mirror of
https://github.com/italicsjenga/gba.git
synced 2024-12-24 11:11:31 +11:00
96 lines
2.3 KiB
Rust
96 lines
2.3 KiB
Rust
#![feature(start)]
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#![no_std]
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#[cfg(not(test))]
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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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DISPCNT.write_volatile(MODE3 | BG2);
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mode3_pixel(120, 80, rgb16(31, 0, 0));
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mode3_pixel(136, 80, rgb16(0, 31, 0));
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mode3_pixel(120, 96, rgb16(0, 0, 31));
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loop {}
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}
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}
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pub const DISPCNT: *mut u16 = 0x04000000 as *mut u16;
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pub const MODE3: u16 = 3;
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pub const BG2: u16 = 0b100_0000_0000;
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pub const VRAM: usize = 0x06000000;
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pub const SCREEN_WIDTH: isize = 240;
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pub const fn rgb16(red: u16, green: u16, blue: u16) -> u16 {
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blue << 10 | green << 5 | red
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}
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pub unsafe fn mode3_pixel(col: isize, row: isize, color: u16) {
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(VRAM as *mut u16).offset(col + row * SCREEN_WIDTH).write_volatile(color);
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}
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pub const KEYINPUT: *mut u16 = 0x400_0130 as *mut u16;
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/// A newtype over the key input state of the GBA.
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#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
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#[repr(transparent)]
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pub struct KeyInputSetting(u16);
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/// A "tribool" value helps us interpret the arrow pad.
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#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
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#[repr(i32)]
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pub enum TriBool {
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Minus = -1,
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Neutral = 0,
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Plus = 1,
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}
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pub fn read_key_input() -> KeyInputSetting {
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unsafe { KeyInputSetting(KEYINPUT.volatile_read() ^ 0b1111_1111_1111_1111) }
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}
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pub const KEY_A: u16 = 1 << 0;
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pub const KEY_B: u16 = 1 << 1;
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pub const KEY_SELECT: u16 = 1 << 2;
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pub const KEY_START: u16 = 1 << 3;
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pub const KEY_RIGHT: u16 = 1 << 4;
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pub const KEY_LEFT: u16 = 1 << 5;
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pub const KEY_UP: u16 = 1 << 6;
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pub const KEY_DOWN: u16 = 1 << 7;
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pub const KEY_R: u16 = 1 << 8;
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pub const KEY_L: u16 = 1 << 9;
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impl KeyInputSetting {
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pub fn contains(&self, key: u16) -> bool {
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(self.0 & key) != 0
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}
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pub fn difference(&self, other: KeyInputSetting) -> KeyInputSetting {
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KeyInputSetting(self.0 ^ other.0)
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}
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pub fn column_direction(&self) -> TriBool {
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if self.contains(KEY_RIGHT) {
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TriBool::Plus
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} else if self.contains(KEY_LEFT) {
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TriBool::Minus
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} else {
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TriBool::Neutral
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}
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}
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pub fn row_direction(&self) -> TriBool {
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if self.contains(KEY_DOWN) {
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TriBool::Plus
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} else if self.contains(KEY_UP) {
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TriBool::Minus
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} else {
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TriBool::Neutral
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}
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}
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}
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