0xrsydn/gameboy-rust
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feat(io): model disabled sound and disconnected serial state

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0xrsydn 2026-10-07 00:44:46 +07:00
commit cb2772cef8
5 changed files with 318 additions and 6 deletions
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23
crates/gba-core/src/io.rs
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@ -1,7 +1,13 @@
//! GBA I/O subset: DMA, timers, interrupts, WAITCNT, display, and keypad input.
//! GBA I/O subset: DMA, timers, interrupts, WAITCNT, display, keypad input,
//! disabled sound state, and disconnected serial initialization.
//! Timers share a free-running prescaler phase. Hardware startup/write delays,
//! audio events, and interrupt delivery delays are not modeled.
mod inactive;
pub use inactive::{
JOYCNT, JOY_RECV, JOY_TRANS, RCNT, SIOCNT, SIODATA32, SIODATA8, SOUNDBIAS, SOUNDCNT_H,
SOUNDCNT_X, SOUND_START, WAVE_RAM,
};
mod timer_step;
pub(crate) use timer_step::TimerStep;
use timer_step::TIMER_IRQ_MASK;
@ -150,6 +156,7 @@ enum PowerState {
#[derive(Debug, Default, Clone, PartialEq, Eq)]
pub(crate) struct Io {
inactive: inactive::Inactive,
timers: [Timer; 4],
// Low ten system-clock bits cover every supported divider. STOP freezes this phase.
timer_phase: u16,
@ -174,10 +181,18 @@ pub(crate) struct Io {
impl Io {
pub(crate) fn mapped(address: u32) -> bool {
matches!(address, 0x0400_0000..=0x0400_0057 | DMA_BASE..=DMA_END | 0x0400_0100..=0x0400_010f | 0x0400_0130..=0x0400_0133 | 0x0400_0200..=0x0400_020b | POSTFLG..=0x0400_0303)
inactive::Inactive::mapped(address)
|| matches!(address, 0x0400_0000..=0x0400_0057 | DMA_BASE..=DMA_END | 0x0400_0100..=0x0400_010f | 0x0400_0130..=0x0400_0133 | 0x0400_0200..=0x0400_020b | POSTFLG..=0x0400_0303)
}
pub(crate) fn unsupported_write(address: u32, value: u8) -> Option<&'static str> {
inactive::Inactive::unsupported(address, value)
}
pub(crate) fn read8(&self, address: u32) -> Option<u8> {
if inactive::Inactive::mapped(address) {
return self.inactive.read8(address);
}
if (DMA_BASE..=DMA_END).contains(&address) {
return Some(self.dma.read8(address));
}
@ -216,6 +231,10 @@ impl Io {
pub(crate) fn write8(&mut self, address: u32, value: u8) {
debug_assert!(Self::mapped(address));
debug_assert!(!(KEYINPUT..=KEYCNT + 1).contains(&address));
if inactive::Inactive::mapped(address) {
self.inactive.write8(address, value);
return;
}
if (DMA_BASE..=DMA_END).contains(&address) {
self.dma.write8(address, value);
return;