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Corrected behavior for channel 1 and 2 restart

This commit is contained in:
Lior Halphon 2017-09-22 02:04:29 +03:00
parent 882b141478
commit 8f4cd5c412
2 changed files with 3 additions and 12 deletions
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14
Core/apu.c
View File

@ -267,7 +267,6 @@ void GB_apu_run(GB_gameboy_t *gb)
duties[gb->apu.square_channels[i].current_sample_index + duty * 8]?
gb->apu.square_channels[i].current_volume : 0,
cycles - cycles_left);
gb->apu.square_channels[i].sample_emitted = true;
}
if (cycles_left) {
gb->apu.square_channels[i].sample_countdown -= cycles_left;
@ -530,22 +529,15 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
gb->apu.square_channels[0].sample_length;
}
if (value & 0x80) {
gb->apu.square_channels[index].current_sample_index = 7;
if (!gb->apu.is_active[index]) {
gb->apu.square_channels[index].current_sample_index = 7;
gb->apu.square_channels[index].sample_countdown = (gb->apu.square_channels[index].sample_length ^ 0x7FF) * 2 + 6 - gb->apu.lf_div;
}
else {
/* Timing quirk: if already active, sound starts 2 (2MHz) ticks earlier.
if both active AND already emitted a sample, sound starts the next 1MHz tick,
and one sample is skipped */
if (!gb->apu.square_channels[index].sample_emitted) {
gb->apu.square_channels[index].sample_countdown = (gb->apu.square_channels[index].sample_length ^ 0x7FF) * 2 + 4 - gb->apu.lf_div;
}
else {
gb->apu.square_channels[index].sample_countdown = gb->apu.lf_div;
gb->apu.square_channels[index].current_sample_index = 0;
}
The current sample index remains unchanged! */
gb->apu.square_channels[index].sample_countdown = (gb->apu.square_channels[index].sample_length ^ 0x7FF) * 2 + 4 - gb->apu.lf_div;
}
gb->apu.square_channels[index].current_volume = gb->io_registers[index == GB_SQUARE_1 ? GB_IO_NR12 : GB_IO_NR22] >> 4;
gb->apu.square_channels[index].volume_countdown = gb->io_registers[index == GB_SQUARE_1 ? GB_IO_NR12 : GB_IO_NR22] & 7;

1
Core/apu.h
View File

@ -59,7 +59,6 @@ typedef struct
uint8_t current_volume; // Reloaded from NRX2
uint8_t volume_countdown; // Reloaded from NRX2
uint8_t current_sample_index;
bool sample_emitted;
uint16_t sample_countdown; // in APU ticks (Reloaded from sample_length, xorred $7FF)
uint16_t sample_length; // From NRX3, NRX4, in APU ticks