we can make a little cyan guy show up on the screen.

examples/foo.txt

@@ -1 +1 @@
-foo_
+foo

examples/game.rs

@@ -0,0 +1,47 @@
+#![no_std]
+#![no_main]
+
+use core::fmt::Write;
+use gba::prelude::*;
+
+#[panic_handler]
+fn panic_handler(info: &core::panic::PanicInfo) -> ! {
+  if let Ok(mut logger) = MgbaBufferedLogger::try_new(MgbaMessageLevel::Fatal) {
+    writeln!(logger, "{info}").ok();
+  }
+  loop {}
+}
+
+#[no_mangle]
+extern "C" fn main() -> ! {
+  DISPSTAT.write(DisplayStatus::new().with_irq_vblank(true));
+  IE.write(IrqBits::VBLANK);
+  IME.write(true);
+
+  TIMER0_CONTROL.write(TimerControl::new().with_enabled(true));
+
+  Cga8x8Thick.bitunpack_4bpp(CHARBLOCK0_4BPP.as_region(), 0);
+  Cga8x8Thick.bitunpack_4bpp(OBJ_TILES.as_region(), 0);
+  BG_PALETTE.index(1).write(Color::MAGENTA);
+  OBJ_PALETTE.index(1).write(Color::CYAN);
+
+  let no_display = ObjAttr0::new().with_style(ObjDisplayStyle::NotDisplayed);
+  OBJ_ATTR0.iter().for_each(|va| va.write(no_display));
+
+  let mut obj = ObjAttr::new();
+  obj.set_x(13);
+  obj.set_y(37);
+  obj.set_tile_id(1);
+  OBJ_ATTR_ALL.index(0).write(obj);
+
+  DISPCNT.write(DisplayControl::new().with_show_obj(true));
+
+  loop {
+    VBlankIntrWait();
+    let keys = KEYINPUT.read();
+    if keys.a() {
+      let t = TIMER0_COUNT.read();
+      BACKDROP_COLOR.write(Color(t));
+    }
+  }
+}

examples/hello.rs

@@ -13,7 +13,7 @@ fn panic_handler(info: &core::panic::PanicInfo) -> ! {
 }
 
 #[allow(dead_code)]
-const FOO_: Align4<[u8; 4]> = include_aligned_bytes!("foo.txt");
+const FOO: Align4<[u8; 3]> = include_aligned_bytes!("foo.txt");
 
 #[link_section = ".ewram"]
 static FRAME_KEYS: GbaCell<KeyInput> = GbaCell::new(KeyInput::new());

examples/instruction_inline.rs

@@ -1,6 +1,5 @@
 #![no_std]
 #![no_main]
-#![feature(isa_attribute)]
 
 use gba::prelude::*;
 

src/asm_runtime.rs

@@ -610,6 +610,11 @@ unsafe extern "C" fn __aeabi_uwrite8(value: u64, address: *mut c_void) {
 /// function when possible.
 ///
 /// * **Returns:** the original `dest` pointer.
+///
+/// ## Safety
+/// * `src` must be readable for `byte_count` bytes.
+/// * `dest` must be writable for `byte_count` bytes.
+/// * The `src` and `dest` regions must not overlap.
 #[inline]
 #[no_mangle]
 pub unsafe extern "C" fn memcpy(
@@ -626,6 +631,10 @@ pub unsafe extern "C" fn memcpy(
 /// function when possible.
 ///
 /// * **Returns:** the original `dest` pointer.
+///
+/// ## Safety
+/// * `src` must be readable for `byte_count` bytes.
+/// * `dest` must be writable for `byte_count` bytes.
 #[inline]
 #[no_mangle]
 pub unsafe extern "C" fn memmove(
@@ -644,6 +653,9 @@ pub unsafe extern "C" fn memmove(
 /// it up like might happen in C.
 ///
 /// * **Returns:** the original `dest` pointer.
+///
+/// ## Safety
+/// * `dest` must be writable for `byte_count` bytes.
 #[inline]
 #[no_mangle]
 pub unsafe extern "C" fn memset(

src/bios.rs

@@ -1,4 +1,5 @@
 #![allow(non_snake_case)]
+#![allow(clippy::missing_safety_doc)]
 
 //! The GBA's BIOS provides limited built-in utility functions.
 //!

