Cargo.lock

@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "bitfrob"
@@ -10,18 +10,25 @@ checksum = "5a96c7c818dc8807bb1982dd2cba4c7de0ed6eba4ffb5fc24321d1b38676a120"
 
 [[package]]
 name = "bracer"
-version = "0.1.2"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6559b8c3065745016f5cc2d1095273fe8a175e953c976426947ad828d6ba6fda"
+checksum = "00248d542917c4ef013367c0907300e9befbbc1f99b12938c9e5a356ab50582d"
+
+[[package]]
+name = "bytemuck"
+version = "1.23.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9134a6ef01ce4b366b50689c94f82c14bc72bc5d0386829828a2e2752ef7958c"
 
 [[package]]
 name = "gba"
-version = "0.11.3"
+version = "0.14.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7ab90d1de12c1323d80d9850c55d68931512ef7f0462a8c79e92b726f5037ad6"
+checksum = "dff72a04df599de9991069ab6807f00e02dc24840e13d16f92dfa2929c4e6950"
 dependencies = [
  "bitfrob",
  "bracer",
+ "bytemuck",
  "voladdress",
 ]
 

Cargo.toml

@@ -1,9 +1,13 @@
 [package]
 name = "gba-template"
 version = "0.1.0"
-edition = "2021"
+edition = "2024"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-gba = "0.11.3"
+gba = "0.14.1"
+
+[profile.release]
+opt-level = 3
+
+[profile.dev]
+opt-level = "s"

make-rom.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+# terrible
+eval $(grep '^name *=' Cargo.toml | head -n1 | sed 's/ //g')
+eval $(grep '^target *=' .cargo/config.toml | head -n1 | sed 's/ //g')
+
+# terribler
+export RUSTC_BOOTSTRAP=1
+
+next_arg=false
+for arg in "$@"; do
+  if $next_arg; then
+    target="$arg"
+    next_arg=false
+  elif [ "$arg" == "--target" ]; then
+    next_arg=true
+  elif [[ "$arg" =~ ^--target= ]]; then
+    target="${arg/--target=/}"
+  fi
+done
+
+set -exo pipefail
+
+cargo -Z build-std build --release "$@"
+
+arm-none-eabi-objcopy -O binary "target/${target}/release/$name" "target/${name}.gba"
+
+which gbafix || cargo install gbafix
+
+gbafix "target/${name}.gba"

run-release.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+# terrible
+export RUSTC_BOOTSTRAP=1
+
+set -ex
+exec cargo -Z build-std run --release "$@"

