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|
pub mod audio;
pub mod consts;
pub mod display;
pub mod gamepad;
pub mod interrupts_timers;
pub mod io;
pub mod opcodes;
pub mod state;
use crate::gamepad::Gamepad;
use crate::state::{GBState, MemError};
use clap::Parser;
use std::time::SystemTime;
use std::{thread, time};
pub fn exec_opcode(state: &mut GBState) -> Result<u64, MemError> {
let opcode = state.mem.r(state.cpu.pc)?;
if state.is_debug {
println!(
"{:02x}:{:04x} = {:02x} (IME: {})",
state.mem.rom_bank, state.cpu.pc, opcode, state.mem.ime
);
}
state.cpu.pc += 1;
let n1 = (opcode >> 3) & 0b111;
let n2 = opcode & 0b111;
match opcode >> 6 {
0b00 => opcodes::op00(state, n1, n2),
0b01 => opcodes::op01(state, n1, n2),
0b10 => opcodes::op10(state, n1, n2),
0b11 => opcodes::op11(state, n1, n2),
_ => panic!(),
}
}
#[derive(Parser)]
#[command(author, version, about, long_about = None)]
struct Cli {
/// The gameboy rom file
rom: String,
/// Setting this saves battery by using thread::sleep instead of spin_sleeping. It can result in lag and inconsistent timing.
#[arg(long)]
thread_sleep: bool,
#[arg(short, long, default_value_t = 1.0)]
speed: f32,
}
fn main() {
let cli = Cli::parse();
println!("Initializing Gamepad...");
let mut gamepad = Gamepad::new();
println!("Starting {:?}...", &cli.rom);
let mut state = GBState::new();
let save_file = format!("{}.sav", &cli.rom);
state.mem.load_rom(&cli.rom).unwrap();
if let Err(_) = state.mem.load_external_ram(&save_file) {
println!(
"\"{}\" not found. Initializing new external ram.",
save_file
);
}
let mut nanos_sleep: i128 = 0;
let mut halt_time = 0;
let mut was_previously_halted = false;
let mut last_ram_bank_enabled = false;
loop {
if was_previously_halted && !state.mem.halt {
println!("Halt cycles {}", halt_time);
halt_time = 0;
}
was_previously_halted = state.mem.halt;
let now = SystemTime::now();
let c = if !state.mem.halt {
exec_opcode(&mut state).unwrap()
} else {
halt_time += 4;
4
};
state.div_timer(c);
state.tima_timer(c);
state.update_display_interrupts(c);
state.check_interrupts().unwrap();
nanos_sleep += c as i128 * (consts::CPU_CYCLE_LENGTH_NANOS as f32 / cli.speed) as i128;
if nanos_sleep > 0 {
gamepad.update_events();
let action_button_reg = gamepad.get_action_gamepad_reg();
let direction_button_reg = gamepad.get_direction_gamepad_reg();
gamepad.check_special_actions(&mut state);
if state.mem.joypad_is_action
&& (action_button_reg & (state.mem.joypad_reg >> 4))
!= (state.mem.joypad_reg >> 4)
|| (!state.mem.joypad_is_action
&& (direction_button_reg & state.mem.joypad_reg & 0b1111)
!= (state.mem.joypad_reg & 0b1111))
{
state.mem.io[0x0f] |= 0b10000;
}
state.mem.joypad_reg = direction_button_reg | (action_button_reg << 4);
if cli.thread_sleep {
thread::sleep(time::Duration::from_nanos(nanos_sleep as u64 / 10));
} else {
while SystemTime::now().duration_since(now).unwrap().as_nanos()
< nanos_sleep as u128
{}
}
nanos_sleep =
nanos_sleep - SystemTime::now().duration_since(now).unwrap().as_nanos() as i128;
if last_ram_bank_enabled && !state.mem.ram_bank_enabled {
println!("Saving to \"{}\"...", save_file);
if let Err(_) = state.mem.save_external_ram(&save_file) {
println!("Failed to save external RAM");
}
}
last_ram_bank_enabled = state.mem.ram_bank_enabled;
}
}
}
|
