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More sweep improvements

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This commit is contained in:
Lior Halphon 2020-12-01 22:37:13 +02:00
parent 13bc8679f9
commit 1baa0446a9
2 changed files with 23 additions and 7 deletions
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23
Core/apu.c
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@ -337,11 +337,13 @@ static void trigger_sweep_calculation(GB_gameboy_t *gb)
gb->apu.sweep_length_addend + gb->apu.shadow_sweep_sample_length + !!(gb->io_registers[GB_IO_NR10] & 0x8);
gb->apu.square_channels[GB_SQUARE_1].sample_length &= 0x7FF;
}
if (gb->apu.channel_1_restart_hold == 0) {
gb->apu.sweep_length_addend = gb->apu.square_channels[GB_SQUARE_1].sample_length;
gb->apu.sweep_length_addend >>= (gb->io_registers[GB_IO_NR10] & 7);
}
/* Recalculation and overflow check only occurs after a delay */
gb->apu.square_sweep_calculate_countdown = (gb->io_registers[GB_IO_NR10] & 0x7) * 2 + 7 - gb->apu.lf_div;
gb->apu.square_sweep_calculate_countdown = (gb->io_registers[GB_IO_NR10] & 0x7) * 2 + 5 - gb->apu.lf_div;
gb->apu.square_sweep_countdown = ((gb->io_registers[GB_IO_NR10] >> 4) & 7) ^ 7;
}
@ -440,7 +442,9 @@ void GB_apu_run(GB_gameboy_t *gb)
}
else {
/* APU bug: sweep frequency is checked after adding the sweep delta twice */
if (gb->apu.channel_1_restart_hold == 0) {
gb->apu.shadow_sweep_sample_length = gb->apu.square_channels[GB_SQUARE_1].sample_length;
}
if (gb->io_registers[GB_IO_NR10] & 8) {
gb->apu.sweep_length_addend ^= 0x7FF;
}
@ -452,6 +456,15 @@ void GB_apu_run(GB_gameboy_t *gb)
}
}
if (gb->apu.channel_1_restart_hold) {
if (gb->apu.channel_1_restart_hold > cycles) {
gb->apu.channel_1_restart_hold -= cycles;
}
else {
gb->apu.channel_1_restart_hold = 0;
}
}
UNROLL
for (unsigned i = GB_SQUARE_1; i <= GB_SQUARE_2; i++) {
if (gb->apu.is_active[i]) {
@ -665,7 +678,9 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
case GB_IO_NR10:{
bool old_negate = gb->io_registers[GB_IO_NR10] & 8;
gb->io_registers[GB_IO_NR10] = value;
if (gb->apu.shadow_sweep_sample_length + gb->apu.sweep_length_addend + old_negate > 0x7FF && !(value & 8)) {
if (gb->apu.square_sweep_calculate_countdown == 0 &&
gb->apu.shadow_sweep_sample_length + gb->apu.sweep_length_addend + old_negate > 0x7FF &&
!(value & 8)) {
gb->apu.is_active[GB_SQUARE_1] = false;
update_sample(gb, GB_SQUARE_1, 0, 0);
}
@ -765,17 +780,17 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
}
if (index == GB_SQUARE_1) {
gb->apu.shadow_sweep_sample_length = 0;
if (gb->io_registers[GB_IO_NR10] & 7) {
/* APU bug: if shift is nonzero, overflow check also occurs on trigger */
gb->apu.shadow_sweep_sample_length = gb->apu.square_channels[GB_SQUARE_1].sample_length;
gb->apu.square_sweep_calculate_countdown = (gb->io_registers[GB_IO_NR10] & 0x7) * 2 + 7 - gb->apu.lf_div;
gb->apu.sweep_length_addend = gb->apu.square_channels[GB_SQUARE_1].sample_length;
gb->apu.sweep_length_addend >>= (gb->io_registers[GB_IO_NR10] & 7);
}
else {
gb->apu.shadow_sweep_sample_length = 0;
gb->apu.sweep_length_addend = 0;
}
gb->apu.channel_1_restart_hold = 4 - gb->apu.lf_div;
gb->apu.square_sweep_countdown = ((gb->io_registers[GB_IO_NR10] >> 4) & 7) ^ 7;
}
}

1
Core/apu.h
View File

@ -120,6 +120,7 @@ typedef struct
uint8_t skip_div_event;
bool current_lfsr_sample;
uint8_t pcm_mask[2]; // For CGB-0 to CGB-C PCM read glitch
uint8_t channel_1_restart_hold;
} GB_apu_t;
typedef enum {