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More accurate channel 3 restarts

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This commit is contained in:
Lior Halphon 2021-10-17 02:06:33 +03:00
parent f1b8164613
commit 7ef198ec50
4 changed files with 45 additions and 39 deletions
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57
Core/apu.c
View File

@ -289,6 +289,19 @@ static void update_square_sample(GB_gameboy_t *gb, unsigned index)
0);
}
static inline void update_wave_sample(GB_gameboy_t *gb, unsigned cycles)
{
if (gb->apu.wave_channel.current_sample_index & 1) {
update_sample(gb, GB_WAVE,
(gb->apu.wave_channel.current_sample_byte & 0xF) >> gb->apu.wave_channel.shift,
cycles);
}
else {
update_sample(gb, GB_WAVE,
(gb->apu.wave_channel.current_sample_byte >> 4) >> gb->apu.wave_channel.shift,
cycles);
}
}
/* the effects of NRX2 writes on current volume are not well documented and differ
between models and variants. The exact behavior can only be verified on CGB as it
@ -665,11 +678,9 @@ void GB_apu_run(GB_gameboy_t *gb)
gb->apu.wave_channel.sample_countdown = gb->apu.wave_channel.sample_length ^ 0x7FF;
gb->apu.wave_channel.current_sample_index++;
gb->apu.wave_channel.current_sample_index &= 0x1F;
gb->apu.wave_channel.current_sample =
gb->apu.wave_channel.wave_form[gb->apu.wave_channel.current_sample_index];
update_sample(gb, GB_WAVE,
gb->apu.wave_channel.current_sample >> gb->apu.wave_channel.shift,
cycles - cycles_left);
gb->apu.wave_channel.current_sample_byte =
gb->io_registers[GB_IO_WAV_START + (gb->apu.wave_channel.current_sample_index >> 1)];
update_wave_sample(gb, cycles - cycles_left);
gb->apu.wave_channel.wave_form_just_read = true;
}
if (cycles_left) {
@ -729,11 +740,6 @@ void GB_apu_run(GB_gameboy_t *gb)
void GB_apu_init(GB_gameboy_t *gb)
{
memset(&gb->apu, 0, sizeof(gb->apu));
/* Restore the wave form */
for (unsigned reg = GB_IO_WAV_START; reg <= GB_IO_WAV_END; reg++) {
gb->apu.wave_channel.wave_form[(reg - GB_IO_WAV_START) * 2] = gb->io_registers[reg] >> 4;
gb->apu.wave_channel.wave_form[(reg - GB_IO_WAV_START) * 2 + 1] = gb->io_registers[reg] & 0xF;
}
gb->apu.lf_div = 1;
gb->apu.wave_channel.shift = 4;
/* APU glitch: When turning the APU on while DIV's bit 4 (or 5 in double speed mode) is on,
@ -1150,6 +1156,15 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
case GB_IO_NR30:
gb->apu.wave_channel.enable = value & 0x80;
if (!gb->apu.wave_channel.enable) {
if (gb->apu.is_active[GB_WAVE]) {
// Todo: I assume this happens on pre-CGB models; test this with an audible test
if (gb->apu.wave_channel.sample_countdown == 0 && gb->model < GB_MODEL_AGB) {
gb->apu.wave_channel.current_sample_byte = gb->io_registers[GB_IO_WAV_START + 5]; // what the actual fuck? Why specifically this wave address ?
}
else if (gb->apu.wave_channel.wave_form_just_read && gb->model <= GB_MODEL_CGB_C) {
gb->apu.wave_channel.current_sample_byte = gb->io_registers[GB_IO_WAV_START + 0xA]; // what the actual fuck? Why specifically this wave address?
}
}
gb->apu.is_active[GB_WAVE] = false;
update_sample(gb, GB_WAVE, 0, 0);
}
@ -1160,7 +1175,7 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
case GB_IO_NR32:
gb->apu.wave_channel.shift = (uint8_t[]){4, 0, 1, 2}[(value >> 5) & 3];
if (gb->apu.is_active[GB_WAVE]) {
update_sample(gb, GB_WAVE, gb->apu.wave_channel.current_sample >> gb->apu.wave_channel.shift, 0);
update_wave_sample(gb, 0);
}
break;
case GB_IO_NR33:
@ -1187,26 +1202,24 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
are all deterministic. */
if (offset < 4) {
gb->io_registers[GB_IO_WAV_START] = gb->io_registers[GB_IO_WAV_START + offset];
gb->apu.wave_channel.wave_form[0] = gb->apu.wave_channel.wave_form[offset / 2];
gb->apu.wave_channel.wave_form[1] = gb->apu.wave_channel.wave_form[offset / 2 + 1];
}
else {
memcpy(gb->io_registers + GB_IO_WAV_START,
gb->io_registers + GB_IO_WAV_START + (offset & ~3),
4);
memcpy(gb->apu.wave_channel.wave_form,
gb->apu.wave_channel.wave_form + (offset & ~3) * 2,
8);
}
}
if (!gb->apu.is_active[GB_WAVE] && gb->apu.wave_channel.enable) {
gb->apu.wave_channel.current_sample_index = 0;
if (gb->apu.is_active[GB_WAVE] && gb->apu.wave_channel.sample_countdown == 0) {
gb->apu.wave_channel.current_sample_byte = gb->io_registers[GB_IO_WAV_START];
}
if (gb->apu.wave_channel.enable) {
gb->apu.is_active[GB_WAVE] = true;
update_sample(gb, GB_WAVE,
gb->apu.wave_channel.current_sample >> gb->apu.wave_channel.shift,
(gb->apu.wave_channel.current_sample_byte >> 4) >> gb->apu.wave_channel.shift,
0);
}
gb->apu.wave_channel.sample_countdown = (gb->apu.wave_channel.sample_length ^ 0x7FF) + 3;
gb->apu.wave_channel.current_sample_index = 0;
if (gb->apu.wave_channel.pulse_length == 0) {
gb->apu.wave_channel.pulse_length = 0x100;
gb->apu.wave_channel.length_enabled = false;
@ -1396,12 +1409,6 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
gb->apu.noise_channel.length_enabled = value & 0x40;
break;
}
default:
if (reg >= GB_IO_WAV_START && reg <= GB_IO_WAV_END) {
gb->apu.wave_channel.wave_form[(reg - GB_IO_WAV_START) * 2] = value >> 4;
gb->apu.wave_channel.wave_form[(reg - GB_IO_WAV_START) * 2 + 1] = value & 0xF;
}
}
gb->io_registers[reg] = value;
}

