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Fix several square channel zombie stepping quirks

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This commit is contained in:
Lior Halphon 2022-03-12 00:49:43 +02:00
parent 5e119548e9
commit ab109da683
2 changed files with 19 additions and 5 deletions
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22
Core/apu.c
View File

@ -691,6 +691,14 @@ void GB_apu_run(GB_gameboy_t *gb, bool force)
unrolled for (unsigned i = GB_SQUARE_1; i <= GB_SQUARE_2; i++) {
if (gb->apu.is_active[i]) {
uint16_t cycles_left = cycles;
if (unlikely(gb->apu.square_channels[i].delay)) {
if (gb->apu.square_channels[i].delay < cycles_left) {
gb->apu.square_channels[i].delay = 0;
}
else {
gb->apu.square_channels[i].delay -= cycles_left;
}
}
while (unlikely(cycles_left > gb->apu.square_channels[i].sample_countdown)) {
cycles_left -= gb->apu.square_channels[i].sample_countdown + 1;
gb->apu.square_channels[i].sample_countdown = (gb->apu.square_channels[i].sample_length ^ 0x7FF) * 2 + 1;
@ -700,7 +708,7 @@ void GB_apu_run(GB_gameboy_t *gb, bool force)
if (cycles_left == 0 && gb->apu.samples[i] == 0) {
gb->apu.pcm_mask[0] &= i == GB_SQUARE_1? 0xF0 : 0x0F;
}
gb->apu.square_channels[i].did_tick = true;
update_square_sample(gb, i);
}
if (cycles_left) {
@ -1099,7 +1107,8 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
/* On an AGB, as well as on CGB C and earlier (TODO: Tested: 0, B and C), it behaves slightly different on
double speed. */
if (gb->model == GB_MODEL_CGB_E || gb->model == GB_MODEL_CGB_D || gb->apu.square_channels[index].sample_countdown & 1) {
if (gb->apu.square_channels[index].sample_countdown >> 1 == (gb->apu.square_channels[index].sample_length ^ 0x7FF)) {
if (gb->apu.square_channels[index].did_tick &&
gb->apu.square_channels[index].sample_countdown >> 1 == (gb->apu.square_channels[index].sample_length ^ 0x7FF)) {
gb->apu.square_channels[index].current_sample_index--;
gb->apu.square_channels[index].current_sample_index &= 7;
gb->apu.square_channels[index].sample_surpressed = false;
@ -1115,8 +1124,10 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
turning the APU off. */
gb->apu.square_channels[index].envelope_clock.locked = false;
gb->apu.square_channels[index].envelope_clock.clock = false;
gb->apu.square_channels[index].did_tick = false;
if (!gb->apu.is_active[index]) {
gb->apu.square_channels[index].sample_countdown = (gb->apu.square_channels[index].sample_length ^ 0x7FF) * 2 + 6 - gb->apu.lf_div;
gb->apu.square_channels[index].delay = 6 - gb->apu.lf_div;
gb->apu.square_channels[index].sample_countdown = (gb->apu.square_channels[index].sample_length ^ 0x7FF) * 2 + gb->apu.square_channels[index].delay;
if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) {
gb->apu.square_channels[index].sample_countdown += 2;
}
@ -1124,7 +1135,7 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
else {
unsigned extra_delay = 0;
if (gb->model == GB_MODEL_CGB_E || gb->model == GB_MODEL_CGB_D) {
if (!(value & 4) && !(((gb->apu.square_channels[index].sample_countdown - 1) / 2) & 0x400)) {
if (!(value & 4) && !(((gb->apu.square_channels[index].sample_countdown - 1 - gb->apu.square_channels[index].delay) / 2) & 0x400)) {
gb->apu.square_channels[index].current_sample_index++;
gb->apu.square_channels[index].current_sample_index &= 0x7;
gb->apu.square_channels[index].sample_surpressed = false;
@ -1137,7 +1148,8 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
}
}
/* Timing quirk: if already active, sound starts 2 (2MHz) ticks earlier.*/
gb->apu.square_channels[index].sample_countdown = (gb->apu.square_channels[index].sample_length ^ 0x7FF) * 2 + 4 - gb->apu.lf_div + extra_delay;
gb->apu.square_channels[index].delay = 4 - gb->apu.lf_div + extra_delay;
gb->apu.square_channels[index].sample_countdown = (gb->apu.square_channels[index].sample_length ^ 0x7FF) * 2 + gb->apu.square_channels[index].delay;
if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) {
gb->apu.square_channels[index].sample_countdown += 2;
}

2
Core/apu.h
View File

@ -88,6 +88,8 @@ typedef struct
uint16_t sample_length; // From NRX3, NRX4, in APU ticks
bool length_enabled; // NRX4
GB_envelope_clock_t envelope_clock;
uint8_t delay; // Hack for CGB D/E phantom step due to how sample_countdown is implemented in SameBoy
bool did_tick;
} square_channels[2];
struct {