mirror of
https://github.com/italicsjenga/gba.git
synced 2024-10-17 13:21:31 +11:00
97 lines
2.5 KiB
Rust
97 lines
2.5 KiB
Rust
#![no_std]
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#![feature(start)]
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#![feature(underscore_const_names)]
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#[macro_export]
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macro_rules! newtype {
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($(#[$attr:meta])* $new_name:ident, $old_name:ident) => {
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$(#[$attr])*
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#[repr(transparent)]
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pub struct $new_name($old_name);
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};
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}
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#[macro_export]
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macro_rules! const_assert {
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($condition:expr) => {
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#[deny(const_err)]
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#[allow(dead_code)]
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const _: usize = 0 - !$condition as usize;
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};
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}
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/// Constructs an RGB value with a `const_assert!` that the input is in range.
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#[macro_export]
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macro_rules! const_rgb {
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($r:expr, $g:expr, $b:expr) => {{
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const_assert!($r <= 31);
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const_assert!($g <= 31);
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const_assert!($b <= 31);
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Color::new($r, $g, $b)
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}};
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}
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// TODO: kill this
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#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
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#[repr(transparent)]
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pub struct VolatilePtr<T>(pub *mut T);
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impl<T> VolatilePtr<T> {
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pub unsafe fn read(&self) -> T {
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core::ptr::read_volatile(self.0)
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}
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pub unsafe fn write(&self, data: T) {
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core::ptr::write_volatile(self.0, data);
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}
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pub unsafe fn offset(self, count: isize) -> Self {
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VolatilePtr(self.0.wrapping_offset(count))
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}
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}
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newtype! {
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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Color, u16
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}
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impl Color {
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/// Combines the Red, Blue, and Green provided into a single color value.
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pub const fn new(red: u16, green: u16, blue: u16) -> Color {
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Color(blue << 10 | green << 5 | red)
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}
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}
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newtype! {
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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DisplayControlSetting, u16
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}
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pub const DISPLAY_CONTROL: VolatilePtr<DisplayControlSetting> = VolatilePtr(0x0400_0000 as *mut DisplayControlSetting);
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pub const JUST_MODE3: DisplayControlSetting = DisplayControlSetting(3);
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pub const JUST_BG2: DisplayControlSetting = DisplayControlSetting(0b100_0000_0000);
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pub const JUST_MODE3_AND_BG2: DisplayControlSetting = DisplayControlSetting(JUST_MODE3.0 | JUST_BG2.0);
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pub struct Mode3;
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impl Mode3 {
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const SCREEN_WIDTH: isize = 240;
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const PIXELS: VolatilePtr<Color> = VolatilePtr(0x600_0000 as *mut Color);
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pub unsafe fn draw_pixel_unchecked(col: isize, row: isize, color: Color) {
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Self::PIXELS.offset(col + row * Self::SCREEN_WIDTH).write(color);
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}
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}
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#[panic_handler]
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fn panic(_info: &core::panic::PanicInfo) -> ! {
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loop {}
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}
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#[start]
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fn main(_argc: isize, _argv: *const *const u8) -> isize {
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unsafe {
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DISPLAY_CONTROL.write(JUST_MODE3_AND_BG2);
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Mode3::draw_pixel_unchecked(120, 80, const_rgb!(31, 0, 0));
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Mode3::draw_pixel_unchecked(136, 80, const_rgb!(0, 31, 0));
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Mode3::draw_pixel_unchecked(120, 96, const_rgb!(0, 0, 31));
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loop {}
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}
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}
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