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Better sample alignment on pre-CGB-D models

This commit is contained in:
Lior Halphon 2021-01-09 16:26:56 +02:00
parent 96736fe7c5
commit 2aa171e0ea
1 changed files with 43 additions and 4 deletions
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47
Core/apu.c
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@ -394,6 +394,9 @@ static void trigger_sweep_calculation(GB_gameboy_t *gb)
/* Recalculation and overflow check only occurs after a delay */
gb->apu.square_sweep_calculate_countdown = (gb->io_registers[GB_IO_NR10] & 0x7) * 2 + 5 - gb->apu.lf_div;
if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) {
gb->apu.square_sweep_calculate_countdown += 2;
}
gb->apu.enable_zombie_calculate_stepping = false;
gb->apu.unshifted_sweep = !(gb->io_registers[GB_IO_NR10] & 0x7);
gb->apu.square_sweep_countdown = ((gb->io_registers[GB_IO_NR10] >> 4) & 7) ^ 7;
@ -618,10 +621,10 @@ void GB_apu_run(GB_gameboy_t *gb)
/* Step LFSR */
if (new_bit && !old_bit) {
step_lfsr(gb, cycles - cycles_left);
if (cycles_left == 0 && gb->apu.samples[GB_NOISE] == 0) {
gb->apu.pcm_mask[1] &= 0x0F;
}
step_lfsr(gb, cycles - cycles_left);
}
}
if (cycles_left) {
@ -823,6 +826,7 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
case GB_IO_NR14:
case GB_IO_NR24: {
/* TODO: GB_MODEL_CGB_D fails channel_1_sweep_restart_2, don't forget when adding support for this revision! */
unsigned index = reg == GB_IO_NR24? GB_SQUARE_2: GB_SQUARE_1;
bool was_active = gb->apu.is_active[index];
/* TODO: When the sample length changes right before being updated, the countdown should change to the
@ -847,6 +851,9 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
turning the APU off. */
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;
if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) {
gb->apu.square_channels[index].sample_countdown += 2;
}
}
else {
unsigned extra_delay = 0;
@ -864,6 +871,9 @@ 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;
if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) {
gb->apu.square_channels[index].sample_countdown += 2;
}
}
gb->apu.square_channels[index].current_volume = gb->io_registers[index == GB_SQUARE_1 ? GB_IO_NR12 : GB_IO_NR22] >> 4;
@ -893,6 +903,9 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
if (gb->io_registers[GB_IO_NR10] & 7) {
/* APU bug: if shift is nonzero, overflow check also occurs on trigger */
gb->apu.square_sweep_calculate_countdown = (gb->io_registers[GB_IO_NR10] & 0x7) * 2 + 5 - gb->apu.lf_div;
if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) {
gb->apu.square_sweep_calculate_countdown += 2;
}
gb->apu.enable_zombie_calculate_stepping = false;
gb->apu.unshifted_sweep = false;
if (!was_active) {
@ -905,6 +918,9 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
gb->apu.sweep_length_addend = 0;
}
gb->apu.channel_1_restart_hold = 2 - gb->apu.lf_div + GB_is_cgb(gb) * 2;
if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) {
gb->apu.channel_1_restart_hold += 2;
}
gb->apu.square_sweep_countdown = ((gb->io_registers[GB_IO_NR10] >> 4) & 7) ^ 7;
}
}
@ -1080,10 +1096,23 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
gb->apu.channel_4_delta = 0;
gb->apu.noise_channel.counter_countdown = divisor + 4;
if (divisor == 2) {
gb->apu.noise_channel.counter_countdown += 1 - gb->apu.lf_div;
if (gb->model <= GB_MODEL_CGB_C) {
gb->apu.noise_channel.counter_countdown += gb->apu.lf_div;
if (!gb->cgb_double_speed) {
gb->apu.noise_channel.counter_countdown -= 1;
}
}
else {
gb->apu.noise_channel.counter_countdown += 1 - gb->apu.lf_div;
}
}
else {
gb->apu.noise_channel.counter_countdown += (uint8_t[]){2, 1, 0, 3}[gb->apu.noise_channel.alignment & 3];
if (gb->model <= GB_MODEL_CGB_C) {
gb->apu.noise_channel.counter_countdown += (uint8_t[]){2, 1, 4, 3}[gb->apu.noise_channel.alignment & 3];
}
else {
gb->apu.noise_channel.counter_countdown += (uint8_t[]){2, 1, 0, 3}[gb->apu.noise_channel.alignment & 3];
}
if (((gb->apu.noise_channel.alignment + 1) & 3) < 2) {
if ((gb->io_registers[GB_IO_NR43] & 0x07) == 1) {
gb->apu.noise_channel.counter_countdown -= 2;
@ -1094,7 +1123,17 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
}
}
}
/* TODO: These two are quite weird. Verify further */
if (gb->model <= GB_MODEL_CGB_C && gb->cgb_double_speed) {
if (!(gb->io_registers[GB_IO_NR43] & 0xF0) && (gb->io_registers[GB_IO_NR43] & 0x07)) {
gb->apu.noise_channel.counter_countdown -= 1;
}
else if ((gb->io_registers[GB_IO_NR43] & 0xF0) && !(gb->io_registers[GB_IO_NR43] & 0x07)) {
gb->apu.noise_channel.counter_countdown += 1;
}
}
gb->apu.noise_channel.current_volume = gb->io_registers[GB_IO_NR42] >> 4;
/* The volume changes caused by NRX4 sound start take effect instantly (i.e. the effect the previously