diff --git a/examples/sdl/src/main.rs b/examples/sdl/src/main.rs
index f72bf2aa808ef50cc397c68fd013715008f6cd8a..2e236739c81b0488159c8132e66c0d5408420ba3 100644
--- a/examples/sdl/src/main.rs
+++ b/examples/sdl/src/main.rs
@@ -84,7 +84,8 @@ fn main() {
let mut game_boy = GameBoy::new();
game_boy.load_boot_default();
- game_boy.load_rom_file("../../res/roms.prop/tetris.gb");
+ //game_boy.load_rom_file("../../res/roms.prop/tetris.gb");
+ game_boy.load_rom_file("../../res/roms.prop/dr_mario.gb");
//game_boy.load_rom_file("../../res/roms.prop/alleyway.gb");
//game_boy.load_rom_file("../../res/roms/firstwhite.gb");
diff --git a/src/cpu.rs b/src/cpu.rs
index 34d659d3669bb8a8de51ca49f4ff76267d6c3742..9d538684346b700d201f9e220673d215ea31d877 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -4,7 +4,8 @@ use crate::{
inst::{EXTENDED, INSTRUCTIONS},
mmu::Mmu,
pad::Pad,
- ppu::Ppu, timer::Timer,
+ ppu::Ppu,
+ timer::Timer,
};
pub const PREFIX: u8 = 0xcb;
@@ -129,6 +130,27 @@ impl Cpu {
return 16;
}
+
+ // @todo aggregate the handling of these interrupts
+ if (self.mmu.ie & 0x04 == 0x04) && self.mmu.timer().int_tima() {
+ println!("Going to run Timer interrupt handler (0x50)");
+
+ self.disable_int();
+ self.push_word(pc);
+ self.pc = 0x50;
+
+ // acknowledges that the timer interrupt has been
+ // properly handled
+ self.mmu.timer().ack_tima();
+
+ // in case the CPU is currently halted waiting
+ // for an interrupt, releases it
+ if self.halted {
+ self.halted = false;
+ }
+
+ return 16;
+ }
}
// in case the CPU is currently in the halted state
@@ -191,7 +213,7 @@ impl Cpu {
pub fn pad(&mut self) -> &mut Pad {
self.mmu().pad()
}
-
+
#[inline(always)]
pub fn timer(&mut self) -> &mut Timer {
self.mmu().timer()
diff --git a/src/data.rs b/src/data.rs
index c9330da6e7c417932c73e6ade7f54d794db89d5f..c77a3e8e5cc6a85a32c0a09832a9d8e89e14cd2e 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -9,8 +9,6 @@ pub enum BootRom {
MgbBootix,
}
-/// Static data corresponding to the DMG boot ROM
-/// allows freely using the emulator without external dependency.
pub const DMG_BOOT: [u8; 256] = [
49, 254, 255, 175, 33, 255, 159, 50, 203, 124, 32, 251, 33, 38, 255, 14, 17, 62, 128, 50, 226,
12, 62, 243, 226, 50, 62, 119, 119, 62, 252, 224, 71, 17, 4, 1, 33, 16, 128, 26, 205, 149, 0,
diff --git a/src/gb.rs b/src/gb.rs
index f9a12c84f9cd375222890984bb1b1a20352cf5f3..acfd5d9825dea000a104bef7fed1ce42213fd263 100644
--- a/src/gb.rs
+++ b/src/gb.rs
@@ -4,7 +4,8 @@ use crate::{
mmu::Mmu,
pad::{Pad, PadKey},
ppu::{Ppu, Tile, FRAME_BUFFER_SIZE},
- util::read_file, timer::Timer,
+ timer::Timer,
+ util::read_file,
};
#[cfg(feature = "wasm")]
@@ -51,6 +52,7 @@ impl GameBoy {
pub fn clock(&mut self) -> u8 {
let cycles = self.cpu_clock();
self.ppu_clock(cycles);
+ self.timer_clock(cycles);
