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Author SHA1 Message Date
e48e8881e7 update readme 2021-12-26 10:53:39 -05:00
758d17675e More cgb-acid2 progress 2021-12-26 10:49:32 -05:00
eb0f61aebd CPU Registers for CGB mode 2021-12-26 08:58:09 -05:00
5 changed files with 54 additions and 17 deletions

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@ -29,10 +29,9 @@ Any help or suggestion is welcome!
- [ ] MBC7 - [ ] MBC7
- [ ] HuC1 - [ ] HuC1
- [x] Save files - [x] Save files
- [ ] Web Assembly support (because this is a Rust project and it has to support Web Assembly)
- [ ] Gameboy boot ROM (not important for now) - [ ] Gameboy boot ROM (not important for now)
- [ ] Gameboy Color compatibility - [ ] Gameboy Color compatibility (WIP)
- [ ] Sound - [ ] Sound (WIP)
- [ ] Many code refactors and optimizations - [ ] Many code refactors and optimizations
# Resources # Resources

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@ -36,6 +36,7 @@ pub struct Bus {
pub timer: Timer, pub timer: Timer,
pub sound: Sound, pub sound: Sound,
pub interrupts: Interrupts, pub interrupts: Interrupts,
pub cgb_mode: bool,
} }
impl Bus { impl Bus {
@ -67,6 +68,7 @@ impl Bus {
timer: Timer::new(), timer: Timer::new(),
sound: Sound::new(), sound: Sound::new(),
interrupts: Interrupts::new(), interrupts: Interrupts::new(),
cgb_mode,
}; };
// Hardware registers after the bootrom // Hardware registers after the bootrom

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@ -87,6 +87,21 @@ impl Registers {
} }
} }
pub fn new_cgb() -> Self {
Self {
a: 0x11,
f: 0x00,
b: 0x00,
c: 0x00,
d: 0xFF,
e: 0x56,
h: 0x00,
l: 0x0D,
sp: 0xFFFE,
pc: 0x0100,
}
}
pub fn get(&self, register: Register) -> u16 { pub fn get(&self, register: Register) -> u16 {
match register { match register {
Register::A => self.a as u16, Register::A => self.a as u16,
@ -818,9 +833,12 @@ pub struct CPU {
} }
impl CPU { impl CPU {
pub fn new() -> Self { pub fn new(cgb_mode: bool) -> Self {
Self { Self {
registers: Registers::new(), registers: match cgb_mode {
true => Registers::new_cgb(),
false => Registers::new(),
},
cycles: Cycles(0), cycles: Cycles(0),
last_op_cycles: Cycles(0), last_op_cycles: Cycles(0),
exec_calls_count: 0, exec_calls_count: 0,

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@ -16,9 +16,11 @@ pub struct Emulator {
impl Emulator { impl Emulator {
pub fn new() -> Self { pub fn new() -> Self {
let bus = Bus::new();
let cgb_mode = bus.cgb_mode;
Self { Self {
bus: Bus::new(), bus,
cpu: CPU::new(), cpu: CPU::new(cgb_mode),
} }
} }

