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Improved emulation of the volume envelope

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This commit is contained in:
Lior Halphon 2021-02-22 01:10:14 +02:00
parent e7a5be70c2
commit 6d2d88648e
1 changed files with 38 additions and 47 deletions
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19
Core/apu.c
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@ -333,8 +333,9 @@ static void tick_square_envelope(GB_gameboy_t *gb, enum GB_CHANNELS index)
{
uint8_t nrx2 = gb->io_registers[index == GB_SQUARE_1? GB_IO_NR12 : GB_IO_NR22];
if (gb->apu.square_channels[index].volume_countdown || (nrx2 & 7)) {
if (!gb->apu.square_channels[index].volume_countdown || !--gb->apu.square_channels[index].volume_countdown) {
gb->apu.square_channels[index].volume_countdown = nrx2 & 7;
if (!(nrx2 & 7)) return;
if (gb->cgb_double_speed) {
if (index == GB_SQUARE_1) {
gb->apu.pcm_mask[0] &= gb->apu.square_channels[GB_SQUARE_1].current_volume | 0xF1;
@ -352,21 +353,21 @@ static void tick_square_envelope(GB_gameboy_t *gb, enum GB_CHANNELS index)
gb->apu.square_channels[index].current_volume--;
}
gb->apu.square_channels[index].volume_countdown = nrx2 & 7;
if (gb->apu.is_active[index]) {
update_square_sample(gb, index);
}
}
}
}
static void tick_noise_envelope(GB_gameboy_t *gb)
{
uint8_t nr42 = gb->io_registers[GB_IO_NR42];
if (gb->apu.noise_channel.volume_countdown || (nr42 & 7)) {
if (!gb->apu.noise_channel.volume_countdown || !--gb->apu.noise_channel.volume_countdown) {
gb->apu.noise_channel.volume_countdown = nr42 & 7;
if (!(nr42 & 7)) return;
if (gb->cgb_double_speed) {
gb->apu.pcm_mask[0] &= (gb->apu.noise_channel.current_volume << 2) | 0x1F;
}
@ -378,7 +379,6 @@ static void tick_noise_envelope(GB_gameboy_t *gb)
gb->apu.noise_channel.current_volume--;
}
gb->apu.noise_channel.volume_countdown = nr42 & 7;
if (gb->apu.is_active[GB_NOISE]) {
update_sample(gb, GB_NOISE,
@ -388,7 +388,6 @@ static void tick_noise_envelope(GB_gameboy_t *gb)
}
}
}
}
static void trigger_sweep_calculation(GB_gameboy_t *gb)
{
@ -931,10 +930,6 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
case GB_IO_NR12:
case GB_IO_NR22: {
unsigned index = reg == GB_IO_NR22? GB_SQUARE_2: GB_SQUARE_1;
if (((value & 0x7) == 0) && ((gb->io_registers[reg] & 0x7) != 0)) {
/* Envelope disabled */
gb->apu.square_channels[index].volume_countdown = 0;
}
if ((value & 0xF8) == 0) {
/* This disables the DAC */
gb->io_registers[reg] = value;
@ -1179,10 +1174,6 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
}
case GB_IO_NR42: {
if (((value & 0x7) == 0) && ((gb->io_registers[reg] & 0x7) != 0)) {
/* Envelope disabled */
gb->apu.noise_channel.volume_countdown = 0;
}
if ((value & 0xF8) == 0) {
/* This disables the DAC */
gb->io_registers[reg] = value;