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Refined timer interrupt timing

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This commit is contained in:
Lior Halphon 2017-09-02 22:08:20 +03:00
parent cbbaf2ee84
commit 54eb51d8db
3 changed files with 7 additions and 5 deletions
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1
Core/gb.h
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@ -332,6 +332,7 @@ struct GB_gameboy_internal_s {
GB_PADDING(uint16_t, serial_cycles);
uint16_t serial_cycles; /* This field changed its meaning in v0.10 */
uint16_t serial_length;
uint8_t delayed_interrupts; /* When an interrupt occurs while not aligned to a T-cycle, it must be "delayed" */
);
/* APU */

4
Core/timing.c
View File

@ -82,10 +82,13 @@ static void GB_ir_run(GB_gameboy_t *gb)
static void advance_tima_state_machine(GB_gameboy_t *gb)
{
gb->delayed_interrupts &= ~4;
if (gb->tima_reload_state == GB_TIMA_RELOADED) {
gb->tima_reload_state = GB_TIMA_RUNNING;
}
else if (gb->tima_reload_state == GB_TIMA_RELOADING) {
gb->io_registers[GB_IO_IF] |= 4;
gb->delayed_interrupts |= 4; // Timer interrupt is not aligned to a T-cycle and therefore is effective only the next one.
gb->tima_reload_state = GB_TIMA_RELOADED;
}
}
@ -154,7 +157,6 @@ static void increase_tima(GB_gameboy_t *gb)
gb->io_registers[GB_IO_TIMA]++;
if (gb->io_registers[GB_IO_TIMA] == 0) {
gb->io_registers[GB_IO_TIMA] = gb->io_registers[GB_IO_TMA];
gb->io_registers[GB_IO_IF] |= 4;
gb->tima_reload_state = GB_TIMA_RELOADING;
}
}

7
Core/z80_cpu.c
View File

@ -1337,9 +1337,9 @@ static GB_opcode_t *opcodes[256] = {
void GB_cpu_run(GB_gameboy_t *gb)
{
gb->vblank_just_occured = false;
bool interrupt = gb->interrupt_enable & gb->io_registers[GB_IO_IF] & 0x1F;
uint8_t interrupt_queue = gb->interrupt_enable & gb->io_registers[GB_IO_IF] & 0x1F & ~gb->delayed_interrupts;
if (interrupt) {
if (interrupt_queue) {
gb->halted = false;
}
@ -1354,9 +1354,8 @@ void GB_cpu_run(GB_gameboy_t *gb)
gb->ime_toggle = false;
}
if (effecitve_ime && interrupt) {
if (effecitve_ime && interrupt_queue) {
uint8_t interrupt_bit = 0;
uint8_t interrupt_queue = gb->interrupt_enable & gb->io_registers[GB_IO_IF] & 0x1F;
while (!(interrupt_queue & 1)) {
interrupt_queue >>= 1;
interrupt_bit++;