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@ -71,9 +71,9 @@ impl ColorPalette {
} }
fn extract_rgb(color: u16) -> RGBA { fn extract_rgb(color: u16) -> RGBA {
let red = (color & 0b1111).to_be_bytes()[1]; let red = (color & 0b11111).to_be_bytes()[1];
let green = ((color >> 4) & 0b1111).to_be_bytes()[1]; let green = ((color >> 5) & 0b11111).to_be_bytes()[1];
let blue = ((color >> 8) & 0b1111).to_be_bytes()[1]; let blue = ((color >> 10) & 0b11111).to_be_bytes()[1];
RGBA((red << 3) | (red >> 2), (green << 3) | (green >> 2), (blue << 3) | (blue >> 2), 0) RGBA((red << 3) | (red >> 2), (green << 3) | (green >> 2), (blue << 3) | (blue >> 2), 0)
} }
@ -195,7 +195,7 @@ impl Sprite {
self.x self.x
} }
pub fn get_pixel(&mut self, lcd_x: u8, lcd_y: u8, vram: &[u8], last_bg_index: u8, lcd_control: u8, is_cgb: bool) -> Option<(Pixel, bool, u8)> { pub fn get_pixel(&mut self, lcd_x: u8, lcd_y: u8, vram: &[u8], last_bg_index: u8, last_bg_priority: bool, lcd_control: u8, is_cgb: bool) -> Option<(Pixel, bool, u8)> {
if !LCDControl::ObjectEnable.get(lcd_control) { if !LCDControl::ObjectEnable.get(lcd_control) {
return None; return None;
} }
@ -204,6 +204,10 @@ impl Sprite {
return None; return None;
} }
if is_cgb && LCDControl::BackgroundPriority.get(lcd_control) && last_bg_priority {
return None;
}
if self.over_bg && (last_bg_index & 0b11) != 0 { if self.over_bg && (last_bg_index & 0b11) != 0 {
return None; return None;
} }
@ -244,8 +248,8 @@ impl Sprite {
let addr = 0x8000 + (tile_number as u16 * 16) + tile_line as u16; let addr = 0x8000 + (tile_number as u16 * 16) + tile_line as u16;
let vram_start = 0x8000; let vram_start = 0x8000;
let tile_byte_1 = vram[(addr - vram_start) as usize]; let tile_byte_1 = vram[(0x2000 * self.vram_bank as usize) + (addr - vram_start) as usize];
let tile_byte_2 = vram[(addr - vram_start + 1) as usize]; let tile_byte_2 = vram[(0x2000 * self.vram_bank as usize) + (addr - vram_start + 1) as usize];
let bit_pixels_array = PPU::get_byte_pixels(tile_byte_1, tile_byte_2); let bit_pixels_array = PPU::get_byte_pixels(tile_byte_1, tile_byte_2);
self.bit_pixels = Some(bit_pixels_array); self.bit_pixels = Some(bit_pixels_array);
@ -274,6 +278,7 @@ pub struct PPU {
sprite_buffer: Vec<Sprite>, sprite_buffer: Vec<Sprite>,
window_y_counter: u8, window_y_counter: u8,
last_bg_index: u8, last_bg_index: u8,
last_bg_priority: bool,
bg_palette: u8, bg_palette: u8,
lcd_control: u8, lcd_control: u8,
current_background_pixels: Option<([u8; 8], u8)>, current_background_pixels: Option<([u8; 8], u8)>,
@ -306,6 +311,7 @@ impl PPU {
sprite_buffer: Vec::new(), sprite_buffer: Vec::new(),
window_y_counter: 0, window_y_counter: 0,
last_bg_index: 0, last_bg_index: 0,
last_bg_priority: false,
bg_palette: 0, bg_palette: 0,
lcd_control: 0, lcd_control: 0,
current_background_pixels: None, current_background_pixels: None,
@ -482,7 +488,7 @@ impl PPU {
self.lcd_y = self.lcd_y.wrapping_add(1); self.lcd_y = self.lcd_y.wrapping_add(1);
self.lcd_x = 0; self.lcd_x = 0;
if self.window_drawn { if self.window_drawn {
self.window_y_counter += 1; self.window_y_counter = self.window_y_counter.saturating_add(1);
} }
// Frame completed // Frame completed
@ -598,7 +604,7 @@ impl PPU {
fn find_sprite_pixel(&mut self) -> Option<(Pixel, bool, u8)> { fn find_sprite_pixel(&mut self) -> Option<(Pixel, bool, u8)> {
let lcd_y = self.lcd_y; let lcd_y = self.lcd_y;
for sprite in &mut self.sprite_buffer { for sprite in &mut self.sprite_buffer {
if let Some(pixel) = sprite.get_pixel(self.lcd_x, lcd_y, &self.vram, self.last_bg_index, self.lcd_control, self.cgb_mode) { if let Some(pixel) = sprite.get_pixel(self.lcd_x, lcd_y, &self.vram, self.last_bg_index, self.last_bg_priority, self.lcd_control, self.cgb_mode) {
return Some(pixel); return Some(pixel);
} }
} }
@ -693,9 +699,16 @@ impl PPU {
} }
fn get_window_pixel(&mut self) -> Option<(Pixel, u8)> { fn get_window_pixel(&mut self) -> Option<(Pixel, u8)> {
if !self.window_enable { if !self.window_enable {
self.last_bg_index = 0b00;
return None; return None;
} }
if !self.cgb_mode {
if !self.background_priority || !self.window_enable {
self.last_bg_index = 0b00;
return None;
}
}
let lcd_y = self.lcd_y; let lcd_y = self.lcd_y;
let lcd_x = self.lcd_x; let lcd_x = self.lcd_x;
@ -732,6 +745,7 @@ impl PPU {
let (tile_byte_1, tile_byte_2, info) = self.get_tile_bytes(x, y, tilemap_area, default_mode); let (tile_byte_1, tile_byte_2, info) = self.get_tile_bytes(x, y, tilemap_area, default_mode);
let bit_pixels_array = PPU::get_byte_pixels(tile_byte_1, tile_byte_2); let bit_pixels_array = PPU::get_byte_pixels(tile_byte_1, tile_byte_2);
self.current_window_pixels = Some((bit_pixels_array, info.palette_number)); self.current_window_pixels = Some((bit_pixels_array, info.palette_number));
self.last_bg_priority = info.bg_to_oam_priority;
(bit_pixels_array, info.palette_number) (bit_pixels_array, info.palette_number)
}, },
@ -746,7 +760,8 @@ impl PPU {
} }
fn get_background_pixel(&mut self) -> Option<(Pixel, u8)> { fn get_background_pixel(&mut self) -> Option<(Pixel, u8)> {
if !self.background_priority { if !self.cgb_mode && !self.background_priority {
self.last_bg_index = 0b00;
return None; return None;
} }
let lcd_y = self.lcd_y; let lcd_y = self.lcd_y;
@ -772,6 +787,7 @@ impl PPU {
let (tile_byte_1, tile_byte_2, info) = self.get_tile_bytes(x, y, tilemap_area, default_mode); let (tile_byte_1, tile_byte_2, info) = self.get_tile_bytes(x, y, tilemap_area, default_mode);
let bit_pixels_array = PPU::get_byte_pixels(tile_byte_1, tile_byte_2); let bit_pixels_array = PPU::get_byte_pixels(tile_byte_1, tile_byte_2);
self.current_background_pixels = Some((bit_pixels_array, info.palette_number)); self.current_background_pixels = Some((bit_pixels_array, info.palette_number));
self.last_bg_priority = info.bg_to_oam_priority;
(bit_pixels_array, info.palette_number) (bit_pixels_array, info.palette_number)
}, },