
-        defmt::error!("Command Failed");
+        #[cfg(feature = "defmt")]
+        defmt::error!("Command Failed: {}", tag);
         self.send_csw(tag, 0x01, 0).await; // 0x01 = Command Failed
     }
 
@@ -288,6 +378,7 @@ impl<'d, 's, D: Driver<'d>> MassStorageClass<'d, D> {
 }
 
 #[repr(C, packed)]
+#[allow(non_snake_case)]
 struct CommandBlockWrapper {
     dCBWSignature: u32,
     dCBWTag: u32,
@@ -298,6 +389,7 @@ struct CommandBlockWrapper {
     CBWCB: [u8; 16],
 }
 
+#[allow(non_snake_case)]
 impl CommandBlockWrapper {
     fn parse(buf: &[u8]) -> Option<Self> {
         if buf.len() < 31 {

kernel/src/scsi/scsi_types.rs

@@ -1,12 +1,7 @@
 use num_enum::TryFromPrimitive;
 
-#[derive(Debug, Clone, Copy)]
-pub enum ScsiError {
-    NotReady,
-}
-
 /// THE CODE BELOW ORIGINATES FROM: https://github.com/apohrebniak/usbd-storage/blob/master/usbd-storage/src/subclass/scsi.rs
-
+///
 /// SCSI device subclass code
 pub const SUBCLASS_SCSI: u8 = 0x06; // SCSI Transparent command set
 
@@ -96,6 +91,7 @@ pub enum ScsiCommand {
     },
 }
 
+#[allow(clippy::enum_variant_names)]
 #[repr(u8)]
 #[derive(Copy, Clone, Debug, TryFromPrimitive)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]

kernel/src/storage.rs

@@ -9,8 +9,8 @@ use embassy_sync::mutex::Mutex;
 use embassy_time::Delay;
 use embedded_hal_bus::spi::ExclusiveDevice;
 use embedded_sdmmc::{
-    Block, BlockCount, BlockDevice, BlockIdx, Directory, SdCard as SdmmcSdCard, TimeSource,
+    Block, BlockDevice, BlockIdx, Directory, SdCard as SdmmcSdCard, TimeSource, Timestamp,
-    Timestamp, Volume, VolumeIdx, VolumeManager, sdcard::Error,
+    VolumeIdx, VolumeManager, sdcard::Error,
 };
 use embedded_sdmmc::{File as SdFile, LfnBuffer, Mode, ShortFileName};
 
@@ -21,8 +21,7 @@ pub const MAX_VOLUMES: usize = 1;
 type Device = ExclusiveDevice<Spi<'static, SPI0, Blocking>, Output<'static>, embassy_time::Delay>;
 type SD = SdmmcSdCard<Device, Delay>;
 type VolMgr = VolumeManager<SD, DummyTimeSource, MAX_DIRS, MAX_FILES, MAX_VOLUMES>;
-type Vol<'a> = Volume<'a, SD, DummyTimeSource, MAX_DIRS, MAX_FILES, MAX_VOLUMES>;
+pub type Dir<'a> = Directory<'a, SD, DummyTimeSource, MAX_DIRS, MAX_FILES, MAX_VOLUMES>;
-type Dir<'a> = Directory<'a, SD, DummyTimeSource, MAX_DIRS, MAX_FILES, MAX_VOLUMES>;
 pub type File<'a> = SdFile<'a, SD, DummyTimeSource, MAX_DIRS, MAX_FILES, MAX_VOLUMES>;
 
 pub static SDCARD: LazyLock<Mutex<CriticalSectionRawMutex, Option<SdCard>>> =
@@ -35,12 +34,24 @@ impl TimeSource for DummyTimeSource {
     }
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, Eq)]
 pub struct FileName {
     pub long_name: String,
     pub short_name: ShortFileName,
 }
 
+impl PartialOrd for FileName {
+    fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for FileName {
+    fn cmp(&self, other: &Self) -> core::cmp::Ordering {
+        self.long_name.cmp(&other.long_name)
+    }
+}
+
 pub struct SdCard {
     det: Input<'static>,
     volume_mgr: VolMgr,
@@ -55,10 +66,7 @@ impl SdCard {
             DummyTimeSource {},
             5000,
         );
-        Self {
+        Self { det, volume_mgr }
-            det: det,
-            volume_mgr,
-        }
     }
 
     /// Returns true if an SD card is inserted.
@@ -78,17 +86,6 @@ impl SdCard {
         result
     }
 
-    pub fn num_blocks(&self) -> u32 {
-        let mut result = 0;
-
-        self.volume_mgr.device(|sd| {
-            result = sd.num_blocks().unwrap_or(BlockCount(0)).0;
-            DummyTimeSource {}
-        });
-
-        result
-    }
-
     pub fn read_blocks(&self, blocks: &mut [Block], start_block_idx: BlockIdx) -> Result<(), ()> {
         let mut res: Result<(), Error> = Ok(());
         self.volume_mgr.device(|sd| {
@@ -101,7 +98,7 @@ impl SdCard {
     pub fn write_blocks(&self, blocks: &mut [Block], start_block_idx: BlockIdx) -> Result<(), ()> {
         let mut res: Result<(), Error> = Ok(());
         self.volume_mgr.device(|sd| {
-            let res = sd.write(blocks, start_block_idx);
+            res = sd.write(blocks, start_block_idx);
             DummyTimeSource {}
         });
         res.map_err(|_| ())
@@ -114,16 +111,15 @@ impl SdCard {
         access(root_dir);
     }
 
-    pub async fn read_file(
+    pub async fn read_file<T>(
         &mut self,
         name: &ShortFileName,
-        mut access: impl FnMut(File),
+        mut access: impl FnMut(File) -> T,
-    ) -> Result<(), ()> {
+    ) -> Result<T, ()> {
         let mut res = Err(());
         self.access_root_dir(|root_dir| {
             if let Ok(file) = root_dir.open_file_in_dir(name, Mode::ReadOnly) {
-                res = Ok(());
+                res = Ok(access(file));
-                access(file);
             }
         });
 

