mirror of https://github.com/bsnes-emu/bsnes.git
Improved emulation of the volume envelope
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parent
e7a5be70c2
commit
6d2d88648e
19
Core/apu.c
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)
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{
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uint8_t nrx2 = gb->io_registers[index == GB_SQUARE_1? GB_IO_NR12 : GB_IO_NR22];
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if (gb->apu.square_channels[index].volume_countdown || (nrx2 & 7)) {
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if (!gb->apu.square_channels[index].volume_countdown || !--gb->apu.square_channels[index].volume_countdown) {
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gb->apu.square_channels[index].volume_countdown = nrx2 & 7;
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if (!(nrx2 & 7)) return;
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if (gb->cgb_double_speed) {
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if (index == GB_SQUARE_1) {
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gb->apu.pcm_mask[0] &= gb->apu.square_channels[GB_SQUARE_1].current_volume | 0xF1;
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@ -352,21 +353,21 @@ static void tick_square_envelope(GB_gameboy_t *gb, enum GB_CHANNELS index)
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gb->apu.square_channels[index].current_volume--;
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}
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gb->apu.square_channels[index].volume_countdown = nrx2 & 7;
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if (gb->apu.is_active[index]) {
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update_square_sample(gb, index);
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}
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}
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}
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}
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static void tick_noise_envelope(GB_gameboy_t *gb)
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{
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uint8_t nr42 = gb->io_registers[GB_IO_NR42];
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if (gb->apu.noise_channel.volume_countdown || (nr42 & 7)) {
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if (!gb->apu.noise_channel.volume_countdown || !--gb->apu.noise_channel.volume_countdown) {
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gb->apu.noise_channel.volume_countdown = nr42 & 7;
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if (!(nr42 & 7)) return;
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if (gb->cgb_double_speed) {
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gb->apu.pcm_mask[0] &= (gb->apu.noise_channel.current_volume << 2) | 0x1F;
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}
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@ -378,7 +379,6 @@ static void tick_noise_envelope(GB_gameboy_t *gb)
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gb->apu.noise_channel.current_volume--;
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}
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gb->apu.noise_channel.volume_countdown = nr42 & 7;
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if (gb->apu.is_active[GB_NOISE]) {
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update_sample(gb, GB_NOISE,
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@ -388,7 +388,6 @@ static void tick_noise_envelope(GB_gameboy_t *gb)
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}
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}
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}
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}
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static void trigger_sweep_calculation(GB_gameboy_t *gb)
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{
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@ -931,10 +930,6 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
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case GB_IO_NR12:
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case GB_IO_NR22: {
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unsigned index = reg == GB_IO_NR22? GB_SQUARE_2: GB_SQUARE_1;
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if (((value & 0x7) == 0) && ((gb->io_registers[reg] & 0x7) != 0)) {
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/* Envelope disabled */
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gb->apu.square_channels[index].volume_countdown = 0;
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}
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if ((value & 0xF8) == 0) {
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/* This disables the DAC */
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gb->io_registers[reg] = value;
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@ -1179,10 +1174,6 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
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}
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case GB_IO_NR42: {
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if (((value & 0x7) == 0) && ((gb->io_registers[reg] & 0x7) != 0)) {
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/* Envelope disabled */
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gb->apu.noise_channel.volume_countdown = 0;
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}
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if ((value & 0xF8) == 0) {
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/* This disables the DAC */
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gb->io_registers[reg] = value;
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