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add timer & improve peripherals
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@commonkestrel
commonkestrel committed Dec 20, 2023
1 parent be63eb5 commit e0064bb
Showing 1 changed file with 68 additions and 12 deletions.
80 changes: 68 additions & 12 deletions src/emulator.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,9 +6,7 @@ use std::{
io::{Read, Write},
str::FromStr,
sync::{Arc, OnceLock},
fs::File,
path::Path,
time::{Duration, Instant, SystemTime, SystemTimeError},
time::{Duration, Instant},
};

use async_std::{
Expand All @@ -34,6 +32,8 @@ type ReadFn = unsafe extern "C" fn(u8) -> u8;
type StatefulReadFn = unsafe extern "C" fn(*mut c_void, u8) -> u8;
type WriteFn = unsafe extern "C" fn(u8, u8);
type StatefulWriteFn = unsafe extern "C" fn(*mut c_void, u8, u8);
type TickFn = unsafe extern "C" fn();
type StatefulTickFn = unsafe extern "C" fn(*mut c_void);
type DropFn = unsafe extern "C" fn();
type StatefulDropFn = unsafe extern "C" fn(*mut c_void);
type ResetFn = unsafe extern "C" fn();
Expand All @@ -49,12 +49,11 @@ pub enum EmulatorError {
StdIn,
#[error("unable to print to stdout")]
Out(std::io::Error),
#[error("error getting time elapsed")]
Time(#[from] SystemTimeError),
#[error("global state already set")]
OnceFull,
#[error("global state not initialized yet")]
OnceEmpty,
#[cfg(test)]
#[error("emulator timed out waiting for halt")]
Timeout,
}
Expand Down Expand Up @@ -539,6 +538,7 @@ struct State {
sp: u16,
ctrl: Control,
sreg: SReg,
timer: u16,
alu: Alu,
bus: u8,
bank: RegBank,
Expand All @@ -557,6 +557,7 @@ impl State {
sp: 0xFFBF,
ctrl: Control::default(),
sreg: SReg::empty(),
timer: 0,
alu: Alu::default(),
bus: 0,
bank: RegBank::default(),
Expand Down Expand Up @@ -610,7 +611,7 @@ impl State {
} else if cw.contains(ControlWord::LA) {
match self.addr {
0x0000..=0xFFBF => self.mem[self.addr as usize],
0xFFC0..=0xFFFE => match self.peripherals.get(&((self.addr - 0xFFC0) as u8)) {
0xFFC0..=0xFFFC => match self.peripherals.get(&((self.addr - 0xFFC0) as u8)) {
Some(periph) => unsafe {
if let Ok(stateful_read) =
periph.lib.library.get::<StatefulReadFn>(b"stateful_read")
Expand All @@ -631,6 +632,8 @@ impl State {
},
None => 0x00,
},
0xFFFD => (self.timer >> 8) as u8,
0xFFFE => (self.timer & 0xFF) as u8,
0xFFFF => self.sreg.bits(),
}
} else if cw.contains(ControlWord::PO) {
Expand All @@ -652,7 +655,7 @@ impl State {
0x0000..=0xFFBF => {
self.mem[self.addr as usize] = bus;
}
0xFFC0..=0xFFFE => match self.peripherals.get(&((self.addr - 0xFFC0) as u8)) {
0xFFC0..=0xFFFC => match self.peripherals.get(&((self.addr - 0xFFC0) as u8)) {
Some(periph) => unsafe {
if let Ok(stateful_write) =
periph.lib.library.get::<StatefulWriteFn>(b"stateful_write")
Expand All @@ -673,6 +676,12 @@ impl State {
},
None => {}
},
0xFFFD => {
self.timer = (self.timer & 0x00FF) | ((bus as u16) << 8);
}
0xFFFE => {
self.timer = (self.timer & 0xFF00) | (bus as u16);
}
0xFFFF => {
self.sreg = SReg::from_bits_retain(bus);
}
Expand Down Expand Up @@ -722,6 +731,27 @@ impl State {
}

// falling edge
for (_, peripheral) in self.peripherals.iter() {
unsafe {
if let Ok(stateful_tick) = peripheral
.lib
.library
.get::<StatefulTickFn>(b"stateful_tick")
{
match peripheral.lib.state {
Some(state) => stateful_tick(state),
None => {
eprintln!("PERIPHERAL ERROR: unable to call `stateful_tick` (state was not initialized)");
}
}
} else if let Ok(stateless_tick) = peripheral.lib.library.get::<TickFn>(b"tick") {
stateless_tick();
}
}
}

self.timer = self.timer.wrapping_add(1);

if cw.contains(ControlWord::JNZ) {
if !self.sreg.contains(SReg::Z) {
self.pc = ((self.bank.h as u16) << 8) | (self.bank.l as u16);
Expand Down Expand Up @@ -999,7 +1029,7 @@ pub async fn emulate(mut args: EmulatorArgs) -> Result<(), EmulatorError> {
.map_err(|err| EmulatorError::Out(err))?;
let stdin = spawn_stdin_channel();

let mut prev = SystemTime::now();
let mut prev = Instant::now();

loop {
match stdin.try_recv() {
Expand All @@ -1026,12 +1056,12 @@ pub async fn emulate(mut args: EmulatorArgs) -> Result<(), EmulatorError> {
let mut state = STATE.get().ok_or(EmulatorError::OnceEmpty)?.write().await;

let tick = match state.speed {
Some(speed) => prev.elapsed()? >= speed.0,
Some(speed) => prev.elapsed() >= speed.0,
None => false,
};

if tick {
prev = SystemTime::now();
prev = Instant::now();

let halted = state.tick();
if halted {
Expand Down Expand Up @@ -1270,7 +1300,7 @@ async fn single_arg(
.await
.mem[addr as usize]
}
0xFFC0..=0xFFFE => {
0xFFC0..=0xFFFC => {
match STATE
.get()
.ok_or(EmulatorError::OnceEmpty)?
Expand Down Expand Up @@ -1300,6 +1330,24 @@ async fn single_arg(
None => 0x00,
}
}
0xFFFD => {
(STATE
.get()
.ok_or(EmulatorError::OnceEmpty)?
.read()
.await
.timer
>> 8) as u8
}
0xFFFE => {
(STATE
.get()
.ok_or(EmulatorError::OnceEmpty)?
.read()
.await
.timer
& 0xFF) as u8
}
0xFFFF => STATE
.get()
.ok_or(EmulatorError::OnceEmpty)?
Expand Down Expand Up @@ -1428,7 +1476,7 @@ async fn double_arg(
.await
.mem[addr as usize] = value
}
0xFFC0..=0xFFFE => {
0xFFC0..=0xFFFC => {
match STATE
.get()
.ok_or(EmulatorError::OnceEmpty)?
Expand Down Expand Up @@ -1458,6 +1506,14 @@ async fn double_arg(
None => {}
}
}
0xFFFD => {
let mut state = STATE.get().ok_or(EmulatorError::OnceEmpty)?.write().await;
state.timer = (state.timer & 0x00FF) | ((value as u16) << 8)
}
0xFFFE => {
let mut state = STATE.get().ok_or(EmulatorError::OnceEmpty)?.write().await;
state.timer = (state.timer & 0xFF00) | ((value & 0xFF) as u16)
}
0xFFFF => {
STATE
.get()
Expand Down

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