kernel/src/syscalls.rs

@@ -0,0 +1,362 @@
+use alloc::{string::ToString, vec::Vec};
+use core::{ffi::c_char, ptr, sync::atomic::Ordering};
+use embassy_rp::clocks::{RoscRng, clk_sys_freq};
+use embassy_time::Instant;
+use embedded_graphics::draw_target::DrawTarget;
+use embedded_sdmmc::LfnBuffer;
+use heapless::spsc::Queue;
+use userlib_sys::{
+    AUDIO_BUFFER_SAMPLES, Alloc, AudioBufferReady, CLayout, CPixel, Dealloc, DrawIter, FileLen,
+    GenRand, GetMs, ListDir, Print, ReadFile, RngRequest, SendAudioBuffer, SleepMs, WriteFile,
+    keyboard::*,
+};
+
+#[cfg(feature = "psram")]
+use crate::heap::HEAP;
+
+#[cfg(feature = "psram")]
+use core::alloc::GlobalAlloc;
+
+use crate::{
+    audio::{AUDIO_BUFFER, AUDIO_BUFFER_READY, AUDIO_BUFFER_WRITTEN},
+    display::FRAMEBUFFER,
+    framebuffer::FB_PAUSED,
+    storage::{Dir, File, SDCARD},
+};
+
+const _: Alloc = alloc;
+pub extern "C" fn alloc(layout: CLayout) -> *mut u8 {
+    // SAFETY: caller guarantees layout is valid
+    unsafe {
+        #[cfg(feature = "psram")]
+        {
+            return HEAP.alloc(layout.into());
+        }
+
+        #[cfg(not(feature = "psram"))]
+        {
+            alloc::alloc::alloc(layout.into())
+        }
+    }
+}
+
+const _: Dealloc = dealloc;
+pub extern "C" fn dealloc(ptr: *mut u8, layout: CLayout) {
+    // SAFETY: caller guarantees ptr and layout are valid
+    #[cfg(feature = "psram")]
+    {
+        unsafe { HEAP.dealloc(ptr, layout.into()) }
+    }
+
+    #[cfg(not(feature = "psram"))]
+    {
+        unsafe { alloc::alloc::dealloc(ptr, layout.into()) }
+    }
+}
+
+const _: Print = print;
+pub extern "C" fn print(ptr: *const u8, len: usize) {
+    // SAFETY: caller guarantees `ptr` is valid for `len` bytes
+    let slice = unsafe { core::slice::from_raw_parts(ptr, len) };
+
+    if let Ok(_msg) = core::str::from_utf8(slice) {
+        #[cfg(feature = "defmt")]
+        defmt::info!("print: {}", _msg);
+    } else {
+        #[cfg(feature = "defmt")]
+        defmt::warn!("print: <invalid utf8>");
+    }
+}
+
+const _: SleepMs = sleep;
+pub extern "C" fn sleep(ms: u64) {
+    let cycles_per_ms = clk_sys_freq() / 1000;
+    let total_cycles = ms * cycles_per_ms as u64;
+
+    for _ in 0..total_cycles {
+        cortex_m::asm::nop();
+    }
+}
+
+pub static mut MS_SINCE_LAUNCH: Option<Instant> = None;
+
+const _: GetMs = get_ms;
+pub extern "C" fn get_ms() -> u64 {
+    Instant::now()
+        .duration_since(unsafe { MS_SINCE_LAUNCH.unwrap() })
+        .as_millis()
+}
+
+const _: DrawIter = draw_iter;
+pub extern "C" fn draw_iter(cpixels: *const CPixel, len: usize) {
+    // SAFETY: caller guarantees `ptr` is valid for `len` bytes
+    let cpixels = unsafe { core::slice::from_raw_parts(cpixels, len) };
+
+    let iter = cpixels.iter().copied().map(|c: CPixel| c.into());
+
+    FB_PAUSED.store(true, Ordering::Release);
+    unsafe { FRAMEBUFFER.as_mut().unwrap().draw_iter(iter).unwrap() }
+    FB_PAUSED.store(false, Ordering::Release);
+}
+
+pub static mut KEY_CACHE: Queue<KeyEvent, 32> = Queue::new();
+
+const _: GetKey = get_key;
+pub extern "C" fn get_key() -> KeyEventC {
+    if let Some(event) = unsafe { KEY_CACHE.dequeue() } {
+        event.into()
+    } else {
+        KeyEvent {
+            key: KeyCode::Unknown(0),
+            state: KeyState::Idle,
+            mods: Modifiers::empty(),
+        }
+        .into()
+    }
+}
+
+const _: GenRand = gen_rand;
+pub extern "C" fn gen_rand(req: &mut RngRequest) {
+    let mut rng = RoscRng;
+
+    match req {
+        RngRequest::U32(i) => *i = rng.next_u32(),
+        RngRequest::U64(i) => *i = rng.next_u64(),
+        RngRequest::Bytes { ptr, len } => {
+            // SAFETY: caller guarantees `ptr` is valid for `len` bytes
+            let slice: &mut [u8] = unsafe { core::slice::from_raw_parts_mut(*ptr, *len) };
+            rng.fill_bytes(slice);
+        }
+    }
+}
+
+unsafe fn copy_entry_to_user_buf(name: &[u8], dest: *mut c_char, max_str_len: usize) {
+    if !dest.is_null() {
+        let len = name.len().min(max_str_len - 1);
+        unsafe {
+            ptr::copy_nonoverlapping(name.as_ptr(), dest, len);
+            *dest.add(len) = 0; // nul terminator
+        }
+    }
+}
+
+unsafe fn get_dir_entries(dir: &Dir, entries: &mut [*mut c_char], max_str_len: usize) -> usize {
+    let mut b = [0; 25];
+    let mut buf = LfnBuffer::new(&mut b);
+    let mut i = 0;
+    dir.iterate_dir_lfn(&mut buf, |entry, lfn_name| {
+        if i < entries.len() {
+            if let Some(name) = lfn_name {
+                unsafe { copy_entry_to_user_buf(name.as_bytes(), entries[i], max_str_len) };
+            } else {
+                unsafe { copy_entry_to_user_buf(entry.name.base_name(), entries[i], max_str_len) };
+            }
+            i += 1;
+        }
+    })
+    .unwrap();
+    i
+}
+
+unsafe fn recurse_dir(
+    dir: &Dir,
+    dirs: &[&str],
+    entries: &mut [*mut c_char],
+    max_str_len: usize,
+) -> usize {
+    if dirs.is_empty() {
+        return unsafe { get_dir_entries(dir, entries, max_str_len) };
+    }
+
+    let dir = dir.open_dir(dirs[0]).unwrap();
+    unsafe { recurse_dir(&dir, &dirs[1..], entries, max_str_len) }
+}
+
+const _: ListDir = list_dir;
+pub extern "C" fn list_dir(
+    dir: *const u8,
+    len: usize,
+    entries: *mut *mut c_char,
+    files_len: usize,
+    max_entry_str_len: usize,
+) -> usize {
+    // SAFETY: caller guarantees `ptr` is valid for `len` bytes
+    let files = unsafe { core::slice::from_raw_parts_mut(entries, files_len) };
+    // SAFETY: caller guarantees `ptr` is valid for `len` bytes
+    let dir = unsafe { core::str::from_raw_parts(dir, len) };
+    let dirs: Vec<&str> = dir.split('/').collect();
+
+    let mut guard = SDCARD.get().try_lock().expect("Failed to get sdcard");
+    let sd = guard.as_mut().unwrap();
+
+    let mut wrote = 0;
+    sd.access_root_dir(|root| {
+        if dirs[0].is_empty() && dirs.len() >= 2 {
+            unsafe {
+                if dir == "/" {
+                    wrote = get_dir_entries(&root, files, max_entry_str_len);
+                } else {
+                    wrote = recurse_dir(&root, &dirs[1..], files, max_entry_str_len);
+                }
+            }
+        }
+    });
+    wrote
+}
+
+fn recurse_file<T>(
+    dir: &Dir,
+    dirs: &[&str],
+    mut access: impl FnMut(&mut File) -> T,
+) -> Result<T, ()> {
+    if dirs.len() == 1 {
+        let mut b = [0_u8; 50];
+        let mut buf = LfnBuffer::new(&mut b);
+        let mut short_name = None;
+        dir.iterate_dir_lfn(&mut buf, |entry, name| {
+            if let Some(name) = name
+                && (name == dirs[0] || entry.name.to_string().as_str() == dirs[0])
+            {
+                short_name = Some(entry.name.clone());
+            }
+        })
+        .expect("Failed to iterate dir");
+
+        if let Some(name) = short_name {
+            let mut file = dir
+                .open_file_in_dir(name, embedded_sdmmc::Mode::ReadWriteAppend)
+                .map_err(|_| ())?;
+            return Ok(access(&mut file));
+        }
+        return Err(());
+    }
+
+    let dir = dir.open_dir(dirs[0]).unwrap();
+    recurse_file(&dir, &dirs[1..], access)
+}
+
+const _: ReadFile = read_file;
+pub extern "C" fn read_file(
+    str: *const u8,
+    len: usize,
+    start_from: usize,
+    buf: *mut u8,
+    buf_len: usize,
+) -> usize {
+    // SAFETY: caller guarantees `ptr` is valid for `len` bytes
+    let file = unsafe { core::str::from_raw_parts(str, len) };
+
+    let mut components: [&str; 8] = [""; 8];
+    let mut count = 0;
+    for part in file.split('/') {
+        if count >= components.len() {
+            break;
+        }
+        components[count] = part;
+        count += 1;
+    }
+
+    // SAFETY: caller guarantees `ptr` is valid for `len` bytes
+    let buf = unsafe { core::slice::from_raw_parts_mut(buf, buf_len) };
+
+    let mut read = 0;
+
+    let mut guard = SDCARD.get().try_lock().expect("Failed to get sdcard");
+    let sd = guard.as_mut().unwrap();
+    if !file.is_empty() {
+        sd.access_root_dir(|root| {
+            if let Ok(result) = recurse_file(&root, &components[1..count], |file| {
+                file.seek_from_start(start_from as u32).unwrap_or(());
+                file.read(buf).unwrap()
+            }) {
+                read = result
+            };
+        });
+    }
+    read
+}
+
+const _: WriteFile = write_file;
+pub extern "C" fn write_file(
+    str: *const u8,
+    len: usize,
+    start_from: usize,
+    buf: *const u8,
+    buf_len: usize,
+) {
+    // SAFETY: caller guarantees str ptr is valid for `len` bytes
+    let file = unsafe { core::str::from_raw_parts(str, len) };
+
+    let mut components: [&str; 8] = [""; 8];
+    let mut count = 0;
+    for part in file.split('/') {
+        if count >= components.len() {
+            break;
+        }
+        components[count] = part;
+        count += 1;
+    }
+
+    // SAFETY: caller guarantees buf ptr is valid for `buf_len` bytes
+    let buf = unsafe { core::slice::from_raw_parts(buf, buf_len) };
+
+    let mut guard = SDCARD.get().try_lock().expect("Failed to get sdcard");
+    let sd = guard.as_mut().unwrap();
+    if !file.is_empty() {
+        sd.access_root_dir(|root| {
+            recurse_file(&root, &components[1..count], |file| {
+                file.seek_from_start(start_from as u32).unwrap();
+                file.write(buf).unwrap()
+            })
+            .unwrap_or(())
+        });
+    };
+}
+
+const _: FileLen = file_len;
+pub extern "C" fn file_len(str: *const u8, len: usize) -> usize {
+    // SAFETY: caller guarantees str ptr is valid for `len` bytes
+    let file = unsafe { core::str::from_raw_parts(str, len) };
+    let file: Vec<&str> = file.split('/').collect();
+
+    let mut len = 0;
+
+    let mut guard = SDCARD.get().try_lock().expect("Failed to get sdcard");
+    let sd = guard.as_mut().unwrap();
+    if !file.is_empty() {
+        sd.access_root_dir(|root| {
+            if let Ok(result) = recurse_file(&root, &file[1..], |file| file.length()) {
+                len = result
+            }
+        });
+    }
+    len as usize
+}
+
+const _: AudioBufferReady = audio_buffer_ready;
+pub extern "C" fn audio_buffer_ready() -> bool {
+    AUDIO_BUFFER_READY.load(Ordering::Acquire)
+}
+
+const _: SendAudioBuffer = send_audio_buffer;
+pub extern "C" fn send_audio_buffer(ptr: *const u8, len: usize) {
+    // SAFETY: caller guarantees `ptr` is valid for `len` bytes
+    let buf = unsafe { core::slice::from_raw_parts(ptr, len) };
+
+    while !AUDIO_BUFFER_READY.load(Ordering::Acquire) {
+        core::hint::spin_loop();
+    }
+
+    if buf.len() == AUDIO_BUFFER_SAMPLES * 2 {
+        AUDIO_BUFFER_READY.store(false, Ordering::Release);
+        unsafe { AUDIO_BUFFER.copy_from_slice(buf) };
+        AUDIO_BUFFER_WRITTEN.store(true, Ordering::Release);
+    } else {
+        #[cfg(feature = "defmt")]
+        defmt::warn!(
+            "user audio stream was wrong size: {} should be {}",
+            buf.len(),
+            AUDIO_BUFFER_SAMPLES * 2
+        )
+    }
+}

kernel/src/ui.rs

@@ -1,85 +1,90 @@
 use crate::{
-    BINARY_CH, TASK_STATE, TaskState,
+    BINARY_CH, display::FRAMEBUFFER, elf::load_binary, framebuffer::FB_PAUSED,
-    display::{FRAMEBUFFER, SCREEN_HEIGHT, SCREEN_WIDTH},
+    peripherals::keyboard, storage::FileName,
-    elf::load_binary,
-    format,
-    peripherals::keyboard,
-    storage::FileName,
-};
-use alloc::{string::String, vec::Vec};
-use core::{fmt::Debug, str::FromStr, sync::atomic::Ordering};
-use embassy_sync::{
-    blocking_mutex::raw::{CriticalSectionRawMutex, ThreadModeRawMutex},
-    mutex::Mutex,
 };
+use alloc::{str::FromStr, string::String, vec::Vec};
+use core::sync::atomic::Ordering;
+use embassy_sync::{blocking_mutex::raw::CriticalSectionRawMutex, mutex::Mutex};
 use embedded_graphics::{
     Drawable,
-    mono_font::{MonoTextStyle, ascii::FONT_9X15},
+    mono_font::{MonoTextStyle, ascii::FONT_10X20},
     pixelcolor::Rgb565,
-    prelude::{Dimensions, Point, RgbColor, Size},
+    prelude::{Dimensions, Point, Primitive, RgbColor, Size},
-    primitives::Rectangle,
+    primitives::{PrimitiveStyle, Rectangle},
     text::Text,
 };
 use embedded_layout::{
     align::{horizontal, vertical},
-    layout::linear::LinearLayout,
+    layout::linear::{FixedMargin, LinearLayout},
-    object_chain::Chain,
     prelude::*,
 };
 use embedded_text::TextBox;
-use shared::keyboard::{KeyCode, KeyState};
+use userlib_sys::keyboard::{KeyCode, KeyState};
 
 pub static SELECTIONS: Mutex<CriticalSectionRawMutex, SelectionList> =
     Mutex::new(SelectionList::new());
 
 pub async fn ui_handler() {
     loop {
-        if let TaskState::Ui = *TASK_STATE.lock().await {
+        if let Some(event) = keyboard::read_keyboard_fifo().await
-            if let Some(event) = keyboard::read_keyboard_fifo().await {
+            && let KeyState::Pressed = event.state
-                if let KeyState::Pressed = event.state {
+        {
-                    match event.key {
+            match event.key {
-                        KeyCode::JoyUp => {
+                KeyCode::Up => {
-                            let mut selections = SELECTIONS.lock().await;
+                    let mut selections = SELECTIONS.lock().await;
-                            selections.up();
+                    selections.up();
-                        }
-                        KeyCode::JoyDown => {
-                            let mut selections = SELECTIONS.lock().await;
-                            selections.down();
-                        }
-                        KeyCode::Enter | KeyCode::JoyRight => {
-                            let selections = SELECTIONS.lock().await;
-                            let selection = selections.selections
-                                [selections.current_selection as usize - 1]
-                                .clone();
-
-                            let entry =
-                                unsafe { load_binary(&selection.short_name).await.unwrap() };
-                            BINARY_CH.send(entry).await;
-                        }
-                        _ => (),
-                    }
                 }
-            }
+                KeyCode::Down => {
+                    let mut selections = SELECTIONS.lock().await;
+                    selections.down();
+                }
+                KeyCode::Enter | KeyCode::Right => {
+                    let selections = SELECTIONS.lock().await;
+                    let selection =
+                        selections.selections[selections.current_selection as usize].clone();
 
