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Fix #228

This commit is contained in:
Lior Halphon 2020-02-01 23:36:16 +02:00
parent 38ee020653
commit b806ae4e82
2 changed files with 14 additions and 5 deletions
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14
Core/apu.c
View File

@ -329,11 +329,16 @@ static void tick_noise_envelope(GB_gameboy_t *gb)
void GB_apu_div_event(GB_gameboy_t *gb)
{
if (!gb->apu.global_enable) return;
if (gb->apu.skip_div_event) {
gb->apu.skip_div_event = false;
if (gb->apu.skip_div_event == GB_SKIP_DIV_EVENT_SKIP) {
gb->apu.skip_div_event = GB_SKIP_DIV_EVENT_SKIPPED;
return;
}
gb->apu.div_divider++;
if (gb->apu.skip_div_event == GB_SKIP_DIV_EVENT_SKIPPED) {
gb->apu.skip_div_event = GB_SKIP_DIV_EVENT_INACTIVE;
}
else {
gb->apu.div_divider++;
}
if ((gb->apu.div_divider & 1) == 0) {
for (unsigned i = GB_SQUARE_2 + 1; i--;) {
@ -534,7 +539,8 @@ void GB_apu_init(GB_gameboy_t *gb)
/* APU glitch: When turning the APU on while DIV's bit 4 (or 5 in double speed mode) is on,
the first DIV/APU event is skipped. */
if (gb->div_counter & (gb->cgb_double_speed? 0x2000 : 0x1000)) {
gb->apu.skip_div_event = true;
gb->apu.skip_div_event = GB_SKIP_DIV_EVENT_SKIP;
gb->apu.div_divider = 1;
}
}

5
Core/apu.h
View File

@ -114,7 +114,10 @@ typedef struct
} noise_channel;
bool skip_div_event;
#define GB_SKIP_DIV_EVENT_INACTIVE 0
#define GB_SKIP_DIV_EVENT_SKIPPED 1
#define GB_SKIP_DIV_EVENT_SKIP 2
uint8_t skip_div_event;
bool current_lfsr_sample;
} GB_apu_t;