src/fixed.rs

@@ -262,6 +262,7 @@ macro_rules! impl_signed_fixed_ops {
     }
     impl_trait_op_unit!($t, Neg, neg);
     impl<const B: u32> core::fmt::Debug for Fixed<$t, B> {
+      #[inline]
       fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
         let whole: $t = self.trunc().into_raw() >> B;
         let fract: $t = self.fract().into_raw();
@@ -315,6 +316,7 @@ macro_rules! impl_unsigned_fixed_ops {
       }
     }
     impl<const B: u32> core::fmt::Debug for Fixed<$t, B> {
+      #[inline]
       fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
         let whole: $t = self.trunc().into_raw() >> B;
         let fract: $t = self.fract().into_raw();

src/gba_cell.rs

@@ -64,6 +64,7 @@ impl<T> Debug for GbaCell<T>
 where
   T: GbaCellSafe + Debug,
 {
+  #[inline]
   fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
     <T as Debug>::fmt(&self.read(), f)
   }

src/lib.rs

@@ -1,8 +1,9 @@
 #![no_std]
-#![feature(asm_sym)]
 #![feature(asm_const)]
-#![feature(isa_attribute)]
 #![feature(naked_functions)]
+#![warn(clippy::missing_inline_in_public_items)]
+#![allow(clippy::let_and_return)]
+#![allow(clippy::result_unit_err)]
 //#![warn(missing_docs)]
 
 //! A crate for GBA development.
@@ -72,9 +73,10 @@
 //!
 //! ## Other GBA-related Crates
 //!
-//! This crate provides a largely "unmanaged" interaction with the GBA's
-//! hardware. If you would like an API that use the borrow checker to guide you
-//! more, the [agb](https://docs.rs/agb) crate might be what you want.
+//! This crate provides an API to interact with the GBA that is safe, but with
+//! minimal restrictions on what components can be changed when. If you'd like
+//! an API where the borrow checker provides stronger control over component
+//! access then the [agb](https://docs.rs/agb) crate might be what you want.
 //!
 //! ## Safety
 //!
@@ -114,6 +116,7 @@ impl<const N: usize> Align4<[u8; N]> {
   /// Views these bytes as a slice of `u32`
   /// ## Panics
   /// * If the number of bytes isn't a multiple of 4
+  #[inline]
   pub fn as_u32_slice(&self) -> &[u32] {
     assert!(self.0.len() % 4 == 0);
     // Safety: our struct is aligned to 4, so the pointer will already be
@@ -128,6 +131,7 @@ impl<const N: usize> Align4<[u8; N]> {
   /// Views these bytes as a slice of `u16`
   /// ## Panics
   /// * If the number of bytes isn't a multiple of 2
+  #[inline]
   pub fn as_u16_slice(&self) -> &[u16] {
     assert!(self.0.len() % 2 == 0);
     // Safety: our struct is aligned to 4, so the pointer will already be
@@ -144,7 +148,6 @@ impl<const N: usize> Align4<[u8; N]> {
 #[macro_export]
 macro_rules! include_aligned_bytes {
   ($file:expr $(,)?) => {{
-    let LONG_NAME_THAT_DOES_NOT_CLASH = *include_bytes!($file);
-    Align4(LONG_NAME_THAT_DOES_NOT_CLASH)
+    Align4(*include_bytes!($file))
   }};
 }

src/mgba.rs

@@ -71,6 +71,7 @@ pub struct MgbaBufferedLogger {
   pub message_level: MgbaMessageLevel,
 }
 impl MgbaBufferedLogger {
+  #[inline]
   pub fn try_new(message_level: MgbaMessageLevel) -> Result<Self, ()> {
     if mgba_logging_available() {
       Ok(Self { byte_count: 0, message_level })
@@ -84,6 +85,7 @@ impl MgbaBufferedLogger {
   }
 }
 impl Drop for MgbaBufferedLogger {
+  #[inline]
   fn drop(&mut self) {
     if self.byte_count != 0 {
       self.flush();
@@ -91,6 +93,7 @@ impl Drop for MgbaBufferedLogger {
   }
 }
 impl core::fmt::Write for MgbaBufferedLogger {
+  #[inline]
   fn write_str(&mut self, s: &str) -> core::fmt::Result {
     for b in s.as_bytes().iter().copied() {
       if b == b'\n' {

src/mmio.rs

@@ -35,9 +35,10 @@ use crate::{
   },
   dma::DmaControl,
   sound::{
-    SweepControl, TonePattern, ToneFrequency, WaveBank, WaveLenVolume, WaveFrequency, NoiseLenEnvelope, NoiseFrequency, LeftRightVolume, SoundMix, SoundEnable, SoundBias
+    SweepControl, TonePattern, ToneFrequency, WaveBank, WaveLenVolume, WaveFrequency,
+    NoiseLenEnvelope, NoiseFrequency, LeftRightVolume, SoundMix, SoundEnable, SoundBias
   },
-  timers::TimerControl, keys::{KeyInput, KeyControl}, mgba::MgbaMessageLevel, fixed::{i16fx8, i32fx8},
+  timers::TimerControl, keys::{KeyInput, KeyControl}, mgba::MgbaMessageLevel, fixed::{i16fx8, i32fx8}, prelude::ObjAttr,
 };
 