+                    let entry = unsafe {
+                        load_binary(&selection.short_name)
+                            .await
+                            .expect("unable to load binary")
+                    };
+                    BINARY_CH.send(entry).await;
+                }
+                _ => (),
+            }
+        }
+
+        let changed = SELECTIONS.lock().await.changed;
+        if changed {
+            clear_selection().await;
             draw_selection().await;
-        } else {
-            embassy_time::Timer::after_millis(50).await;
         }
     }
 }
 
-async fn draw_selection() {
+pub async fn clear_selection() {
-    let file_names: Vec<FileName> = {
+    let sel = SELECTIONS.lock().await;
-        let guard = SELECTIONS.lock().await;
-        guard.selections.clone()
-    };
 
-    let text_style = MonoTextStyle::new(&FONT_9X15, Rgb565::WHITE);
+    if let Some(area) = sel.last_bounds {
-    let display_area = unsafe { FRAMEBUFFER.bounding_box() };
+        Rectangle::new(area.top_left, area.size)
+            .into_styled(PrimitiveStyle::with_fill(Rgb565::BLACK))
+            .draw(unsafe { &mut *FRAMEBUFFER.as_mut().unwrap() })
+            .unwrap();
+    }
+}
+
+async fn draw_selection() {
+    let mut guard = SELECTIONS.lock().await;
+    let file_names = guard.selections.clone();
+
+    let text_style = MonoTextStyle::new(&FONT_10X20, Rgb565::WHITE);
+    let display_area = unsafe { FRAMEBUFFER.as_mut().unwrap().bounding_box() };
 
     const NO_BINS: &str = "No Programs found on SD Card. Ensure programs end with '.bin', and are located in the root directory";
     let no_bins = String::from_str(NO_BINS).unwrap();
 
+    FB_PAUSED.store(true, Ordering::Release); // ensure all elements show up at once
+
     if file_names.is_empty() {
         TextBox::new(
             &no_bins,
@@ -89,64 +94,94 @@ async fn draw_selection() {
             ),
             text_style,
         )
-        .draw(unsafe { &mut FRAMEBUFFER })
+        .draw(unsafe { &mut *FRAMEBUFFER.as_mut().unwrap() })
         .unwrap();
     } else {
-        let mut file_names = file_names.iter();
+        let mut views: alloc::vec::Vec<Text<MonoTextStyle<Rgb565>>> = Vec::new();
-        let Some(first) = file_names.next() else {
-            Text::new(NO_BINS, Point::zero(), text_style)
-                .draw(unsafe { &mut FRAMEBUFFER })
-                .unwrap();
 
-            return;
+        for i in &file_names {
-        };
+            views.push(Text::new(&i.long_name, Point::zero(), text_style));
+        }
 
-        let chain = Chain::new(Text::new(&first.long_name, Point::zero(), text_style));
+        let views_group = Views::new(views.as_mut_slice());
 
-        // for _ in 0..file_names.len() {
+        let layout = LinearLayout::vertical(views_group)
-        //     let chain = chain.append(Text::new(
-        //         file_names.next().unwrap(),
-        //         Point::zero(),
-        //         text_style,
-        //     ));
-        // }
-
-        LinearLayout::vertical(chain)
             .with_alignment(horizontal::Center)
+            .with_spacing(FixedMargin(5))
             .arrange()
-            .align_to(&display_area, horizontal::Center, vertical::Center)
+            .align_to(&display_area, horizontal::Center, vertical::Center);
-            .draw(unsafe { &mut FRAMEBUFFER })
+
+        // draw selected box
+        let selected_bounds = layout
+            .inner()
+            .get(guard.current_selection as usize)
+            .expect("Selected binary missing")
+            .bounding_box();
+        Rectangle::new(selected_bounds.top_left, selected_bounds.size)
+            .into_styled(PrimitiveStyle::with_stroke(Rgb565::WHITE, 1))
+            .draw(unsafe { &mut *FRAMEBUFFER.as_mut().unwrap() })
+            .unwrap();
+
+        guard.last_bounds = Some(layout.bounds());
+
+        layout
+            .draw(unsafe { &mut *FRAMEBUFFER.as_mut().unwrap() })
             .unwrap();
     }
+
+    guard.changed = false;
+    FB_PAUSED.store(false, Ordering::Release); // ensure all elements show up at once
 }
 
 #[derive(Clone)]
 pub struct SelectionList {
+    // allows easy clearing of selection ui,
+    // based on previous bounds
+    last_bounds: Option<Rectangle>,
     current_selection: u16,
-    pub selections: Vec<FileName>,
+    selections: Vec<FileName>,
+    changed: bool,
 }
 
 impl SelectionList {
     pub const fn new() -> Self {
         Self {
+            last_bounds: None,
             selections: Vec::new(),
             current_selection: 0,
+            changed: false,
         }
     }
 
+    pub fn set_changed(&mut self, changed: bool) {
+        self.changed = changed
+    }
+
+    pub fn update_selections(&mut self, selections: Vec<FileName>) {
+        self.selections = selections;
+        self.changed = true;
+    }
+
+    pub fn selections(&self) -> &Vec<FileName> {
+        &self.selections
+    }
+
     pub fn reset(&mut self) {
-        self.current_selection = 1
+        self.current_selection = 0;
+        self.changed = true;
+    }
+
+    fn up(&mut self) {
+        if self.current_selection > 0 {
+            self.current_selection -= 1;
+            self.changed = true;
+        }
     }
 
     fn down(&mut self) {
         if self.current_selection + 1 < self.selections.len() as u16 {
-            self.current_selection += 1
+            self.current_selection += 1;
-        }
+            self.changed = true;
-    }
-
-    fn up(&mut self) {
-        if self.current_selection > self.selections.len() as u16 {
-            self.current_selection -= 1
         }
     }
 }

kernel/src/usb.rs

@@ -1,11 +1,12 @@
-use crate::{TASK_STATE, TASK_STATE_CHANGED, TaskState, scsi::MassStorageClass};
+use crate::{scsi::MassStorageClass, storage::SdCard};
-use embassy_futures::{
+use core::sync::atomic::{AtomicBool, Ordering};
-    join::join,
+use embassy_futures::select::select;
-    select::{select, select3},
-};
 use embassy_rp::{peripherals::USB, usb::Driver};
-use embassy_usb::{Builder, Config};
+use embassy_usb::{Builder, Config, UsbDevice};
 
+pub static USB_ACTIVE: AtomicBool = AtomicBool::new(false);
+
+#[embassy_executor::task]
 pub async fn usb_handler(driver: Driver<'static, USB>) {
     let mut config = Config::new(0xc0de, 0xbabe);
     config.manufacturer = Some("LegitCamper");
@@ -27,17 +28,18 @@ pub async fn usb_handler(driver: Driver<'static, USB>) {
         &mut control_buf,
     );
 
-    let mut scsi = MassStorageClass::new(&mut builder);
+    let temp_sd: Option<SdCard> = None;
-    let mut usb = builder.build();
+    let mut scsi = MassStorageClass::new(&mut builder, temp_sd);
+    let usb = builder.build();
 
+    select(run(usb), scsi.poll()).await;
+}
+
+async fn run<'d>(mut usb: UsbDevice<'d, Driver<'d, USB>>) -> ! {
     loop {
-        defmt::info!("in: {}", *TASK_STATE.lock().await as u32);
+        usb.wait_resume().await;
-        if *TASK_STATE.lock().await == TaskState::Ui {
+        USB_ACTIVE.store(true, Ordering::Release);
-            defmt::info!("running scsi and usb");
+        usb.run_until_suspend().await;
-            select(join(usb.run(), scsi.poll()), TASK_STATE_CHANGED.wait()).await;
+        USB_ACTIVE.store(false, Ordering::Release);
-        } else {
-            defmt::info!("not in ui state");
-            TASK_STATE_CHANGED.wait().await;
-        }
     }
 }

selection_ui/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "selection_ui"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+userlib = { path = "../userlib" }
+embedded-graphics = "0.8.1"
+embedded-layout = "0.4.2"
+embedded-text = "0.7.3"

selection_ui/src/lib.rs

@@ -0,0 +1,153 @@
+#![no_std]
+
+extern crate alloc;
+
+use alloc::vec::Vec;
+use embedded_graphics::{
+    mono_font::{ascii::FONT_10X20, MonoTextStyle},
+    pixelcolor::Rgb565,
+    prelude::{Dimensions, DrawTarget, Point, Primitive, RgbColor},
+    primitives::{PrimitiveStyle, Rectangle},
+    text::{renderer::TextRenderer, Alignment, Text},
+    Drawable,
+};
+use embedded_layout::{
+    align::{horizontal, vertical},
+    layout::linear::{FixedMargin, LinearLayout},
+    prelude::*,
+};
+use userlib::{
+    display::Display,
+    get_key,
+    keyboard::{KeyCode, KeyState},
+};
+
+#[derive(Debug)]
+pub enum SelectionUiError<DisplayError> {
+    SelectionListEmpty,
+    DisplayError(DisplayError),
+}
+
+pub struct SelectionUi<'a> {
+    selection: usize,
+    items: &'a [&'a str],
+    last_bounds: Option<Rectangle>,
+}
+
+impl<'a> SelectionUi<'a> {
+    pub fn new(items: &'a [&'a str]) -> Self {
+        Self {
+            selection: 0,
+            items,
+            last_bounds: None,
+        }
+    }
+
+    pub fn run_selection_ui(
+        &mut self,
+        display: &mut Display,
+    ) -> Result<Option<usize>, SelectionUiError<<Display as DrawTarget>::Error>> {
+        self.draw(display)?;
+        let selection;
+        loop {
+            let key = get_key();
+            if key.state == KeyState::Pressed
+                && let Some(s) = self.update(display, key.key)? {
+                    selection = Some(s);
+                    display
+                        .clear(Rgb565::BLACK)
+                        .map_err(SelectionUiError::DisplayError)?;
+                    break;
+                }
+        }
+        Ok(selection)
+    }
+
+    /// updates the display with a new keypress.
+    /// returns selection idx if selected
+    pub fn update(
+        &mut self,
+        display: &mut Display,
+        key: KeyCode,
+    ) -> Result<Option<usize>, SelectionUiError<<Display as DrawTarget>::Error>> {
+        match key {
+            KeyCode::Down => {
+                self.selection = (self.selection + 1).min(self.items.len() - 1);
+            }
+            KeyCode::Up => {
+                self.selection = self.selection.saturating_sub(1);
+            }
+            KeyCode::Enter | KeyCode::Right => return Ok(Some(self.selection)),
+            _ => return Ok(None),
+        };
+        self.draw(display)?;
+        Ok(None)
+    }
+
+    fn draw(
+        &mut self,
+        display: &mut Display,
+    ) -> Result<(), SelectionUiError<<Display as DrawTarget>::Error>> {
+        let text_style = MonoTextStyle::new(&FONT_10X20, Rgb565::WHITE);
+        let display_area = display.bounding_box();
+
+        if self.items.is_empty() {
+            return Err(SelectionUiError::SelectionListEmpty);
+        }
+
+        if let Some(bounds) = self.last_bounds {
+            Rectangle::new(bounds.top_left, bounds.size)
+                .into_styled(PrimitiveStyle::with_fill(Rgb565::BLACK))
+                .draw(display)
+                .map_err(SelectionUiError::DisplayError)?;
+        }
+
+        let mut views: Vec<Text<MonoTextStyle<Rgb565>>> = Vec::new();
+
+        for i in self.items {
+            views.push(Text::new(i, Point::zero(), text_style));
+        }
+
+        let views_group = Views::new(views.as_mut_slice());
+
+        let layout = LinearLayout::vertical(views_group)
+            .with_alignment(horizontal::Center)
+            .with_spacing(FixedMargin(5))
+            .arrange()
+            .align_to(&display_area, horizontal::Center, vertical::Center);
+
+        layout
+            .draw(display)
+            .map_err(SelectionUiError::DisplayError)?;
+
+        // draw selected box
+        if let Some(selected_bounds) = layout.inner().get(self.selection) {
+            let selected_bounds = selected_bounds.bounding_box();
+            Rectangle::new(selected_bounds.top_left, selected_bounds.size)
+                .into_styled(PrimitiveStyle::with_stroke(Rgb565::WHITE, 1))
+                .draw(display)
+                .map_err(SelectionUiError::DisplayError)?;
+
+            self.last_bounds = Some(selected_bounds);
+        }
+
+        Ok(())
+    }
+}
+
+pub fn draw_text_center<S>(
+    display: &mut Display,
+    text: &str,
+    style: S,
+) -> Result<Point, <Display as DrawTarget>::Error>
+where
+    S: TextRenderer<Color = <Display as DrawTarget>::Color>,
+{
+    Text::with_alignment(
+        text,
+        display.bounding_box().center(),
+        style,
+        Alignment::Center,
+    )
+    .draw(display)
+}

