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Refactor PPU interrupt requests and fix Scroll X

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This commit is contained in:
Franco Colmenarez 2021-11-03 22:24:31 -05:00
parent 60fd55abca
commit c5ff92c0ab
5 changed files with 58 additions and 43 deletions
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16
src/bus.rs
View File

@ -59,7 +59,7 @@ pub struct Bus {
impl Bus {
pub fn new() -> Self {
let game_rom = match ROM::load_file("ignore/tetris.gb".to_string()) {
let game_rom = match ROM::load_file("ignore/m3_scy_change.gb".to_string()) {
// let game_rom = match ROM::load_file("roms/cpu_instrs.gb".to_string()) {
// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/01-special.gb".to_string()) {
// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/02-interrupts.gb".to_string()) {
@ -111,9 +111,6 @@ impl Bus {
if BANK_ZERO.in_range(address) || BANK_SWITCHABLE.in_range(address) {
return self.game_rom.read(address);
}
if address == JOYPAD_ADDRESS {
println!("{:08b}", self.data[address as usize]);
}
self.data[address as usize]
}
@ -142,11 +139,14 @@ impl Bus {
} else if address == LCD_CONTROL_ADDRESS && get_bit(data, BitIndex::I7) {
self.data[address as usize] = data;
self.data[LCD_Y_ADDRESS as usize] = 0x00;
} else if address == JOYPAD_ADDRESS {
let byte = self.data[JOYPAD_ADDRESS as usize];
self.data[JOYPAD_ADDRESS as usize] = (data & 0b11110000) | (byte & 0b00001111);
} else if address == LCD_Y_ADDRESS {
println!("Write to LCD_Y not allowed");
// println!("Write to LCD_Y not allowed");
} else if address == LCD_STATUS_ADDRESS {
let byte = self.data[address as usize];
self.data[address as usize] = (data & 0b11111000) | (byte & 0b00000111);
} else if address == JOYPAD_ADDRESS {
let byte = self.data[address as usize];
self.data[address as usize] = (data & 0b11110000) | (byte & 0b00001111);
} else {
self.data[address as usize] = data;
}

1
src/emulator.rs
View File

@ -96,7 +96,6 @@ impl Emulator {
self.joypad.release(Button::Select);
}
if change {
self.joypad.update(&mut self.bus);
self.bus.set_interrupt_flag(Interrupt::Joypad, true);
}
}

5
src/joypad.rs
View File

@ -68,7 +68,7 @@ impl Joypad {
};
}
pub fn update(&self, bus: &mut Bus) {
pub fn read(&self, bus: &mut Bus) -> u8 {
let byte = bus.read(JOYPAD_ADDRESS);
let direction = !get_bit(byte, BitIndex::I4);
let action = !get_bit(byte, BitIndex::I5);
@ -83,7 +83,6 @@ impl Joypad {
) | (
(!((direction && self.right) || (action && self.a)) as u8)
);
println!("New joypad write: {:08b}", data);
bus.force_write(JOYPAD_ADDRESS, data);
return data;
}
}