 // Note(Lokathor): This macro lets us stick each address at the start of the
@@ -214,14 +215,14 @@ def_mmio!(0x0500_0200 = OBJ_PALETTE: VolBlock<Color, Safe, Safe, 256>; "Object t
 
 // Video RAM (VRAM)
 
-/// The VRAM offset per screenblock index.
+/// The VRAM byte offset per screenblock index.
 /// 
 /// This is the same for all background types and sizes.
 pub const SCREENBLOCK_INDEX_OFFSET: usize = 2 * 1_024;
 
 /// The size of the background tile region of VRAM.
 /// 
-/// Background tile index use can cross between charblocks, but not past the end
+/// Background tile index use will work between charblocks, but not past the end
 /// of BG tile memory into OBJ tile memory.
 pub const BG_TILE_REGION_SIZE: usize = 64 * 1_024;
 
@@ -475,6 +476,8 @@ def_mmio!(0x0700_0000 = OBJ_ATTR0: VolSeries<ObjAttr0, Safe, Safe, 128, {size_of
 def_mmio!(0x0700_0002 = OBJ_ATTR1: VolSeries<ObjAttr1, Safe, Safe, 128, {size_of::<[u16;4]>()}>; "Object attributes 1.");
 def_mmio!(0x0700_0004 = OBJ_ATTR2: VolSeries<ObjAttr2, Safe, Safe, 128, {size_of::<[u16;4]>()}>; "Object attributes 2.");
 
+def_mmio!(0x0700_0000 = OBJ_ATTR_ALL: VolSeries<ObjAttr, Safe, Safe, 128, {size_of::<[u16;4]>()}>; "Object attributes (all in one).");
+
 def_mmio!(0x0700_0006 = AFFINE_PARAM_A: VolSeries<i16fx8, Safe, Safe, 32, {size_of::<[u16;16]>()}>; "Affine parameters A.");
 def_mmio!(0x0700_000E = AFFINE_PARAM_B: VolSeries<i16fx8, Safe, Safe, 32, {size_of::<[u16;16]>()}>; "Affine parameters B.");
 def_mmio!(0x0700_0016 = AFFINE_PARAM_C: VolSeries<i16fx8, Safe, Safe, 32, {size_of::<[u16;16]>()}>; "Affine parameters C.");

src/video/mod.rs

@@ -107,7 +107,17 @@ use crate::prelude::*;
 #[derive(Debug, Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[repr(transparent)]
 pub struct Color(pub u16);
+#[allow(clippy::unusual_byte_groupings)]
 impl Color {
+  pub const BLACK: Color = Color(0b0_00000_00000_00000);
+  pub const RED: Color = Color(0b0_00000_00000_11111);
+  pub const GREEN: Color = Color(0b0_00000_11111_00000);
+  pub const YELLOW: Color = Color(0b0_00000_11111_11111);
+  pub const BLUE: Color = Color(0b0_11111_00000_00000);
+  pub const MAGENTA: Color = Color(0b0_11111_00000_11111);
+  pub const CYAN: Color = Color(0b0_11111_11111_00000);
+  pub const WHITE: Color = Color(0b0_11111_11111_11111);
+
   pub_const_fn_new_zeroed!();
   u16_int_field!(0 - 4, red, with_red);
   u16_int_field!(5 - 9, green, with_green);
@@ -358,3 +368,22 @@ impl ObjAttr2 {
   u16_int_field!(10 - 11, priority, with_priority);
   u16_int_field!(12 - 15, palbank, with_palbank);
 }
+
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[repr(C)]
+pub struct ObjAttr(pub ObjAttr0, pub ObjAttr1, pub ObjAttr2);
+impl ObjAttr {
+  #[inline]
+  pub const fn new() -> Self {
+    Self(ObjAttr0(0), ObjAttr1(0), ObjAttr2(0))
+  }
+  pub fn set_x(&mut self, x: u16) {
+    self.1 = self.1.with_x(x);
+  }
+  pub fn set_y(&mut self, y: u16) {
+    self.0 = self.0.with_y(y);
+  }
+  pub fn set_tile_id(&mut self, id: u16) {
+    self.2 = self.2.with_tile_id(id);
+  }
+}