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fix(serial): gate RCNT interrupt and Joybus controls by mode

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0xrsydn 2026-10-07 03:10:04 +07:00
commit 86f8663904
7 changed files with 203 additions and 20 deletions
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8
crates/gba-core/src/io/inactive.rs
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@ -28,12 +28,14 @@ impl Inactive {
/// Value-dependent rejection is independent of device state, so batch
/// stores can validate all values before committing any RAM/I/O writes.
/// RCNT mode and IRQ-enable bits share the high byte. Each high-byte write
/// supplies the complete selection, independent of the previous low byte.
pub(super) fn unsupported(address: u32, value: u8) -> Option<&'static str> {
match address {
SIOCNT if value & 0x80 != 0 => Some("serial transfer start"),
0x0400_0129 if value & 0x20 != 0 => Some("multiplayer/UART serial mode"),
0x0400_0135 if value & 0x40 != 0 => Some("Joybus serial mode"),
0x0400_0135 if value & 1 != 0 => Some("GPIO serial interrupt enable"),
0x0400_0135 if value & 0xc0 == 0xc0 => Some("Joybus serial mode"),
0x0400_0135 if value & 0x81 == 0x81 => Some("GPIO serial interrupt enable"),
JOYCNT if value & 0x40 != 0 => Some("Joybus interrupt enable"),
JOY_RECV..=0x0400_0157 if value != 0 => Some("Joybus data access beyond reset"),
_ => None,
@ -83,7 +85,7 @@ impl Inactive {
self.serial_control = replace_byte(self.serial_control, address, value) & 0x500b
}
SIODATA8 if address & 1 == 0 => self.serial_send = value,
RCNT => self.rcnt = replace_byte(self.rcnt, address, value) & 0x80ff,
RCNT => self.rcnt = replace_byte(self.rcnt, address, value) & 0xc1ff,
_ => {} // Unused/read-only bits have no effect.
}
}