shared/Cargo.toml

@@ -1,11 +0,0 @@
-[package]
-name = "shared"
-version = "0.1.0"
-edition = "2024"
-
-[features]
-defmt = ["dep:defmt"]
-
-[dependencies]
-bitflags = "2.9.1"
-defmt = { version = "1.0.1", optional = true }

shared/src/lib.rs

@@ -1,142 +0,0 @@
-#![no_std]
-
-pub mod keyboard {
-    bitflags::bitflags! {
-        #[derive(Default, Debug, PartialEq, Eq, Clone, Copy)]
-        pub struct Modifiers: u8 {
-            const NONE = 0;
-            const CTRL = 1;
-            const ALT = 2;
-            const LSHIFT = 4;
-            const RSHIFT = 8;
-            const SYM = 16;
-        }
-    }
-
-    #[derive(Debug)]
-    pub struct KeyEvent {
-        pub key: KeyCode,
-        pub state: KeyState,
-        pub mods: Modifiers,
-    }
-
-    #[cfg_attr(feature = "defmt", derive(defmt::Format))]
-    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-    pub enum KeyState {
-        Idle = 0,
-        Pressed = 1,
-        Hold = 2,
-        Released = 3,
-    }
-
-    impl From<u8> for KeyState {
-        fn from(value: u8) -> Self {
-            match value {
-                1 => KeyState::Pressed,
-                2 => KeyState::Hold,
-                3 => KeyState::Released,
-                0 | _ => KeyState::Idle,
-            }
-        }
-    }
-
-    #[cfg_attr(feature = "defmt", derive(defmt::Format))]
-    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-    #[repr(C)]
-    #[repr(u8)]
-    pub enum KeyCode {
-        JoyUp = 0x01,
-        JoyDown = 0x02,
-        JoyLeft = 0x03,
-        JoyRight = 0x04,
-        JoyCenter = 0x05,
-        BtnLeft1 = 0x06,
-        BtnRight1 = 0x07,
-        BtnLeft2 = 0x11,
-        BtnRight2 = 0x12,
-        Backspace = 0x08,
-        Tab = 0x09,
-        Enter = 0x0A,
-        ModAlt = 0xA1,
-        ModShiftLeft = 0xA2,
-        ModShiftRight = 0xA3,
-        ModSym = 0xA4,
-        ModCtrl = 0xA5,
-        Esc = 0xB1,
-        Left = 0xB4,
-        Up = 0xB5,
-        Down = 0xB6,
-        Right = 0xB7,
-        Break = 0xD0,
-        Insert = 0xD1,
-        Home = 0xD2,
-        Del = 0xD4,
-        End = 0xD5,
-        PageUp = 0xD6,
-        PageDown = 0xD7,
-        CapsLock = 0xC1,
-        F1 = 0x81,
-        F2 = 0x82,
-        F3 = 0x83,
-        F4 = 0x84,
-        F5 = 0x85,
-        F6 = 0x86,
-        F7 = 0x87,
-        F8 = 0x88,
-        F9 = 0x89,
-        F10 = 0x90,
-        Char(char),
-        Unknown(u8),
-    }
-
-    impl From<u8> for KeyCode {
-        fn from(value: u8) -> Self {
-            match value {
-                0x01 => Self::JoyUp,
-                0x02 => Self::JoyDown,
-                0x03 => Self::JoyLeft,
-                0x04 => Self::JoyRight,
-                0x05 => Self::JoyCenter,
-                0x06 => Self::BtnLeft1,
-                0x07 => Self::BtnRight1,
-                0x08 => Self::Backspace,
-                0x09 => Self::Tab,
-                0x0A => Self::Enter,
-                0x11 => Self::BtnLeft2,
-                0x12 => Self::BtnRight2,
-                0xA1 => Self::ModAlt,
-                0xA2 => Self::ModShiftLeft,
-                0xA3 => Self::ModShiftRight,
-                0xA4 => Self::ModSym,
-                0xA5 => Self::ModCtrl,
-                0xB1 => Self::Esc,
-                0xB4 => Self::Left,
-                0xB5 => Self::Up,
-                0xB6 => Self::Down,
-                0xB7 => Self::Right,
-                0xC1 => Self::CapsLock,
-                0xD0 => Self::Break,
-                0xD1 => Self::Insert,
-                0xD2 => Self::Home,
-                0xD4 => Self::Del,
-                0xD5 => Self::End,
-                0xD6 => Self::PageUp,
-                0xD7 => Self::PageDown,
-                0x81 => Self::F1,
-                0x82 => Self::F2,
-                0x83 => Self::F3,
-                0x84 => Self::F4,
-                0x85 => Self::F5,
-                0x86 => Self::F6,
-                0x87 => Self::F7,
-                0x88 => Self::F8,
-                0x89 => Self::F9,
-                0x90 => Self::F10,
-                _ => match char::from_u32(value as u32) {
-                    Some(c) => Self::Char(c),
-                    None => Self::Unknown(value),
-                },
-            }
-        }
-    }
-}

user-apps/calculator/src/main.rs

@@ -1,77 +0,0 @@
-#![no_std]
-#![no_main]
-
-extern crate alloc;
-use abi::{KeyCode, display::Display, embassy_time, get_key, print, sleep};
-use alloc::{boxed::Box, string::String, vec};
-use core::{panic::PanicInfo, pin::Pin};
-use embedded_graphics::{
-    Drawable,
-    geometry::{Dimensions, Point},
-    mono_font::{MonoTextStyle, ascii::FONT_6X10},
-    pixelcolor::Rgb565,
-    prelude::{Primitive, RgbColor, Size},
-    primitives::{PrimitiveStyle, Rectangle},
-    text::{Alignment, Text},
-};
-
-#[panic_handler]
-fn panic(_info: &PanicInfo) -> ! {
-    loop {}
-}
-
-pub async fn main() {
-    print("Starting Async Calculator app");
-    let mut display = Display;
-
-    let character_style = MonoTextStyle::new(&FONT_6X10, Rgb565::RED);
-
-    let mut text = vec!['T', 'y', 'p', 'e'];
-    let mut dirty = true;
-    let mut last_bounds: Option<Rectangle> = None;
-
-    loop {
-        if dirty {
-            if let Some(bounds) = last_bounds {
-                Rectangle::new(bounds.top_left, bounds.size)
-                    .into_styled(PrimitiveStyle::with_fill(Rgb565::BLACK))
-                    .draw(&mut display)
-                    .unwrap();
-            }
-
-            let text = text.iter().cloned().collect::<String>();
-            let aligned_text = Text::with_alignment(
-                &text,
-                display.bounding_box().center(),
-                character_style,
-                Alignment::Center,
-            );
-            last_bounds = Some(aligned_text.bounding_box());
-
-            aligned_text.draw(&mut display).unwrap();
-            dirty = false;
-        }
-
-        if let Some(event) = get_key() {
-            dirty = true;
-            match event.key {
-                KeyCode::Char(ch) => {
-                    text.push(ch);
-                }
-                KeyCode::Del => {
-                    text.clear();
-                }
-                KeyCode::Backspace => {
-                    text.pop();
-                }
-                KeyCode::Esc => return,
-                _ => (),
-            }
-        }
-    }
-}
-
-#[unsafe(no_mangle)]
-pub extern "Rust" fn _start() -> Pin<Box<dyn Future<Output = ()>>> {
-    Box::pin(async { main().await })
-}

user_apps/calculator/Cargo.toml

@@ -4,5 +4,6 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-abi = { path = "../../abi" }
+userlib = { path = "../../userlib" }
 embedded-graphics = "0.8.1"
+embedded-layout = "0.4.2"