cycles
}
@@ -62,6 +64,10 @@ impl GameBoy {
self.ppu().clock(cycles)
}
+ pub fn timer_clock(&mut self, cycles: u8) {
+ self.timer().clock(cycles)
+ }
+
pub fn load_rom(&mut self, data: &[u8]) {
self.cpu.mmu().write_rom(0x0000, data);
}
diff --git a/src/mmu.rs b/src/mmu.rs
index ed98c3ec0efc4dec3e39c25c5d9c8d47efb0b727..e3dae1ddcfd9fe68afa9179e48b6ca229dcc045e 100644
--- a/src/mmu.rs
+++ b/src/mmu.rs
@@ -96,28 +96,30 @@ impl Mmu {
0x000 | 0x100 | 0x200 | 0x300 | 0x400 | 0x500 | 0x600 | 0x700 | 0x800 | 0x900
| 0xa00 | 0xb00 | 0xc00 | 0xd00 => self.ram[(addr & 0x1fff) as usize],
0xe00 => self.ppu.oam[(addr & 0x009f) as usize],
- 0xf00 => {
- if addr == 0xffff {
- self.ie
- } else if addr >= 0xff80 {
- self.ppu.hram[(addr & 0x007f) as usize]
- } else {
- match addr & 0x00f0 {
- 0x00 => match addr & 0x00ff {
- 0x00 => self.pad.read(addr),
- _ => {
- println!("Reading from unknown IO control 0x{:04x}", addr);
- 0x00
- }
- },
- 0x40 | 0x50 | 0x60 | 0x70 => self.ppu.read(addr),
+ 0xf00 => match addr & 0x00ff {
+ 0x0f => {
+ let value = if self.ppu.int_vblank() { 0x01 } else { 0x00 }
+ | if self.timer.int_tima() { 0x04 } else { 0x00 };
+ value
+ }
+ 0x80..=0xfe => self.ppu.hram[(addr & 0x007f) as usize],
+ 0xff => self.ie,
+ _ => match addr & 0x00f0 {
+ 0x00 => match addr & 0x00ff {
+ 0x00 => self.pad.read(addr),
+ 0x04..=0x07 => self.timer.read(addr),
_ => {
println!("Reading from unknown IO control 0x{:04x}", addr);
0x00
}
+ },
+ 0x40 | 0x50 | 0x60 | 0x70 => self.ppu.read(addr),
+ _ => {
+ println!("Reading from unknown IO control 0x{:04x}", addr);
+ 0x00
}
- }
- }
+ },
+ },
addr => panic!("Reading from unknown location 0x{:04x}", addr),
},
addr => panic!("Reading from unknown location 0x{:04x}", addr),
@@ -168,15 +170,18 @@ impl Mmu {
self.ppu.oam[(addr & 0x009f) as usize] = value;
self.ppu.update_object(addr, value);
}
- 0xf00 => {
- if addr == 0xffff {
- self.ie = value;
- } else if addr >= 0xff80 {
- self.ppu.hram[(addr & 0x007f) as usize] = value;
- } else {
+ 0xf00 => match addr & 0x00ff {
+ 0x0f => {
+ self.ppu.set_int_vblank(value & 0x01 == 0x01);
+ self.timer.set_int_tima(value & 0x04 == 0x04);
+ }
+ 0x80..=0xfe => self.ppu.hram[(addr & 0x007f) as usize] = value,
+ 0xff => self.ie = value,
+ _ => {
match addr & 0x00f0 {
0x00 => match addr & 0x00ff {
0x00 => self.pad.write(addr, value),
+ 0x04..=0x07 => self.timer.write(addr, value),
_ => println!("Writing to unknown IO control 0x{:04x}", addr),
},
0x40 | 0x60 | 0x70 => {
@@ -198,7 +203,7 @@ impl Mmu {
_ => println!("Writing to unknown IO control 0x{:04x}", addr),
}
}
- }
+ },
addr => panic!("Writing in unknown location 0x{:04x}", addr),
},
addr => panic!("Writing in unknown location 0x{:04x}", addr),
diff --git a/src/ppu.rs b/src/ppu.rs