src/halfwidth.rs

@@ -1,136 +0,0 @@
-use core::fmt::Write;
-use gba::prelude::*;
-
-const FONT_WIDTH: usize = 4;
-const FONT_HEIGHT: usize = 6;
-const TAB_CHARS: usize = 4;
-
-const MAP_WIDTH: usize = 32;
-const MAP_HEIGHT: usize = 32;
-const WRAP_COL: usize = 60;
-
-// 96 printable ascii chars, each using half of a 8x8 4bpp tile
-#[link_section = ".ewram"]
-static LIFONT: [u8; 96 * 16] = *include_bytes!("lifont-3x5.4bpp");
-
-type DoubleHalfTile = [u16; 2 * 8];
-
-fn font() -> &'static [DoubleHalfTile] {
-    unsafe { core::slice::from_raw_parts(LIFONT.as_ptr() as *const DoubleHalfTile, 96 / 2) }
-}
-
-fn charblock_write(tile_index: usize, tile_row_index: usize, value: u16) {
-    unsafe {
-        let tile_ptr = (CHARBLOCK0_4BPP.as_ptr() as *mut DoubleHalfTile).add(tile_index);
-        (*tile_ptr)
-            .as_mut_ptr()
-            .add(tile_row_index)
-            .write_volatile(value);
-    }
-}
-
-// TODO: support for drawing to a region of the charblock/screenblock
-// (i.e. not necessarily taking over the whole display)
-pub struct TextPainter {
-    pixel_row: usize,
-    pixel_col: usize,
-}
-
-impl core::fmt::Write for TextPainter {
-    fn write_str(&mut self, text: &str) -> core::fmt::Result {
-        for c in text
-            .chars()
-            .map(|c| c.as_ascii().map(|a| a.to_u8()).unwrap_or(0x7f) as usize)
-        {
-            if self.pixel_col >= FONT_WIDTH * WRAP_COL {
-                self.pixel_row += FONT_HEIGHT;
-                self.pixel_col = 0;
-            }
-            if (self.pixel_row >> 3) > MAP_HEIGHT {
-                return Err(core::fmt::Error::default());
-            }
-            if c < 0x20 {
-                match c as u8 {
-                    // '\b', backspace
-                    8 => {
-                        self.pixel_col = self.pixel_col.saturating_sub(FONT_WIDTH);
-                    }
-                    b'\t' => {
-                        self.pixel_col =
-                            (self.pixel_col + 1).next_multiple_of(TAB_CHARS * FONT_WIDTH);
-                    }
-                    b'\n' => {
-                        self.pixel_row += FONT_HEIGHT;
-                        self.pixel_col = 0; // assume cooked
-                    }
-                    b'\r' => {
-                        self.pixel_col = 0;
-                    }
-                    _ => {} // TODO?
-                }
-            } else {
-                let font_tile = &font()[(c - 0x20) >> 1];
-                let out_tile_col = self.pixel_col >> 3;
-                let mut out_pixel_row = self.pixel_row;
-                for font_row in font_tile
-                    .iter()
-                    .skip(c & 1)
-                    .step_by(2)
-                    .take(FONT_HEIGHT)
-                    .copied()
-                {
-                    let out_tile_row = out_pixel_row >> 3;
-                    let out_tile_pixel_row =
-                        ((out_pixel_row & 7) << 1) + ((self.pixel_col & 4) >> 2);
-                    let idx = out_tile_row * MAP_WIDTH + out_tile_col;
-                    charblock_write(idx, out_tile_pixel_row, font_row);
-                    out_pixel_row += 1;
-                }
-                self.pixel_col += FONT_WIDTH;
-            }
-        }
-        Ok(())
-    }
-}
-
-impl TextPainter {
-    pub const fn new() -> Self {
-        Self {
-            pixel_row: 0,
-            pixel_col: 0,
-        }
-    }
-
-    pub fn setup_display(&mut self) {
-        self.pixel_row = 0;
-        self.pixel_col = 0;
-        let dispcnt = DisplayControl::new().with_show_bg0(true);
-        DISPCNT.write(dispcnt);
-        let bg0cnt = BackgroundControl::new()
-            .with_size(0)
-            .with_charblock(0)
-            .with_screenblock(16);
-        BG0CNT.write(bg0cnt);
-        BG0HOFS.write(0);
-        BG0VOFS.write(0);
-        let screenblock = TEXT_SCREENBLOCKS.get_frame(16).unwrap();
-        let mut x = 0;
-        for r in 0..32 {
-            let row = screenblock.get_row(r).unwrap();
-            for cell in row.iter() {
-                cell.write(TextEntry::new().with_tile(x));
-                x += 1;
-            }
-        }
-        for tile in CHARBLOCK0_4BPP.iter() {
-            tile.write([0; 8]);
-        }
-        BG_PALETTE
-            .index(1)
-            .write(Color::new().with_red(22).with_green(16).with_blue(16));
-        BG_PALETTE
-            .index(2)
-            .write(Color::new().with_red(31).with_green(31).with_blue(31));
-        BG_PALETTE.index(0).write(Color::new().with_red(8));
-    }
-}

src/main.rs

@@ -1,137 +1,64 @@
-// from https://github.com/rust-console/gba/blob/main/examples/hello.rs
 #![no_std]
 #![no_main]
-#![feature(ascii_char)]
+#![cfg_attr(test, feature(custom_test_frameworks))]
-#![feature(panic_info_message)]
+#![cfg_attr(test, test_runner(test_harness::test_runner))]
-// rustc is simply wrong about core::fmt::Write being unused,
+#![cfg_attr(test, reexport_test_harness_main = "test_main")]
-// it's used in the panic handler.
-#![allow(unused_imports)]
 
-mod halfwidth;
+#[cfg(test)]
-
+mod test_harness;
-use core::fmt::Write;
 
+use core::panic::PanicInfo;
 use gba::prelude::*;
 