77
src/ppu.rs
View File

@ -91,6 +91,7 @@ pub enum LCDStatus {
}
pub struct PPU {
prev_state: bool,
cycles: Cycles,
rgba_frame: [[u8; 4]; FRAME_BUFFER_LENGTH as usize],
}
@ -103,6 +104,7 @@ enum TileNumber {
impl PPU {
pub fn new() -> Self {
Self {
prev_state: false,
cycles: Cycles(0),
rgba_frame: [[0xFF, 0xFF, 0xFF, 0]; FRAME_BUFFER_LENGTH as usize],
}
@ -134,9 +136,7 @@ impl PPU {
if self.cycles.0 == 0 {
// Mode 2 OAM scan
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::SearchingOAM), true);
if PPU::get_lcd_status(bus, LCDStatus::Mode2OAMInterrupt) {
PPU::request_interrupt(bus, Interrupt::LCDSTAT);
}
self.stat_interrupt(bus);
} else if self.cycles.0 == 80 + 1 {
// Mode 3 drawing pixel line. This could also last 289 cycles
self.draw_line(bus, frame_buffer);
@ -144,16 +144,13 @@ impl PPU {
} else if self.cycles.0 == 80 + 172 + 1 {
// Mode 0 Horizontal blank. This could last 87 or 204 cycles depending on the mode 3
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::HBlank), true);
if PPU::get_lcd_status(bus, LCDStatus::Mode0HBlankInterrupt) {
PPU::request_interrupt(bus, Interrupt::LCDSTAT);
}
self.stat_interrupt(bus);
}
} else if PPU::get_lcd_y(bus) == 144 && self.cycles.0 == 0 {
// Mode 1 Vertical blank
bus.set_interrupt_flag(Interrupt::VBlank, true);
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::VBlank), true);
if PPU::get_lcd_status(bus, LCDStatus::Mode1VBlankInterrupt) {
PPU::request_interrupt(bus, Interrupt::VBlank);
}
self.stat_interrupt(bus);
}
self.increment_cycles(Cycles(1));
@ -167,21 +164,28 @@ impl PPU {
if PPU::get_lcd_y(bus) > 153 {
PPU::set_lcd_y(bus, 0);
}
PPU::check_lyc(bus);
self.check_lyc(bus);
}
}
fn check_lyc(bus: &mut Bus) {
fn stat_interrupt(&mut self, bus: &mut Bus) {
let state = self.prev_state;
self.prev_state = (
(PPU::get_lcd_status(bus, LCDStatus::Mode2OAMInterrupt) && PPU::get_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::SearchingOAM))) ||
(PPU::get_lcd_status(bus, LCDStatus::Mode0HBlankInterrupt) && PPU::get_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::HBlank))) ||
(PPU::get_lcd_status(bus, LCDStatus::Mode1VBlankInterrupt) && PPU::get_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::VBlank)))
);
if self.prev_state && !state {
bus.set_interrupt_flag(Interrupt::LCDSTAT, true);
}
}
fn check_lyc(&mut self, bus: &mut Bus) {
let lyc_compare = PPU::get_lcd_y(bus) == bus.read(LCD_Y_COMPARE_ADDRESS);
if PPU::get_lcd_status(bus, LCDStatus::LYCInterrupt) && lyc_compare {
PPU::set_lcd_status(bus, LCDStatus::LYCFlag, lyc_compare);
PPU::request_interrupt(bus, Interrupt::LCDSTAT);
}
}
fn request_interrupt(bus: &mut Bus, interrupt: Interrupt) {
if PPU::get_lcd_control(bus, LCDControl::LCDEnable) {
bus.set_interrupt_flag(interrupt, true);
PPU::set_lcd_status(bus, LCDStatus::LYCFlag, lyc_compare);
if lyc_compare && PPU::get_lcd_status(bus, LCDStatus::LYCInterrupt) {
bus.set_interrupt_flag(Interrupt::LCDSTAT, true);
self.prev_state = true;
}
}
@ -216,7 +220,7 @@ impl PPU {
fn set_lcd_control(bus: &mut Bus, control: LCDControl, val: bool) {
let mut byte = bus.read(LCD_CONTROL_ADDRESS);
bus.write(LCD_CONTROL_ADDRESS, control.set(byte, val));
bus.force_write(LCD_CONTROL_ADDRESS, control.set(byte, val));
}
pub fn get_lcd_status(bus: &Bus, status: LCDStatus) -> bool {
@ -251,7 +255,7 @@ impl PPU {
LCDStatusModeFlag::TransferringToLCD => (byte & 0b11111100) | 3,
},
};
bus.write(LCD_STATUS_ADDRESS, byte);
bus.force_write(LCD_STATUS_ADDRESS, byte);
}
fn get_tile_bytes(x: u8, y: u8, tile_number_type: TileNumber, default_method: bool, bus: &Bus) -> (u8, u8) {
@ -277,15 +281,15 @@ impl PPU {
fn get_window_pixel(lcd_x: u8, bus: &Bus) -> Option<Pixel> {
let lcd_y = PPU::get_lcd_y(bus);
let window_x = (PPU::get_window_x(bus) as i8 - 7) as u8;
let window_x = PPU::get_window_x(bus);
let window_y = PPU::get_window_y(bus);
if !PPU::get_lcd_control(bus, LCDControl::WindowEnable) || window_x != lcd_x || window_y != lcd_y {
if !PPU::get_lcd_control(bus, LCDControl::WindowEnable) || lcd_x < (window_x.saturating_sub(7)) || window_y != lcd_y {
return None;
}
let x = lcd_x - window_x;
let y = lcd_y - window_x;
let x = lcd_x.wrapping_sub(window_x.saturating_sub(7));
let y = lcd_y.wrapping_sub(window_y);
let default_mode = PPU::get_lcd_control(bus, LCDControl::TileAddressMode);
let tilemap_area = match PPU::get_lcd_control(bus, LCDControl::WindowTileMapAddress) {
@ -320,23 +324,36 @@ impl PPU {
let bg_pixels = PPU::get_byte_pixels(tile_byte_1, tile_byte_2, palette);
for pixel in bg_pixels {
let idx = (lcd_x as usize + (lcd_y as usize * LCD_WIDTH as usize)) * 4;
let pixel = bg_pixels[x.rem_euclid(8) as usize];
let rgba = PPU::get_rgba(pixel);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
if let Some(window_pixel) = PPU::get_window_pixel(lcd_x, bus) {
let rgba = PPU::get_rgba(pixel);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
}
lcd_x += 1;
/* for pixel in bg_pixels {
let idx = (lcd_x as usize + (lcd_y as usize * LCD_WIDTH as usize)) * 4;
let rgba = PPU::get_rgba(pixel);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
frame_buffer[idx + 3] = rgba[3];
if let Some(window_pixel) = PPU::get_window_pixel(lcd_x, bus) {
let rgba = PPU::get_rgba(pixel);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
frame_buffer[idx + 3] = rgba[3];
}
lcd_x += 1;
}
} */
}
}

2
src/render.rs
View File

@ -67,7 +67,7 @@ pub fn start_eventloop() {
emulator.run(Cycles(70224), pixels.get_frame());
// emulator.draw(pixels.get_frame());
// thread::sleep(time::Duration::from_millis(14));
// thread::sleep(time::Duration::from_millis(1000));
window.request_redraw();
},
Event::RedrawRequested(_) => {