0xrsydn/gameboy-rust
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feat(serial): support disconnected Joybus configuration and local registers

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0xrsydn 2026-10-07 06:36:54 +07:00
commit 7546d17630
15 changed files with 462 additions and 62 deletions
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24
crates/gba-core/tests/serial_control.rs
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@ -14,7 +14,7 @@ fn memory() -> Memory {
#[test]
fn rcnt_high_byte_selection_is_independent_of_previous_mode_and_low_byte() {
let mut bus = memory();
for previous in [0x8000, 0x80f5, 0x0100, 0x4100] {
for previous in [0x8000, 0x80f5, 0x0100, 0x4100, 0xc155] {
for low in [0, 0x55, 0xff] {
for high in 0..=u8::MAX {
for halfword in [false, true] {
@ -28,25 +28,21 @@ fn rcnt_high_byte_selection_is_independent_of_previous_mode_and_low_byte() {
// Decode individual mode bits, separately from the implementation masks.
let gpio_or_joybus = high & 0x80 != 0;
let joybus = gpio_or_joybus && high & 0x40 != 0;
let gpio_irq = gpio_or_joybus && high & 1 != 0;
if joybus || gpio_irq {
let gpio_irq = gpio_or_joybus && !joybus && high & 1 != 0;
if gpio_irq {
assert_eq!(
result,
Err(MemoryError::UnsupportedIo {
address: RCNT + 1,
value: high,
operation: if joybus {
"Joybus serial mode"
} else {
"GPIO serial interrupt enable"
},
operation: "GPIO serial interrupt enable",
})
);
assert_eq!((bus.read8(RCNT), bus.read8(RCNT + 1)), before);
} else {
result.unwrap();
assert_eq!(bus.read8(RCNT + 1).unwrap(), high & 0xc1);
if gpio_or_joybus {
if gpio_or_joybus && !joybus {
let latch = if halfword { low } else { previous as u8 };
let outputs = latch >> 4;
let pins = (latch & outputs | !outputs) & 15;
@ -109,17 +105,13 @@ fn cpu_byte_and_halfword_writes_accept_inactive_bits_but_reject_active_modes_ato
for high in [1, 0x41, 0x81, 0xc0, 0xc1] {
let mut machine = prepared_store(instruction, address, high << shift);
let cpu = machine.cpu().clone();
if high & 0x80 == 0 {
if high != 0x81 {
assert_eq!(machine.step().unwrap(), StepKind::Instruction);
assert_eq!(machine.memory().read8(RCNT + 1).unwrap(), high as u8);
assert!(machine.cycles() > 0);
} else {
let error = machine.step().unwrap_err();
assert!(error.to_string().contains(if high & 0x40 != 0 {
"Joybus serial mode"
} else {
"GPIO serial interrupt enable"
}));
assert!(error.to_string().contains("GPIO serial interrupt enable"));
assert_eq!(machine.cpu(), &cpu);
assert_eq!(machine.cycles(), 0);
assert_eq!(machine.memory().read16(RCNT).unwrap(), 0x80f5);
@ -132,7 +124,7 @@ fn cpu_byte_and_halfword_writes_accept_inactive_bits_but_reject_active_modes_ato
#[test]
fn dma_halfword_rejection_is_retryable_then_inactive_configuration_completes() {
for high in [0x81, 0xc0, 0xc1] {
for high in [0x81, 0x83, 0xbf] {
let mut bus = memory();
bus.write16(RCNT, 0x80f5).unwrap();
bus.write16(0x02000000, high << 8).unwrap();