 #[allow(unused_must_use)]
-#[panic_handler]
+#[cfg_attr(not(test), unsafe(no_mangle))]
-fn panic_handler(info: &core::panic::PanicInfo) -> ! {
+#[instruction_set(arm::t32)]
-    let mut text_painter = halfwidth::TextPainter::new();
-    text_painter.setup_display();
-
-    text_painter.write_str("panic at ");
-    if let Some(location) = info.location() {
-        write!(&mut text_painter, "{}:{}", location.file(), location.line());
-    } else {
-        text_painter.write_str("unknown location");
-    };
-    if let Some(msg) = info.message() {
-        write!(&mut text_painter, ":\n");
-        core::fmt::write(&mut text_painter, *msg);
-    }
-    if let Some(s) = info.payload().downcast_ref::<&str>() {
-        text_painter.write_str("\n");
-        text_painter.write_str(s);
-    }
-    #[cfg(debug_assertions)]
-    if let Ok(mut logger) = MgbaBufferedLogger::try_new(MgbaMessageLevel::Fatal) {
-        for _ in 0..4 {
-            VBlankIntrWait();
-        }
-        if let Some(args) = info.message() {
-            logger.write_fmt(*args);
-        } else {
-            writeln!(logger, "{info}");
-        }
-    }
-    loop {
-        VBlankIntrWait();
-    }
-}
-
-#[link_section = ".ewram"]
-static FRAME_KEYS: GbaCell<KeyInput> = GbaCell::new(KeyInput::new());
-
-#[link_section = ".iwram"]
-extern "C" fn irq_handler(_: IrqBits) {
-    // We'll read the keys during vblank and store it for later.
-    FRAME_KEYS.write(KEYINPUT.read());
-}
-
-#[no_mangle]
 extern "C" fn main() -> ! {
-    RUST_IRQ_HANDLER.write(Some(irq_handler));
+    BG_PALETTE.index(0).write(Color(0x7F2B)); // blue
-    DISPSTAT.write(DisplayStatus::new().with_irq_vblank(true));
+    BG_PALETTE.index(1).write(Color(0x5EBE)); // pink
-    IE.write(IrqBits::VBLANK);
+    BG_PALETTE.index(2).write(Color(0x7FFF)); // white
-    IME.write(true);
 
-    if let Ok(mut logger) = MgbaBufferedLogger::try_new(MgbaMessageLevel::Debug) {
+    // rotate and streeetch
-        writeln!(logger, "hello!").ok();
+    BG2PA.write(i16fx8::from_bits(0));
+    BG2PB.write(i16fx8::from_bits(8));
+    BG2PC.write(i16fx8::from_bits(1));
+    BG2PD.write(i16fx8::from_bits(0));
 
-        let fx_u: Fixed<u32, 8> = Fixed::<u32, 8>::wrapping_from(7) + Fixed::<u32, 8>::from_raw(12);
+    // load-bearing low-order 00 byte (it's a blue pixel and a tile ID)
-        writeln!(logger, "fixed unsigned: {fx_u:?}").ok();
+    unsafe { CHARBLOCK0_8BPP.index(0).cast() }.write(0x01020100);
 
-        let fx_i1: Fixed<i32, 8> =
+    DISPCNT.write(
-            Fixed::<i32, 8>::wrapping_from(8) + Fixed::<i32, 8>::from_raw(15);
+        DisplayControl::new()
-        writeln!(logger, "fixed signed positive: {fx_i1:?}").ok();
+            .with_video_mode(VideoMode::_2)
+            .with_show_bg2(true),
+    );
 
-        let fx_i2: Fixed<i32, 8> = Fixed::<i32, 8>::wrapping_from(0)
+    // waits forever, as we haven't enabled interrupts
-            - Fixed::<i32, 8>::wrapping_from(3)
+    VBlankIntrWait();
-            - Fixed::<i32, 8>::from_raw(17);
+    unreachable!();
-        writeln!(logger, "fixed signed negative: {fx_i2:?}").ok();
 }
 
-    {
+#[cfg_attr(not(test), panic_handler)]
-        // get our tile data into memory.
+#[cfg_attr(test, allow(unused))]
-        Cga8x8Thick.bitunpack_4bpp(CHARBLOCK0_4BPP.as_region(), 0);
+fn panic_handler(panic_info: &PanicInfo) -> ! {
+    #[cfg(debug_assertions)]
+    if let Ok(mut log) = MgbaBufferedLogger::try_new(MgbaMessageLevel::Fatal) {
+        use core::fmt::Write;
+        if let Some(loc) = panic_info.location() {
+            log.write_fmt(format_args!("{loc}: ")).ok();
         }
-
+        log.write_fmt(format_args!("{}", panic_info.message())).ok();
-    {
-        // set up the tilemap
-        let tsb = TEXT_SCREENBLOCKS.get_frame(31).unwrap();
-        for y in 0..16 {
-            let row = tsb.get_row(y).unwrap();
-            for (x, addr) in row.iter().enumerate().take(16) {
-                let te = TextEntry::new().with_tile((y * 16 + x) as u16);
-                addr.write(te);
     }
-        }
+    let _ = panic_info;
-    }
-
-    {
-        // Set BG0 to use the tilemap we just made, and set it to be shown.
-        BG0CNT.write(BackgroundControl::new().with_screenblock(31));
-        DISPCNT.write(DisplayControl::new().with_show_bg0(true));
-    }
-
-    let mut x_off = 0_u32;
-    let mut y_off = 0_u32;
-    let mut backdrop_color = Color(0);
     loop {
         VBlankIntrWait();
-        // show current frame
-        BACKDROP_COLOR.write(backdrop_color);
-        BG0HOFS.write(x_off as u16);
-        BG0VOFS.write(y_off as u16);
-
-        // prep next frame
-        let k = FRAME_KEYS.read();
-        backdrop_color = Color(k.to_u16());
-        if k.up() {
-            y_off = y_off.wrapping_add(1);
     }
-        if k.down() {
-            y_off = y_off.wrapping_sub(1);
-        }
-        if k.left() {
-            x_off = x_off.wrapping_add(1);
-        }
-        if k.right() {
-            x_off = x_off.wrapping_sub(1);
 }
 