user_apps/calculator/src/main.rs

@@ -0,0 +1,200 @@
+#![no_std]
+#![no_main]
+
+extern crate alloc;
+use alloc::{format, string::String, vec, vec::Vec};
+use core::panic::PanicInfo;
+use embedded_graphics::{
+    Drawable,
+    geometry::{Dimensions, Point},
+    mono_font::{MonoTextStyle, ascii::FONT_7X14, iso_8859_1::FONT_10X20},
+    pixelcolor::Rgb565,
+    prelude::{Primitive, RgbColor},
+    primitives::{PrimitiveStyle, Rectangle},
+    text::Text,
+};
+use embedded_layout::{
+    View,
+    align::{Align, horizontal, vertical},
+    layout::linear::LinearLayout,
+    prelude::Chain,
+};
+use userlib::{
+    display::Display,
+    get_key,
+    keyboard::{KeyCode, KeyState},
+    println,
+};
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    println!("user panic: {} @ {:?}", info.message(), info.location(),);
+    loop {}
+}
+
+#[unsafe(no_mangle)]
+pub extern "Rust" fn _start() {
+    main()
+}
+
+pub fn main() {
+    println!("Starting Calculator app");
+    let mut display = Display::take().unwrap();
+
+    let mut input = vec!['e', 'x', 'p', 'r', ':', ' '];
+    let input_min = input.len();
+    let mut dirty = true;
+    let mut last_area: Option<(Rectangle, Rectangle)> = None;
+
+    LinearLayout::vertical(Chain::new(Text::new(
+        "Calculator!",
+        Point::zero(),
+        MonoTextStyle::new(&FONT_10X20, Rgb565::WHITE),
+    )))
+    .arrange()
+    .align_to(&display.bounding_box(), horizontal::Center, vertical::Top)
+    .draw(&mut display)
+    .expect("Failed to draw title");
+
+    loop {
+        if dirty {
+            let style = PrimitiveStyle::with_fill(Rgb565::BLACK);
+            if let Some(area) = last_area {
+                Rectangle::new(area.0.top_left, area.0.size)
+                    .into_styled(style)
+                    .draw(&mut display)
+                    .unwrap();
+
+                Rectangle::new(area.1.top_left, area.1.size)
+                    .into_styled(style)
+                    .draw(&mut display)
+                    .unwrap();
+            }
+
+            let text = input.iter().cloned().collect::<String>();
+
+            let style = MonoTextStyle::new(&FONT_7X14, Rgb565::WHITE);
+            let expr_layout = LinearLayout::vertical(Chain::new(Text::new(
+                &text,
+                display.bounding_box().center(),
+                style,
+            )))
+            .arrange()
+            .align_to(&display.bounding_box(), horizontal::Left, vertical::Center);
+
+            let result = if let Ok(result) = evaluate(&input[input_min..]) {
+                &format!(" = {result}")
+            } else {
+                " = Error"
+            };
+
+            let eq_layout = LinearLayout::vertical(Chain::new(Text::new(
+                result,
+                display.bounding_box().center(),
+                style,
+            )))
+            .arrange()
+            .align_to(&display.bounding_box(), horizontal::Right, vertical::Center);
+
+            last_area = Some((expr_layout.bounds(), eq_layout.bounds()));
+            expr_layout.draw(&mut display).unwrap();
+            eq_layout.draw(&mut display).unwrap();
+
+            dirty = false;
+        }
+
+        let event = get_key();
+        if event.state == KeyState::Released {
+            match event.key {
+                KeyCode::Char(ch) => {
+                    input.push(ch);
+                }
+                KeyCode::Del => {
+                    input.truncate(input_min);
+                }
+                KeyCode::Backspace => {
+                    if input.len() > input_min {
+                        input.pop();
+                    }
+                }
+                KeyCode::Esc => return,
+                _ => (),
+            }
+            dirty = true;
+        }
+    }
+}
+
+fn get_int(int: &[char]) -> Result<i32, ()> {
+    let mut output: i32 = 0;
+    for &c in int {
+        let digit = c.to_digit(10).ok_or(())? as i32;
+        output = output
+            .checked_mul(10)
+            .and_then(|v| v.checked_add(digit))
+            .ok_or(())?;
+    }
+    Ok(output)
+}
+
+fn primary(input: &[char], pos: &mut usize) -> Result<i32, ()> {
+    let mut digits = Vec::new();
+    while *pos < input.len() && input[*pos].is_ascii_digit() {
+        digits.push(input[*pos]);
+        *pos += 1;
+    }
+    if digits.is_empty() {
+        return Err(());
+    }
+    get_int(&digits)
+}
+
+fn mul_div(input: &[char], pos: &mut usize) -> Result<i32, ()> {
+    let mut value = primary(input, pos)?;
+    while *pos < input.len() {
+        let op = input[*pos];
+        if op != '*' && op != '/' {
+            break;
+        }
+        *pos += 1;
+        let rhs = primary(input, pos)?;
+        value = match op {
+            '*' => value.checked_mul(rhs).ok_or(())?,
+            '/' => {
+                if rhs == 0 {
+                    return Err(());
+                }
+                value.checked_div(rhs).ok_or(())?
+            }
+            _ => unreachable!(),
+        };
+    }
+    Ok(value)
+}
+
+fn add_sub(input: &[char], pos: &mut usize) -> Result<i32, ()> {
+    let mut value = mul_div(input, pos)?;
+    while *pos < input.len() {
+        let op = input[*pos];
+        if op != '+' && op != '-' {
+            break;
+        }
+        *pos += 1;
+        let rhs = mul_div(input, pos)?;
+        value = match op {
+            '+' => value.checked_add(rhs).ok_or(())?,
+            '-' => value.checked_sub(rhs).ok_or(())?,
+            _ => unreachable!(),
+        };
+    }
+    Ok(value)
+}
+
+fn evaluate(input: &[char]) -> Result<i32, ()> {
+    let mut pos = 0;
+    let result = add_sub(input, &mut pos)?;
+    if pos != input.len() {
+        return Err(());
+    }
+    Ok(result)
+}

user_apps/gallery/Cargo.toml

@@ -1,8 +1,9 @@
 [package]
-name = "abi_sys"
+name = "gallery"
 version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+userlib = { path = "../../userlib" }
 embedded-graphics = "0.8.1"
-shared = { path = "../shared" }
+tinybmp = "0.6.0"

user_apps/gallery/build.rs

@@ -0,0 +1,28 @@
+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    File::create(out.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("../memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out.display());
+
+    println!("cargo:rerun-if-changed=memory.x");
+    println!("cargo:rustc-link-arg-bins=-Tmemory.x");
+}

user_apps/gallery/src/main.rs

@@ -0,0 +1,92 @@
+#![no_std]
+#![no_main]
+#![allow(static_mut_refs)]
+
+extern crate alloc;
+use alloc::{format, vec};
+use core::panic::PanicInfo;
+use embedded_graphics::{
+    Drawable, image::Image, mono_font::MonoTextStyle, mono_font::ascii::FONT_6X10,
+    pixelcolor::Rgb565, prelude::*, text::Text,
+};
+use tinybmp::Bmp;
+use userlib::{
+    display::{Display, SCREEN_HEIGHT, SCREEN_WIDTH},
+    fs::{Entries, list_dir, read_file},
+    get_key,
+    keyboard::{KeyCode, KeyState},
+    println,
+};
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    println!("user panic: {} @ {:?}", info.message(), info.location());
+    loop {}
+}
+
+#[unsafe(no_mangle)]
+pub extern "Rust" fn _start() {
+    main()
+}
+
+pub fn main() {
+    println!("Starting Gallery app");
+    let mut bmp_buf = vec![0_u8; 100_000];
+    let mut display = Display::take().unwrap();
+
+    let grid_cols = 3;
+    let grid_rows = 3;
+    let cell_width = SCREEN_WIDTH as i32 / grid_cols;
+    let cell_height = SCREEN_HEIGHT as i32 / grid_rows;
+
+    let mut images_drawn = 0;
+
+    let mut entries = Entries::new();
+    let files_num = list_dir("/images", &mut entries);
+
+    for file in &entries.entries()[2..files_num] {
+        if images_drawn >= grid_cols * grid_rows {
+            break; // only draw 3x3
+        }
+
+        println!("file: {}", file);
+        if file.extension().unwrap_or("") == "bmp" || file.extension().unwrap_or("") == "BMP" {
+            let file_path = format!("/images/{file}");
+
+            let read = read_file(&file_path, 0, &mut bmp_buf[..]);
+            if read > 0 {
+                let bmp = Bmp::from_slice(&bmp_buf).expect("failed to parse bmp");
+
+                let row = images_drawn / grid_cols;
+                let col = images_drawn % grid_cols;
+                let cell_x = col * cell_width;
+                let cell_y = row * cell_height;
+
+                // Center image inside cell
+                let bmp_w = bmp.size().width as i32;
+                let bmp_h = bmp.size().height as i32;
+                let x = cell_x + (cell_width - bmp_w) / 2;
+                let y = cell_y + 5; // 5px top margin
+
+                Image::new(&bmp, Point::new(x, y))
+                    .draw(&mut display)
+                    .unwrap();
+
+                let text_style = MonoTextStyle::new(&FONT_6X10, Rgb565::WHITE);
+                let text_y = y + bmp_h + 2; // 2px gap under image
+                Text::new(file.base(), Point::new(cell_x + 2, text_y), text_style)
+                    .draw(&mut display)
+                    .unwrap();
+
+                images_drawn += 1;
+            }
+        }
+    }
+
+    loop {
+        let event = get_key();
+        if event.state != KeyState::Idle && event.key == KeyCode::Esc {
+            return;
+        }
+    }
+}

user_apps/gif/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "gif"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+userlib = { path = "../../userlib" }
+selection_ui = { path = "../../selection_ui" }
+embedded-graphics = "0.8.1"
+tinygif = { git = "https://github.com/LegitCamper/tinygif" }

user_apps/gif/build.rs

@@ -0,0 +1,28 @@
+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    File::create(out.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("../memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out.display());
+
+    println!("cargo:rerun-if-changed=memory.x");
+    println!("cargo:rustc-link-arg-bins=-Tmemory.x");
+}

user_apps/gif/src/main.rs

@@ -0,0 +1,98 @@
+#![no_std]
+#![no_main]
+
+extern crate alloc;
+use alloc::{format, vec, vec::Vec};
+use core::panic::PanicInfo;
+use embedded_graphics::{
+    image::ImageDrawable,
+    mono_font::{MonoTextStyle, ascii::FONT_6X10},
+    pixelcolor::Rgb565,
+    prelude::{Point, RgbColor},
+    transform::Transform,
+};
+use selection_ui::{SelectionUi, SelectionUiError, draw_text_center};
+use tinygif::Gif;
+use userlib::{
+    display::{Display, SCREEN_HEIGHT, SCREEN_WIDTH},
+    fs::{Entries, file_len, list_dir, read_file},
+    get_key, get_ms,
+    keyboard::{KeyCode, KeyState},
+    println, sleep,
+};
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    println!("user panic: {} @ {:?}", info.message(), info.location(),);
+    loop {}
+}
+
+#[unsafe(no_mangle)]
+pub extern "Rust" fn _start() {
+    main()
+}
+
+pub fn main() {
+    println!("Starting Gif app");
+    let mut display = Display::take().unwrap();
+
+    let mut entries = Entries::new();
+    list_dir("/gifs", &mut entries);
+
+    let mut files = entries.entries();
+    files.retain(|e| e.extension().unwrap_or("") == "gif");
+    let mut gifs = files.iter().map(|e| e.full_name()).collect::<Vec<&str>>();
+    gifs.sort();
+
+    let mut selection_ui = SelectionUi::new(&gifs);
+    let selection = match selection_ui.run_selection_ui(&mut display) {
+        Ok(maybe_sel) => maybe_sel,
+        Err(e) => match e {
+            SelectionUiError::SelectionListEmpty => {
+                draw_text_center(
+                    &mut display,
+                    "No Gifs were found in /gifs",
+                    MonoTextStyle::new(&FONT_6X10, Rgb565::RED),
+                )
+                .expect("Display Error");
+                None
+            }
+            SelectionUiError::DisplayError(_) => panic!("Display Error"),
+        },
+    };
+
+    assert!(selection.is_some());
+
+    let file_name = format!("/gifs/{}", gifs[selection.unwrap()]);
+    let size = file_len(&file_name);
+    let mut buf = vec![0_u8; size];
+    let read = read_file(&file_name, 0, &mut buf);
+    println!("read: {}, file size: {}", read, size);
+    assert!(read == size);
+
+    let gif = Gif::<Rgb565>::from_slice(&buf).expect("Failed to parse gif");
+
+    let translation = Point::new(
+        (SCREEN_WIDTH as i32 - gif.width() as i32) / 2,
+        (SCREEN_HEIGHT as i32 - gif.height() as i32) / 2,
+    );
+
+    let mut frame_num = 0;
+    loop {
+        for mut frame in gif.frames() {
+            let start = get_ms();
+
+            frame.translate_mut(translation).draw(&mut display).unwrap();
+            frame_num += 1;
+
+            if frame_num % 5 == 0 {
+                let event = get_key();
+                if event.state != KeyState::Idle && event.key == KeyCode::Esc {
+                    drop(buf);
+                    return;
+                };
+            }
+            sleep(((frame.delay_centis as u64) * 10).saturating_sub(start));
+        }
+    }
+}

user_apps/memory.x

@@ -1,19 +1,10 @@
 MEMORY
 {
-  /* Must match the USERAPP region in the kernel linker script */
+  RAM : ORIGIN = 0x0, LENGTH = 250K
-  RAM : ORIGIN = 0x20010000, LENGTH = 192K
 }
 