index 66a5c397a780fd1fdcadd01936fc4e7f29d27b40..c2073b2fde7864f4103b46f4840f55cf6669964f 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -498,6 +498,10 @@ impl Ppu {
self.int_vblank
}
+ pub fn set_int_vblank(&mut self, value: bool) {
+ self.int_vblank = value;
+ }
+
pub fn ack_vblank(&mut self) {
self.int_vblank = false;
}
@@ -705,10 +709,10 @@ impl Ppu {
// the object is only considered visible if it's a priority
// or if the underlying pixel is transparent (zero value)
let is_visible = obj.priority || self.color_buffer[color_offset] == 0;
- if is_visible {
+ let pixel = tile_row[if obj.xflip { 7 - x } else { x }];
+ if is_visible && pixel != 0 {
// obtains the current pixel data from the tile row and
// re-maps it according to the object palette
- let pixel = tile_row[if obj.xflip { 7 - x } else { x }];
let color = palette[pixel as usize];
// sets the color pixel in the frame buffer
diff --git a/src/timer.rs b/src/timer.rs
index 0302f9be229362cfbb4156f9d09c8190a8c398e8..0169e9e8ceec2700463b66134338174179ef1c15 100644
--- a/src/timer.rs
+++ b/src/timer.rs
@@ -3,7 +3,11 @@ pub struct Timer {
tima: u8,
tma: u8,
tac: u8,
- ratio: u16,
+ div_clock: u16,
+ tima_clock: u16,
+ tima_enabled: bool,
+ tima_ratio: u16,
+ int_tima: bool,
}
impl Timer {
@@ -13,15 +17,73 @@ impl Timer {
tima: 0,
tma: 0,
tac: 0x0,
- ratio: 1024
+ div_clock: 0,
+ tima_clock: 0,
+ tima_enabled: false,
+ tima_ratio: 1024,
+ int_tima: false,
+ }
+ }
+
+ pub fn clock(&mut self, cycles: u8) {
+ self.div_clock += cycles as u16;
+ self.tima_clock += cycles as u16;
+
+ if self.div_clock >= 256 {
+ self.div = self.div.wrapping_add(1);
+ self.div_clock = self.div_clock - 256;
+ }
+
+ if self.tima_enabled && self.tima_clock >= self.tima_ratio {
+ if self.tima == 0xff {
+ self.int_tima = true;
+ self.tima = self.tma;
+ }
+
+ self.tima = self.tima.wrapping_add(1);
+ self.tima_clock = self.tima_clock - self.tima_ratio;
}
}
pub fn read(&mut self, addr: u16) -> u8 {
- 0x00
+ match addr & 0x00ff {
+ 0x04 => self.div,
+ 0x05 => self.tima,
+ 0x06 => self.tma,
+ 0x07 => self.tac,
+ addr => panic!("Reding from unknown Timer location 0x{:04x}", addr),
+ }
}
pub fn write(&mut self, addr: u16, value: u8) {
+ match addr & 0x00ff {
+ 0x04 => self.div = 0,
+ 0x05 => self.tima = value,
+ 0x06 => self.tma = value,
+ 0x07 => {
+ self.tac = value;
+ match value & 0x03 {
+ 0x00 => self.tima_ratio = 1024,
+ 0x01 => self.tima_ratio = 16,
+ 0x02 => self.tima_ratio = 64,
+ 0x03 => self.tima_ratio = 256,
+ value => panic!("Invalid TAC value 0x{:02x}", value),
+ }
+ self.tima_enabled = value & 0x04 == 0x04;
+ }
+ addr => panic!("Writing to unknown Timer location 0x{:04x}", addr),
+ }
+ }
+
+ pub fn int_tima(&self) -> bool {
+ self.int_tima
}
-}
+ pub fn set_int_tima(&mut self, value: bool) {
+ self.int_tima = value;
+ }
+
+ pub fn ack_tima(&mut self) {
+ self.int_tima = false;
+ }
+}