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Sync CPU to cycles + Fix a few PPU desyncs
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@AnnsAnns
AnnsAnns committed Jun 13, 2024
1 parent 9f4bf92 commit 87fe71d
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Showing 2 changed files with 55 additions and 38 deletions.
4 changes: 4 additions & 0 deletions src/cpu/interrupts.rs
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
use num_enum::IntoPrimitive;

use crate::cpu::registers::Register16Bit;

use super::{instructions::InstructionResult, CPU};

#[derive(Debug, IntoPrimitive, Clone, Copy)]
Expand Down Expand Up @@ -89,6 +91,8 @@ impl CPU {
for i in 0..=4 {
// Check if the interrupt flag is set and the interrupt is enabled
if interrupt_flag & (1 << i) != 0 && interrupt_enable & (1 << i) != 0 && self.ime_flag {
log::debug!("Interrupt {:?} called", i);

// Disable all interrupts
self.ime_flag = false;

Expand Down
89 changes: 51 additions & 38 deletions src/main.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -103,6 +103,7 @@ async fn main() {
let mut scanline: u8 = 0;
let mut frame_cycles = 0;
let mut ppu_mode: PpuMode = PpuMode::OamScan;
let mut used_cpu_cycles = 0;

// Open "registers.txt" file for Gameboy Doctor
let mut gb_doctor_file = std::fs::File::create("gameboy_doctor_log.txt").unwrap();
Expand All @@ -111,41 +112,44 @@ async fn main() {
}

loop {
if DUMP_GAMEBOY_DOCTOR_LOG {
// Dump registers to file for Gameboy Doctor like this
// A:00 F:11 B:22 C:33 D:44 E:55 H:66 L:77 SP:8888 PC:9999 PCMEM:AA,BB,CC,DD
let _ = gb_doctor_file.write_all(
format!(
"A:{:02X} F:{:02X} B:{:02X} C:{:02X} D:{:02X} E:{:02X} H:{:02X} L:{:02X} SP:{:04X} PC:{:04X} PCMEM:{:02X},{:02X},{:02X},{:02X}\n",
cpu.get_8bit_register(Register8Bit::A),
cpu.flags_to_u8(),
cpu.get_8bit_register(Register8Bit::B),
cpu.get_8bit_register(Register8Bit::C),
cpu.get_8bit_register(Register8Bit::D),
cpu.get_8bit_register(Register8Bit::E),
cpu.get_8bit_register(Register8Bit::H),
cpu.get_8bit_register(Register8Bit::L),
cpu.get_16bit_register(Register16Bit::SP),
cpu.get_16bit_register(Register16Bit::PC),
cpu.get_memory().read_byte(cpu.get_16bit_register(Register16Bit::PC)),
cpu.get_memory().read_byte(cpu.get_16bit_register(Register16Bit::PC) + 1),
cpu.get_memory().read_byte(cpu.get_16bit_register(Register16Bit::PC) + 2),
cpu.get_memory().read_byte(cpu.get_16bit_register(Register16Bit::PC) + 3),
)
.as_bytes(),
);
}

let instruction = cpu.prepare_and_decode_next_instruction();
log::debug!("🔠 Instruction: {:?}", instruction);
let is_bootrom_enabled = cpu.is_boot_rom_enabled();
let result = cpu.step();
log::debug!("➡️ Result: {:?} | Bootrom: {:?}", result, is_bootrom_enabled);
if used_cpu_cycles == 0 {
if DUMP_GAMEBOY_DOCTOR_LOG {
// Dump registers to file for Gameboy Doctor like this
// A:00 F:11 B:22 C:33 D:44 E:55 H:66 L:77 SP:8888 PC:9999 PCMEM:AA,BB,CC,DD
let _ = gb_doctor_file.write_all(
format!(
"A:{:02X} F:{:02X} B:{:02X} C:{:02X} D:{:02X} E:{:02X} H:{:02X} L:{:02X} SP:{:04X} PC:{:04X} PCMEM:{:02X},{:02X},{:02X},{:02X}\n",
cpu.get_8bit_register(Register8Bit::A),
cpu.flags_to_u8(),
cpu.get_8bit_register(Register8Bit::B),
cpu.get_8bit_register(Register8Bit::C),
cpu.get_8bit_register(Register8Bit::D),
cpu.get_8bit_register(Register8Bit::E),
cpu.get_8bit_register(Register8Bit::H),
cpu.get_8bit_register(Register8Bit::L),
cpu.get_16bit_register(Register16Bit::SP),
cpu.get_16bit_register(Register16Bit::PC),
cpu.get_memory().read_byte(cpu.get_16bit_register(Register16Bit::PC)),
cpu.get_memory().read_byte(cpu.get_16bit_register(Register16Bit::PC) + 1),
cpu.get_memory().read_byte(cpu.get_16bit_register(Register16Bit::PC) + 2),
cpu.get_memory().read_byte(cpu.get_16bit_register(Register16Bit::PC) + 3),
)
.as_bytes(),
);
}

let pc_following_word = cpu
.get_memory()
.read_word(cpu.get_16bit_register(Register16Bit::PC) + 1);
log::debug!("🔢 Following Word (PC): {:#06X}", pc_following_word);
let instruction = cpu.prepare_and_decode_next_instruction();
log::debug!("🔠 Instruction: {:?}", instruction);
let is_bootrom_enabled = cpu.is_boot_rom_enabled();
let result = cpu.step();
log::debug!("➡️ Result: {:?} | Bootrom: {:?}", result, is_bootrom_enabled);
used_cpu_cycles = result.unwrap().cycles;

let pc_following_word = cpu
.get_memory()
.read_word(cpu.get_16bit_register(Register16Bit::PC) + 1);
log::debug!("🔢 Following Word (PC): {:#06X}", pc_following_word);
}

cpu.poll_inputs();
cpu.blarg_print();
Expand All @@ -155,6 +159,8 @@ async fn main() {
//log::info!("Scanline: {}", scanline);
cpu.set_lcd_y_coordinate(scanline);

let mut do_frame_cycle = true;

match ppu_mode {
PpuMode::OamScan => {
if dot % DOTS_PER_LINE >= 80 {
Expand All @@ -174,6 +180,8 @@ async fn main() {
ppu_mode = if scanline <= 143 {
PpuMode::OamScan
} else {
// Set the VBlank interrupt since we are done with the frame
cpu.set_vblank_interrupt();
PpuMode::VerticalBlank
};
}
Expand All @@ -188,15 +196,20 @@ async fn main() {
scanline = 0;
//log::info!("Frame: {} - Resetting", frame_cycles);
frame_cycles = 0;
do_frame_cycle = false;
}

scanline += 1;
if !do_frame_cycle {
scanline += 1;
}
}
}
}

cpu.set_ppu_mode(ppu_mode as u8);
frame_cycles += 1;
if do_frame_cycle {
frame_cycles += 1;
}

// Draw at 60Hz so 60 frames per second
if (ppu_time.elapsed().as_millis() as f32) >= TIME_PER_FRAME {
Expand All @@ -223,8 +236,6 @@ async fn main() {

gb_display.draw(&final_image);
next_frame().await;
// Set the VBlank interrupt since we are done with the frame
cpu.set_vblank_interrupt();
frame += 1;

// Dump memory every 3 seconds
Expand All @@ -233,5 +244,7 @@ async fn main() {
cpu.dump_memory();
}
}

used_cpu_cycles -= 1;
}
}

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