 SECTIONS
 {
-  /* Reserve first 1KB for patchable symbols */
-  .user_reloc (NOLOAD) : ALIGN(4)
-  {
-      __user_reloc_start = .;
-      KEEP(*(.user_reloc*));
-      __user_reloc_end = .;
-  } > RAM
-
   .text : ALIGN(4)
   {
       *(.text .text.*);
@@ -30,4 +21,11 @@ SECTIONS
       *(.bss .bss.*);
       *(COMMON);
   } > RAM
+
+  .syscall_table (NOLOAD) : ALIGN(4)
+  {
+      __user_reloc_start = .;
+      KEEP(*(.user_reloc*));
+      __user_reloc_end = .;
+  } > RAM
 }

user_apps/snake/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "snake"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+userlib = { path = "../../userlib" }
+embedded-graphics = "0.8.1"
+embedded-snake = { git = "https://github.com/LegitCamper/embedded-snake-rs" }
+rand = { version = "0.9.0", default-features = false }

user_apps/snake/build.rs

@@ -0,0 +1,28 @@
+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    File::create(out.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("../memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out.display());
+
+    println!("cargo:rerun-if-changed=memory.x");
+    println!("cargo:rustc-link-arg-bins=-Tmemory.x");
+}

user_apps/snake/src/main.rs

@@ -0,0 +1,65 @@
+#![no_std]
+#![no_main]
+
+extern crate alloc;
+use core::panic::PanicInfo;
+use embedded_graphics::{pixelcolor::Rgb565, prelude::RgbColor};
+use embedded_snake::{Direction, SnakeGame};
+use userlib::{
+    Rng,
+    display::{Display, SCREEN_HEIGHT, SCREEN_WIDTH},
+    get_key,
+    keyboard::{KeyCode, KeyState},
+    println, sleep,
+};
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    println!("user panic: {} @ {:?}", info.message(), info.location(),);
+    loop {}
+}
+
+#[unsafe(no_mangle)]
+pub extern "Rust" fn _start() {
+    main()
+}
+
+const CELL_SIZE: usize = 8;
+
+pub fn main() {
+    println!("Starting Snake app");
+    let mut display = Display::take().unwrap();
+
+    let mut game = SnakeGame::<100, Rgb565, Rng>::new(
+        SCREEN_WIDTH as u16,
+        SCREEN_HEIGHT as u16,
+        CELL_SIZE as u16,
+        CELL_SIZE as u16,
+        Rng,
+        Rgb565::BLACK,
+        Rgb565::GREEN,
+        Rgb565::RED,
+        50,
+    );
+
+    loop {
+        let event = get_key();
+        if event.state != KeyState::Idle {
+            let direction = match event.key {
+                KeyCode::Up => Direction::Up,
+                KeyCode::Down => Direction::Down,
+                KeyCode::Right => Direction::Right,
+                KeyCode::Left => Direction::Left,
+                KeyCode::Esc => return,
+                _ => Direction::None,
+            };
+            game.set_direction(direction);
+        };
+
+        // ensure all draws show up at once
+        game.pre_draw(&mut display);
+        game.draw(&mut display);
+
+        sleep(15);
+    }
+}

user_apps/wav_player/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "wav_player"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+userlib = { path = "../../userlib" }
+selection_ui = { path = "../../selection_ui" }
+embedded-graphics = "0.8.1"
+rand = { version = "0.9.0", default-features = false }
+embedded-audio = { git = "https://github.com/LegitCamper/embedded-audio" }

user_apps/wav_player/build.rs

@@ -0,0 +1,28 @@
+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    File::create(out.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("../memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out.display());
+
+    println!("cargo:rerun-if-changed=memory.x");
+    println!("cargo:rustc-link-arg-bins=-Tmemory.x");
+}

user_apps/wav_player/src/main.rs

@@ -0,0 +1,143 @@
+#![no_std]
+#![no_main]
+
+extern crate alloc;
+use alloc::{string::String, vec::Vec};
+use core::panic::PanicInfo;
+use embedded_audio::{AudioFile, PlatformFile, PlatformFileError, wav::Wav};
+use embedded_graphics::{
+    mono_font::{MonoTextStyle, ascii::FONT_6X10},
+    pixelcolor::Rgb565,
+    prelude::RgbColor,
+};
+use selection_ui::{SelectionUi, SelectionUiError, draw_text_center};
+use userlib::{
+    audio::{AUDIO_BUFFER_LEN, audio_buffer_ready, send_audio_buffer},
+    display::Display,
+    format,
+    fs::{Entries, file_len, list_dir, read_file},
+    get_key,
+    keyboard::{KeyCode, KeyState},
+    println,
+};
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    println!("user panic: {} @ {:?}", info.message(), info.location(),);
+    loop {}
+}
+
+#[unsafe(no_mangle)]
+pub extern "Rust" fn _start() {
+    main()
+}
+
+pub fn main() {
+    println!("Starting Wav player app");
+    let mut display = Display::take().unwrap();
+
+    loop {
+        let mut entries = Entries::new();
+        list_dir("/music", &mut entries);
+
+        let mut files = entries.entries();
+        files.retain(|e| e.extension().unwrap_or("") == "wav");
+        let mut wavs = files.iter().map(|e| e.full_name()).collect::<Vec<&str>>();
+        wavs.sort();
+
+        let mut selection_ui = SelectionUi::new(&wavs);
+        let selection = match selection_ui.run_selection_ui(&mut display) {
+            Ok(maybe_sel) => maybe_sel,
+            Err(e) => match e {
+                SelectionUiError::SelectionListEmpty => {
+                    draw_text_center(
+                        &mut display,
+                        "No Wavs were found in /music",
+                        MonoTextStyle::new(&FONT_6X10, Rgb565::RED),
+                    )
+                    .expect("Display Error");
+                    None
+                }
+                SelectionUiError::DisplayError(_) => panic!("Display Error"),
+            },
+        };
+
+        assert!(selection.is_some());
+
+        draw_text_center(
+            &mut display,
+            &format!("Now playing {}", wavs[selection.unwrap()]),
+            MonoTextStyle::new(&FONT_6X10, Rgb565::WHITE),
+        )
+        .expect("Display Error");
+
+        let file_name = format!("/music/{}", wavs[selection.unwrap()]);
+        let file = File::new(file_name);
+        let mut wav = Wav::new(file).unwrap();
+        println!("sample rate: {}", wav.sample_rate());
+        println!("channels: {:?}", wav.channels() as u8);
+
+        let mut buf = [0_u8; AUDIO_BUFFER_LEN];
+
+        loop {
+            if audio_buffer_ready() {
+                if wav.is_eof() {
+                    break;
+                }
+
+                let _read = wav.read(&mut buf).unwrap();
+                send_audio_buffer(&buf);
+            }
+
+            let event = get_key();
+            if event.state == KeyState::Released && event.key == KeyCode::Esc {
+                return;
+            }
+        }
+    }
+}
+
+struct File {
+    current_pos: usize,
+    file: String,
+}
+
+impl File {
+    fn new(file: String) -> Self {
+        Self {
+            current_pos: 0,
+            file,
+        }
+    }
+}
+
+impl PlatformFile for File {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize, PlatformFileError> {
+        let read = read_file(&self.file, self.current_pos, buf);
+        self.current_pos += read;
+        Ok(read)
+    }
+
+    fn seek_from_current(&mut self, offset: i64) -> Result<(), PlatformFileError> {
+        if offset.is_positive() {
+            self.current_pos += offset as usize;
+        } else {
+            self.current_pos -= offset as usize;
+        }
+        Ok(())
+    }
+
+    fn seek_from_start(&mut self, offset: usize) -> Result<(), PlatformFileError> {
+        self.current_pos = offset;
+        Ok(())
+    }
+
+    fn seek_from_end(&mut self, offset: usize) -> Result<(), PlatformFileError> {
+        self.current_pos = self.length() - offset;
+        Ok(())
+    }
+
+    fn length(&mut self) -> usize {
+        file_len(&self.file)
+    }
+}

userlib/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "userlib"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+userlib_sys = { path = "../userlib_sys" }
+embedded-graphics = "0.8.1"
+once_cell = { version = "1", default-features = false }
+rand_core = "0.9.3"

