Cargo.lock

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

Cargo.toml

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

make-rom.sh

@@ -1,30 +0,0 @@
-#!/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

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

src/halfwidth.rs

@@ -0,0 +1,136 @@
+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

@@ -1,64 +1,137 @@
+// from https://github.com/rust-console/gba/blob/main/examples/hello.rs
 #![no_std]
 #![no_main]
-#![cfg_attr(test, feature(custom_test_frameworks))]
-#![cfg_attr(test, test_runner(test_harness::test_runner))]
-#![cfg_attr(test, reexport_test_harness_main = "test_main")]
+#![feature(ascii_char)]
+#![feature(panic_info_message)]
+// rustc is simply wrong about core::fmt::Write being unused,
+// it's used in the panic handler.
+#![allow(unused_imports)]
 
-#[cfg(test)]
-mod test_harness;
+mod halfwidth;
+
+use core::fmt::Write;
 
-use core::panic::PanicInfo;
 use gba::prelude::*;
 
 #[allow(unused_must_use)]
-#[cfg_attr(not(test), unsafe(no_mangle))]
-#[instruction_set(arm::t32)]
-extern "C" fn main() -> ! {
-    BG_PALETTE.index(0).write(Color(0x7F2B)); // blue
-    BG_PALETTE.index(1).write(Color(0x5EBE)); // pink
-    BG_PALETTE.index(2).write(Color(0x7FFF)); // white
+#[panic_handler]
+fn panic_handler(info: &core::panic::PanicInfo) -> ! {
+    let mut text_painter = halfwidth::TextPainter::new();
+    text_painter.setup_display();
 
-    // rotate and streeetch
-    BG2PA.write(i16fx8::from_bits(0));
-    BG2PB.write(i16fx8::from_bits(8));
-    BG2PC.write(i16fx8::from_bits(1));
-    BG2PD.write(i16fx8::from_bits(0));
-
-    // load-bearing low-order 00 byte (it's a blue pixel and a tile ID)
-    unsafe { CHARBLOCK0_8BPP.index(0).cast() }.write(0x01020100);
-
-    DISPCNT.write(
-        DisplayControl::new()
-            .with_video_mode(VideoMode::_2)
-            .with_show_bg2(true),
-    );
-
-    // waits forever, as we haven't enabled interrupts
-    VBlankIntrWait();
-    unreachable!();
-}
-
-#[cfg_attr(not(test), panic_handler)]
-#[cfg_attr(test, allow(unused))]
-fn panic_handler(panic_info: &PanicInfo) -> ! {
+    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 log) = MgbaBufferedLogger::try_new(MgbaMessageLevel::Fatal) {
-        use core::fmt::Write;
-        if let Some(loc) = panic_info.location() {
-            log.write_fmt(format_args!("{loc}: ")).ok();
+    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}");
         }
-        log.write_fmt(format_args!("{}", panic_info.message())).ok();
     }
-    let _ = panic_info;
     loop {
         VBlankIntrWait();
     }
 }
 
-#[cfg(test)]
-mod tests {
-    #[test_case]
-    fn it_works() {
-        assert_eq!(1 + 1, 2);
+#[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));
+    DISPSTAT.write(DisplayStatus::new().with_irq_vblank(true));
+    IE.write(IrqBits::VBLANK);
+    IME.write(true);
+
+    if let Ok(mut logger) = MgbaBufferedLogger::try_new(MgbaMessageLevel::Debug) {
+        writeln!(logger, "hello!").ok();
+
+        let fx_u: Fixed<u32, 8> = Fixed::<u32, 8>::wrapping_from(7) + Fixed::<u32, 8>::from_raw(12);
+        writeln!(logger, "fixed unsigned: {fx_u:?}").ok();
+
+        let fx_i1: Fixed<i32, 8> =
+            Fixed::<i32, 8>::wrapping_from(8) + Fixed::<i32, 8>::from_raw(15);
+        writeln!(logger, "fixed signed positive: {fx_i1:?}").ok();
+
+        let fx_i2: Fixed<i32, 8> = Fixed::<i32, 8>::wrapping_from(0)
+            - Fixed::<i32, 8>::wrapping_from(3)
+            - Fixed::<i32, 8>::from_raw(17);
+        writeln!(logger, "fixed signed negative: {fx_i2:?}").ok();
+    }
+
+    {
+        // get our tile data into memory.
+        Cga8x8Thick.bitunpack_4bpp(CHARBLOCK0_4BPP.as_region(), 0);
+    }
+
+    {
+        // 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);
+            }
+        }
+    }
+
+    {
+        // 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() {
+            panic!("pressed start")
+        }
     }
 }

src/test_harness.rs

@@ -1,99 +0,0 @@
-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

@@ -1,16 +0,0 @@
-#!/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 "$@"