-        if k.start() {
+#[cfg(test)]
-            panic!("pressed start")
+mod tests {
-        }
+    #[test_case]
+    fn it_works() {
+        assert_eq!(1 + 1, 2);
     }
 }

src/test_harness.rs

@@ -0,0 +1,99 @@
+use core::fmt::Write;
+use gba::{bios, mem, mgba, prelude::*};
+
+#[panic_handler]
+fn panic(info: &core::panic::PanicInfo) -> ! {
+    DISPSTAT.write(DisplayStatus::new().with_irq_vblank(true));
+    BG_PALETTE.index(0).write(Color::from_rgb(25, 10, 5));
+    IE.write(IrqBits::VBLANK);
+    IME.write(true);
+    VBlankIntrWait();
+    VBlankIntrWait();
+    VBlankIntrWait();
+
+    // the Fatal one kills emulation after one line / 256 bytes
+    // so emit all the information as Error first
+    if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Error) {
+        writeln!(log, "[failed]").ok();
+        write!(log, "{}", info).ok();
+    }
+
+    if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Fatal) {
+        if let Some(loc) = info.location() {
+            write!(log, "panic at {loc}! see mgba error log for details.").ok();
+        } else {
+            write!(log, "panic! see mgba error log for details.").ok();
+        }
+    }
+
+    IE.write(IrqBits::new());
+    bios::IntrWait(true, IrqBits::new());
+    loop {}
+}
+
+pub(crate) trait UnitTest {
+    fn run(&self);
+}
+
+impl<T: Fn()> UnitTest for T {
+    fn run(&self) {
+        if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Info) {
+            write!(log, "{}...", core::any::type_name::<T>()).ok();
+        }
+
+        self();
+
+        if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Info) {
+            writeln!(log, "[ok]").ok();
+        }
+    }
+}
+
+pub(crate) fn test_runner(tests: &[&dyn UnitTest]) {
+    if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Info) {
+        write!(log, "Running {} tests", tests.len()).ok();
+    }
+
+    for test in tests {
+        test.run();
+    }
+    if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Info) {
+        write!(log, "Tests finished successfully").ok();
+    }
+}
+
+#[unsafe(no_mangle)]
+extern "C" fn main() {
+    DISPCNT.write(DisplayControl::new().with_video_mode(VideoMode::_0));
+    BG_PALETTE.index(0).write(Color::new());
+
+    crate::test_main();
+
+    BG_PALETTE.index(0).write(Color::from_rgb(5, 15, 25));
+    BG_PALETTE.index(1).write(Color::new());
+    BG0CNT.write(
+        BackgroundControl::new()
+            .with_charblock(0)
+            .with_screenblock(31),
+    );
+    DISPCNT.write(
+        DisplayControl::new()
+            .with_video_mode(VideoMode::_0)
+            .with_show_bg0(true),
+    );
+
+    // some niceties for people without mgba-test-runner
+    let tsb = TEXT_SCREENBLOCKS.get_frame(31).unwrap();
+    unsafe {
+        mem::set_u32x80_unchecked(tsb.into_block::<1024>().as_mut_ptr().cast(), 0, 12);
+    }
+    Cga8x8Thick.bitunpack_4bpp(CHARBLOCK0_4BPP.as_region(), 0);
+
+    let row = tsb.get_row(9).unwrap().iter().skip(6);
+    for (addr, ch) in row.zip(b"all tests passed!") {
+        addr.write(TextEntry::new().with_tile(*ch as u16));
+    }
+
+    DISPSTAT.write(DisplayStatus::new());
+    bios::IntrWait(true, IrqBits::new());
+}

unit-tests.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+export CARGO_TARGET_THUMBV4T_NONE_EABI_RUNNER=mgba-test-runner
+export CARGO_TARGET_ARMV4T_NONE_EABI_RUNNER=mgba-test-runner
+# terrible
+export RUSTC_BOOTSTRAP=1
+
+set -exo pipefail
+
+# terrible
+if ! which mgba-test-runner; then
+  pkg-config libelf
+  cargo install --git https://github.com/agbrs/agb --rev a7f9fdf01118a7a77d4dcf72f2b74a1961458b36 mgba-test-runner
+fi
+
+cargo -Z build-std test "$@"