userlib/src/lib.rs

@@ -0,0 +1,283 @@
+#![no_std]
+#![allow(static_mut_refs)]
+
+extern crate alloc;
+
+pub use alloc::format;
+use core::alloc::{GlobalAlloc, Layout};
+use rand_core::RngCore;
+use userlib_sys::{RngRequest, keyboard::KeyEvent};
+pub use userlib_sys::{keyboard, print};
+
+#[global_allocator]
+static ALLOC: Alloc = Alloc;
+
+struct Alloc;
+
+unsafe impl GlobalAlloc for Alloc {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        userlib_sys::alloc(layout.into())
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        userlib_sys::dealloc(ptr, layout.into());
+    }
+}
+
+#[macro_export]
+macro_rules! println {
+    ($($arg:tt)*) => {{
+        let s = $crate::format!($($arg)*);
+        $crate::print(s.as_ptr(), s.len());
+    }};
+}
+
+pub fn sleep(ms: u64) {
+    userlib_sys::sleep(ms);
+}
+
+pub fn get_ms() -> u64 {
+    userlib_sys::get_ms()
+}
+
+pub fn get_key() -> KeyEvent {
+    userlib_sys::keyboard::get_key().into()
+}
+
+pub mod display {
+    use core::sync::atomic::{AtomicBool, Ordering};
+
+    use embedded_graphics::{
+        Pixel,
+        geometry::{Dimensions, Point},
+        pixelcolor::Rgb565,
+        prelude::{DrawTarget, Size},
+        primitives::Rectangle,
+    };
+    use userlib_sys::CPixel;
+
+    pub const SCREEN_WIDTH: usize = 320;
+    pub const SCREEN_HEIGHT: usize = 320;
+
+    pub type Pixel565 = Pixel<Rgb565>;
+
+    const BUF_SIZE: usize = 1024;
+    static mut BUF: [CPixel; BUF_SIZE] = [CPixel::new(); BUF_SIZE];
+
+    static DISPLAY_TAKEN: AtomicBool = AtomicBool::new(false);
+
+    pub struct Display {
+        _private: (),
+    }
+
+    impl Display {
+        /// Only one instance of Display can be taken
+        pub fn take() -> Option<Display> {
+            if DISPLAY_TAKEN
+                .compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
+                .is_ok()
+            {
+                Some(Self { _private: () })
+            } else {
+                None
+            }
+        }
+    }
+
+    impl Dimensions for Display {
+        fn bounding_box(&self) -> Rectangle {
+            Rectangle {
+                top_left: Point { x: 0, y: 0 },
+                size: Size {
+                    width: SCREEN_WIDTH as u32,
+                    height: SCREEN_HEIGHT as u32,
+                },
+            }
+        }
+    }
+
+    impl DrawTarget for Display {
+        type Color = Rgb565;
+        type Error = ();
+
+        fn draw_iter<I>(&mut self, pixels: I) -> Result<(), Self::Error>
+        where
+            I: IntoIterator<Item = Pixel<Self::Color>>,
+        {
+            let mut count = 0;
+            for p in pixels {
+                unsafe { BUF[count] = p.into() };
+                count += 1;
+
+                if count == BUF_SIZE - 1 {
+                    userlib_sys::draw_iter(unsafe { BUF.as_ptr() }, count);
+                    count = 0;
+                }
+            }
+
+            if count > 0 {
+                userlib_sys::draw_iter(unsafe { BUF.as_ptr() }, count);
+            }
+
+            Ok(())
+        }
+    }
+}
+
+fn gen_rand(req: &mut RngRequest) {
+    userlib_sys::gen_rand(req);
+}
+
+pub struct Rng;
+
+impl RngCore for Rng {
+    fn next_u32(&mut self) -> u32 {
+        let mut req = RngRequest::U32(0);
+        gen_rand(&mut req);
+        if let RngRequest::U32(i) = req {
+            return i;
+        };
+        0
+    }
+
+    fn next_u64(&mut self) -> u64 {
+        let mut req = RngRequest::U64(0);
+        gen_rand(&mut req);
+        if let RngRequest::U64(i) = req {
+            return i;
+        };
+        0
+    }
+    fn fill_bytes(&mut self, dst: &mut [u8]) {
+        let mut req = RngRequest::Bytes {
+            ptr: dst.as_mut_ptr(),
+            len: dst.len(),
+        };
+        gen_rand(&mut req);
+    }
+}
+
+pub mod fs {
+    use alloc::vec::Vec;
+    use core::fmt::Display;
+
+    pub fn read_file(file: &str, start_from: usize, buf: &mut [u8]) -> usize {
+        userlib_sys::read_file(
+            file.as_ptr(),
+            file.len(),
+            start_from,
+            buf.as_mut_ptr(),
+            buf.len(),
+        )
+    }
+
+    pub fn write_file(file: &str, start_from: usize, buf: &[u8]) {
+        userlib_sys::write_file(
+            file.as_ptr(),
+            file.len(),
+            start_from,
+            buf.as_ptr(),
+            buf.len(),
+        )
+    }
+
+    #[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+    pub struct FileName<'a> {
+        full: &'a str,
+        base: &'a str,
+        ext: Option<&'a str>,
+    }
+
+    impl<'a> FileName<'a> {
+        pub fn full_name(&self) -> &str {
+            self.full
+        }
+
+        pub fn base(&self) -> &str {
+            self.base
+        }
+
+        pub fn extension(&self) -> Option<&str> {
+            self.ext
+        }
+    }
+
+    impl<'a> Display for FileName<'a> {
+        fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+            write!(f, "{}", self.full_name())
+        }
+    }
+
+    impl<'a> From<&'a str> for FileName<'a> {
+        fn from(s: &'a str) -> FileName<'a> {
+            let full = s;
+
+            // Split on last dot for extension
+            let (base, ext) = match s.rfind('.') {
+                Some(idx) => (&s[..idx], Some(&s[idx + 1..])),
+                None => (s, None),
+            };
+
+            FileName { full, base, ext }
+        }
+    }
+
+    const MAX_ENTRY_NAME_LEN: usize = 25;
+    const MAX_ENTRIES: usize = 25;
+
+    #[derive(Clone, Copy, Debug)]
+    pub struct Entries([[u8; MAX_ENTRY_NAME_LEN]; MAX_ENTRIES]);
+
+    impl Default for Entries {
+        fn default() -> Self {
+            Self::new()
+        }
+    }
+
+    impl Entries {
+        pub fn new() -> Self {
+            Self([[0; MAX_ENTRY_NAME_LEN]; MAX_ENTRIES])
+        }
+
+        /// Get list of file names after listing
+        pub fn entries<'a>(&'a self) -> Vec<FileName<'a>> {
+            self.0
+                .iter()
+                .filter_map(|buf| {
+                    let nul_pos = buf.iter().position(|&b| b == 0).unwrap_or(buf.len());
+                    Some(core::str::from_utf8(&buf[..nul_pos]).ok()?.into())
+                })
+                .collect()
+        }
+
+        fn as_ptrs(&mut self) -> [*mut u8; MAX_ENTRIES] {
+            let mut ptrs: [*mut u8; MAX_ENTRIES] = [core::ptr::null_mut(); MAX_ENTRIES];
+            for (i, buf) in self.0.iter_mut().enumerate() {
+                ptrs[i] = buf.as_mut_ptr();
+            }
+            ptrs
+        }
+    }
+
+    pub fn list_dir(path: &str, entries: &mut Entries) -> usize {
+        userlib_sys::list_dir(
+            path.as_ptr(),
+            path.len(),
+            entries.as_ptrs().as_mut_ptr(),
+            MAX_ENTRIES,
+            MAX_ENTRY_NAME_LEN,
+        )
+    }
+
+    pub fn file_len(str: &str) -> usize {
+        userlib_sys::file_len(str.as_ptr(), str.len())
+    }
+}
+
+pub mod audio {
+    pub use userlib_sys::{AUDIO_BUFFER_LEN, AUDIO_BUFFER_SAMPLES, audio_buffer_ready};
+
+    pub fn send_audio_buffer(buf: &[u8]) {
+        userlib_sys::send_audio_buffer(buf.as_ptr(), buf.len())
+    }
+}

userlib_sys/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "userlib_sys"
+version = "0.1.0"
+edition = "2024"
+
+[features]
+default = ["alloc"]
+alloc = []
+defmt = ["dep:defmt"]
+
+[dependencies]
+strum = { version = "0.27.2", default-features = false, features = ["derive"] }
+bitflags = "2.9.4"
+embedded-graphics = "0.8.1"
+defmt = { version = "0.3", optional = true }
+
+[build-dependencies]
+cbindgen = "0.24.0"

userlib_sys/src/lib.rs

@@ -0,0 +1,499 @@
+#![no_std]
+#[cfg(feature = "alloc")]
+use core::alloc::Layout;
+
+use core::ffi::c_char;
+use embedded_graphics::{
+    Pixel,
+    pixelcolor::{Rgb565, raw::RawU16},
+    prelude::{IntoStorage, Point},
+};
+use strum::{EnumCount, EnumIter};
+
+pub type EntryFn = fn();
+
+pub const SYS_CALL_TABLE_COUNT: usize = 14;
+const _: () = assert!(SYS_CALL_TABLE_COUNT == SyscallTable::COUNT);
+
+#[derive(Clone, Copy, EnumIter, EnumCount)]
+#[repr(u8)]
+pub enum SyscallTable {
+    Alloc = 0,
+    Dealloc = 1,
+    PrintString = 2,
+    SleepMs = 3,
+    GetMs = 4,
+    DrawIter = 5,
+    GetKey = 6,
+    GenRand = 7,
+    ListDir = 8,
+    ReadFile = 9,
+    WriteFile = 10,
+    FileLen = 11,
+    AudioBufferReady = 12,
+    SendAudioBuffer = 13,
+}
+
+#[unsafe(no_mangle)]
+#[unsafe(link_section = ".syscall_table")]
+pub static mut SYS_CALL_TABLE: [usize; SYS_CALL_TABLE_COUNT] = [0; SYS_CALL_TABLE_COUNT];
+
+#[cfg(feature = "alloc")]
+#[repr(C)]
+pub struct CLayout {
+    size: usize,
+    alignment: usize,
+}
+
+#[cfg(feature = "alloc")]
+impl From<CLayout> for Layout {
+    fn from(val: CLayout) -> Self {
+        unsafe { Layout::from_size_align_unchecked(val.size, val.alignment) }
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl From<Layout> for CLayout {
+    fn from(value: Layout) -> Self {
+        Self {
+            size: value.size(),
+            alignment: value.align(),
+        }
+    }
+}
+
+pub type Alloc = extern "C" fn(layout: CLayout) -> *mut u8;
+
+#[unsafe(no_mangle)]
+pub extern "C" fn alloc(layout: CLayout) -> *mut u8 {
+    let f: Alloc = unsafe { core::mem::transmute(SYS_CALL_TABLE[SyscallTable::Alloc as usize]) };
+    f(layout)
+}
+
+pub type Dealloc = extern "C" fn(ptr: *mut u8, layout: CLayout);
+
+#[unsafe(no_mangle)]
+pub extern "C" fn dealloc(ptr: *mut u8, layout: CLayout) {
+    let f: Dealloc =
+        unsafe { core::mem::transmute(SYS_CALL_TABLE[SyscallTable::Dealloc as usize]) };
+    f(ptr, layout)
+}
+
+pub type Print = extern "C" fn(ptr: *const u8, len: usize);
+
+#[unsafe(no_mangle)]
+pub extern "C" fn print(ptr: *const u8, len: usize) {
+    let f: Print =
+        unsafe { core::mem::transmute(SYS_CALL_TABLE[SyscallTable::PrintString as usize]) };
+    f(ptr, len);
+}
+
+pub type SleepMs = extern "C" fn(ms: u64);
+
+#[unsafe(no_mangle)]
+pub extern "C" fn sleep(ms: u64) {
+    let f: SleepMs =
+        unsafe { core::mem::transmute(SYS_CALL_TABLE[SyscallTable::SleepMs as usize]) };
+    f(ms);
+}
+
+pub type GetMs = extern "C" fn() -> u64;
+
+#[unsafe(no_mangle)]
+pub extern "C" fn get_ms() -> u64 {
+    let f: GetMs = unsafe { core::mem::transmute(SYS_CALL_TABLE[SyscallTable::GetMs as usize]) };
+    f()
+}
+
+#[repr(C)]
+#[derive(Default, Copy, Clone)]
+pub struct CPixel {
+    pub x: i32,
+    pub y: i32,
+    pub color: u16,
+}
+
+impl CPixel {
+    pub const fn new() -> Self {
+        Self {
+            x: 0,
+            y: 0,
+            color: 0,
+        }
+    }
+}
+
+impl From<CPixel> for Pixel<Rgb565> {
+    fn from(value: CPixel) -> Self {
+        Pixel(
+            Point::new(value.x, value.y),
+            RawU16::new(value.color).into(),
+        )
+    }
+}
+
+impl From<Pixel<Rgb565>> for CPixel {
+    fn from(value: Pixel<Rgb565>) -> Self {
+        CPixel {
+            x: value.0.x,
+            y: value.0.y,
+            color: value.1.into_storage(),
+        }
+    }
+}
+
+pub type DrawIter = extern "C" fn(ptr: *const CPixel, len: usize);
+
+#[unsafe(no_mangle)]
+pub extern "C" fn draw_iter(ptr: *const CPixel, len: usize) {
+    let f: DrawIter =
+        unsafe { core::mem::transmute(SYS_CALL_TABLE[SyscallTable::DrawIter as usize]) };
+    f(ptr, len);
+}
+
+pub mod keyboard {
+    use crate::{SYS_CALL_TABLE, SyscallTable};
+
+    bitflags::bitflags! {
+        #[derive(Default, Debug, PartialEq, Eq, Clone, Copy)]
+        #[repr(C)]
+        pub struct Modifiers: u8 {
+            const NONE = 0;
+            const CTRL = 1;
+            const ALT = 2;
+            const LSHIFT = 4;
+            const RSHIFT = 8;
+            const SYM = 16;
+        }
+    }
+
+    #[repr(C)]
+    pub struct KeyEventC {
+        pub key: u8,
+        pub state: KeyState,
+        pub mods: Modifiers,
+    }
+
+    impl From<KeyEventC> for KeyEvent {
+        fn from(val: KeyEventC) -> Self {
+            KeyEvent {
+                key: val.key.into(),
+                state: val.state,
+                mods: val.mods,
+            }
+        }
+    }
+
+    #[derive(Debug)]
+    pub struct KeyEvent {
+        pub key: KeyCode,
+        pub state: KeyState,
+        pub mods: Modifiers,
+    }
+
+    impl From<KeyEvent> for KeyEventC {
+        fn from(val: KeyEvent) -> Self {
+            KeyEventC {
+                key: val.key.into(),
+                state: val.state,
+                mods: val.mods,
+            }
+        }
+    }
+
+    #[cfg_attr(feature = "defmt", derive(defmt::Format))]
+    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+    #[repr(C)]
+    pub enum KeyState {
+        Idle = 0,
+        Pressed = 1,
+        Hold = 2,
+        Released = 3,
+    }
+
+    impl From<u8> for KeyState {
+        fn from(value: u8) -> Self {
+            match value {
+                1 => KeyState::Pressed,
+                2 => KeyState::Hold,
+                3 => KeyState::Released,
+                0 | _ => KeyState::Idle,
+            }
+        }
+    }
+
+    #[cfg_attr(feature = "defmt", derive(defmt::Format))]
+    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+    #[repr(u8)]
+    pub enum KeyCode {
+        JoyUp = 0x01,
+        JoyDown = 0x02,
+        JoyLeft = 0x03,
+        JoyRight = 0x04,
+        JoyCenter = 0x05,
+        BtnLeft1 = 0x06,
+        BtnRight1 = 0x07,
+        BtnLeft2 = 0x11,
+        BtnRight2 = 0x12,
+        Backspace = 0x08,
+        Tab = 0x09,
+        Enter = 0x0A,
+        ModAlt = 0xA1,
+        ModShiftLeft = 0xA2,
+        ModShiftRight = 0xA3,
+        ModSym = 0xA4,
+        ModCtrl = 0xA5,
+        Esc = 0xB1,
+        Left = 0xB4,
+        Up = 0xB5,
+        Down = 0xB6,
+        Right = 0xB7,
+        Break = 0xD0,
+        Insert = 0xD1,
+        Home = 0xD2,
+        Del = 0xD4,
+        End = 0xD5,
+        PageUp = 0xD6,
+        PageDown = 0xD7,
+        CapsLock = 0xC1,
+        F1 = 0x81,
+        F2 = 0x82,
+        F3 = 0x83,
+        F4 = 0x84,
+        F5 = 0x85,
+        F6 = 0x86,
+        F7 = 0x87,
+        F8 = 0x88,
+        F9 = 0x89,
+        F10 = 0x90,
+        Char(char),
+        Unknown(u8),
+    }
+
+    impl From<KeyCode> for u8 {
+        fn from(val: KeyCode) -> Self {
+            match val {
+                KeyCode::JoyUp => 0x01,
+                KeyCode::JoyDown => 0x02,
+                KeyCode::JoyLeft => 0x03,
+                KeyCode::JoyRight => 0x04,
+                KeyCode::JoyCenter => 0x05,
+                KeyCode::BtnLeft1 => 0x06,
+                KeyCode::BtnRight1 => 0x07,
+                KeyCode::BtnLeft2 => 0x11,
+                KeyCode::BtnRight2 => 0x12,
+                KeyCode::Backspace => 0x08,
+                KeyCode::Tab => 0x09,
+                KeyCode::Enter => 0x0A,
+                KeyCode::ModAlt => 0xA1,
+                KeyCode::ModShiftLeft => 0xA2,
+                KeyCode::ModShiftRight => 0xA3,
+                KeyCode::ModSym => 0xA4,
+                KeyCode::ModCtrl => 0xA5,
+                KeyCode::Esc => 0xB1,
+                KeyCode::Left => 0xB4,
+                KeyCode::Up => 0xB5,
+                KeyCode::Down => 0xB6,
+                KeyCode::Right => 0xB7,
+                KeyCode::Break => 0xD0,
+                KeyCode::Insert => 0xD1,
+                KeyCode::Home => 0xD2,
+                KeyCode::Del => 0xD4,
+                KeyCode::End => 0xD5,
+                KeyCode::PageUp => 0xD6,
+                KeyCode::PageDown => 0xD7,
+                KeyCode::CapsLock => 0xC1,
+                KeyCode::F1 => 0x81,
+                KeyCode::F2 => 0x82,
+                KeyCode::F3 => 0x83,
+                KeyCode::F4 => 0x84,
+                KeyCode::F5 => 0x85,
+                KeyCode::F6 => 0x86,
+                KeyCode::F7 => 0x87,
+                KeyCode::F8 => 0x88,
+                KeyCode::F9 => 0x89,
+                KeyCode::F10 => 0x90,
+                KeyCode::Char(char) => char as u8,
+                KeyCode::Unknown(i) => i,
+            }
+        }
+    }
+
+    impl From<u8> for KeyCode {
+        fn from(value: u8) -> Self {
+            match value {
+                0x01 => Self::JoyUp,
+                0x02 => Self::JoyDown,
+                0x03 => Self::JoyLeft,
+                0x04 => Self::JoyRight,
+                0x05 => Self::JoyCenter,
+                0x06 => Self::BtnLeft1,
+                0x07 => Self::BtnRight1,
+                0x08 => Self::Backspace,
+                0x09 => Self::Tab,
+                0x0A => Self::Enter,
+                0x11 => Self::BtnLeft2,
+                0x12 => Self::BtnRight2,
+                0xA1 => Self::ModAlt,
+                0xA2 => Self::ModShiftLeft,
+                0xA3 => Self::ModShiftRight,
+                0xA4 => Self::ModSym,
+                0xA5 => Self::ModCtrl,
+                0xB1 => Self::Esc,
+                0xB4 => Self::Left,
+                0xB5 => Self::Up,
+                0xB6 => Self::Down,
+                0xB7 => Self::Right,
+                0xC1 => Self::CapsLock,
+                0xD0 => Self::Break,
+                0xD1 => Self::Insert,
+                0xD2 => Self::Home,
+                0xD4 => Self::Del,
+                0xD5 => Self::End,
+                0xD6 => Self::PageUp,
+                0xD7 => Self::PageDown,
+                0x81 => Self::F1,
+                0x82 => Self::F2,
+                0x83 => Self::F3,
+                0x84 => Self::F4,
+                0x85 => Self::F5,
+                0x86 => Self::F6,
+                0x87 => Self::F7,
+                0x88 => Self::F8,
+                0x89 => Self::F9,
+                0x90 => Self::F10,
+                _ => match char::from_u32(value as u32) {
+                    Some(c) => Self::Char(c),
+                    None => Self::Unknown(value),
+                },
+            }
+        }
+    }
+
+    pub type GetKey = extern "C" fn() -> KeyEventC;
+
+    #[unsafe(no_mangle)]
+    pub extern "C" fn get_key() -> KeyEventC {
+        let f: GetKey =
+            unsafe { core::mem::transmute(SYS_CALL_TABLE[SyscallTable::GetKey as usize]) };
+        f()
+    }
+}
+
+#[repr(C)]
+pub enum RngRequest {
+    U32(u32),
+    U64(u64),
+    Bytes { ptr: *mut u8, len: usize },
+}
+
+pub type GenRand = extern "C" fn(req: &mut RngRequest);
+
+#[unsafe(no_mangle)]
+pub extern "C" fn gen_rand(req: &mut RngRequest) {
+    unsafe {
+        let ptr = SYS_CALL_TABLE[SyscallTable::GenRand as usize];
+        let f: GenRand = core::mem::transmute(ptr);
+        f(req)
+    }
+}
+
+pub type ListDir = extern "C" fn(
+    str: *const u8,
+    len: usize,
+    entries: *mut *mut c_char,
+    file_len: usize,
+    max_entry_str_len: usize,
+) -> usize;
+
+#[unsafe(no_mangle)]
+pub extern "C" fn list_dir(
+    str: *const u8,
+    len: usize,
+    entries: *mut *mut c_char,
+    entry_count: usize,
+    max_entry_str_len: usize,
+) -> usize {
+    unsafe {
+        let ptr = SYS_CALL_TABLE[SyscallTable::ListDir as usize];
+        let f: ListDir = core::mem::transmute(ptr);
+        f(str, len, entries, entry_count, max_entry_str_len)
+    }
+}
+
+pub type ReadFile = extern "C" fn(
+    str: *const u8,
+    len: usize,
+    read_from: usize,
+    buf: *mut u8,
+    buf_len: usize,
+) -> usize;
+
+#[unsafe(no_mangle)]
+pub extern "C" fn read_file(
+    str: *const u8,
+    len: usize,
+    read_from: usize,
+    buf: *mut u8,
+    buf_len: usize,
+) -> usize {
+    unsafe {
+        let ptr = SYS_CALL_TABLE[SyscallTable::ReadFile as usize];
+        let f: ReadFile = core::mem::transmute(ptr);
+        f(str, len, read_from, buf, buf_len)
+    }
+}
+
+pub type WriteFile =
+    extern "C" fn(str: *const u8, len: usize, write_from: usize, buf: *const u8, buf_len: usize);
+
+#[unsafe(no_mangle)]
+pub extern "C" fn write_file(
+    str: *const u8,
+    len: usize,
+    write_from: usize,
+    buf: *const u8,
+    buf_len: usize,
+) {
+    unsafe {
+        let ptr = SYS_CALL_TABLE[SyscallTable::WriteFile as usize];
+        let f: WriteFile = core::mem::transmute(ptr);
+        f(str, len, write_from, buf, buf_len)
+    }
+}
+
+pub type FileLen = extern "C" fn(str: *const u8, len: usize) -> usize;
+
+#[unsafe(no_mangle)]
+pub extern "C" fn file_len(str: *const u8, len: usize) -> usize {
+    unsafe {
+        let ptr = SYS_CALL_TABLE[SyscallTable::FileLen as usize];
+        let f: FileLen = core::mem::transmute(ptr);
+        f(str, len)
+    }
+}
+
+pub type AudioBufferReady = extern "C" fn() -> bool;
+
+#[allow(unused)]
+pub fn audio_buffer_ready() -> bool {
+    unsafe {
+        let ptr = SYS_CALL_TABLE[SyscallTable::AudioBufferReady as usize];
+        let f: AudioBufferReady = core::mem::transmute(ptr);
+        f()
+    }
+}
+
+pub const AUDIO_BUFFER_SAMPLES: usize = 1024;
+pub const AUDIO_BUFFER_LEN: usize = AUDIO_BUFFER_SAMPLES * 2;
+
+pub type SendAudioBuffer = extern "C" fn(ptr: *const u8, len: usize);
+
+#[allow(unused)]
+pub fn send_audio_buffer(buf: *const u8, len: usize) {
+    unsafe {
+        let ptr = SYS_CALL_TABLE[SyscallTable::SendAudioBuffer as usize];
+        let f: SendAudioBuffer = core::mem::transmute(ptr);
+        f(buf, len)
+    }
+}