4
Core/apu.h
View File

@ -99,9 +99,9 @@ typedef struct
uint16_t sample_countdown; // in APU ticks (Reloaded from sample_length, xorred $7FF)
uint8_t current_sample_index;
uint8_t current_sample; // Current sample before shifting.
uint8_t current_sample_byte; // Current sample byte.
int8_t wave_form[32];
GB_PADDING(int8_t, wave_form)[32];
bool wave_form_just_read;
} wave_channel;

12
Core/debugger.c
View File

@ -1797,8 +1797,9 @@ static bool apu(GB_gameboy_t *gb, char *arguments, char *modifiers, const debugg
GB_log(gb, "\nCH3:\n");
GB_log(gb, " Wave:");
for (uint8_t i = 0; i < 32; i++) {
GB_log(gb, "%s%X", i%4?"":" ", gb->apu.wave_channel.wave_form[i]);
for (uint8_t i = 0; i < 16; i++) {
GB_log(gb, "%s%X", i % 2? "" : " ", gb->io_registers[GB_IO_WAV_START + i] >> 4);
GB_log(gb, "%s%X", i % 2? "" : " ", gb->io_registers[GB_IO_WAV_START + i] & 0xF);
}
GB_log(gb, "\n");
GB_log(gb, " Current position: %u\n", gb->apu.wave_channel.current_sample_index);
@ -1880,8 +1881,11 @@ static bool wave(GB_gameboy_t *gb, char *arguments, char *modifiers, const debug
for (int8_t cur_val = 0xf & mask; cur_val >= 0; cur_val -= shift_amount) {
for (uint8_t i = 0; i < 32; i++) {
if ((gb->apu.wave_channel.wave_form[i] & mask) == cur_val) {
GB_log(gb, "%X", gb->apu.wave_channel.wave_form[i]);
uint8_t sample = i & 1?
(gb->io_registers[GB_IO_WAV_START + i / 2] & 0xF) :
(gb->io_registers[GB_IO_WAV_START + i / 2] >> 4);
if ((sample & mask) == cur_val) {
GB_log(gb, "%X", sample);
}
else {
GB_log(gb, "%c", i % 4 == 2 ? '-' : ' ');

9
Core/gb.c
View File

@ -1536,18 +1536,13 @@ static void reset_ram(GB_gameboy_t *gb)
case GB_MODEL_SGB_PAL_NO_SFC: /* Unverified */
case GB_MODEL_SGB2:
case GB_MODEL_SGB2_NO_SFC: {
uint8_t temp;
for (unsigned i = 0; i < GB_IO_WAV_END - GB_IO_WAV_START; i++) {
if (i & 1) {
temp = GB_random() & GB_random() & GB_random();
gb->io_registers[GB_IO_WAV_START + i] = GB_random() & GB_random() & GB_random();
}
else {
temp = GB_random() | GB_random() | GB_random();
gb->io_registers[GB_IO_WAV_START + i] = GB_random() | GB_random() | GB_random();
}
gb->apu.wave_channel.wave_form[i * 2] = temp >> 4;
gb->apu.wave_channel.wave_form[i * 2 + 1] = temp & 0xF;
gb->io_registers[GB_IO_WAV_START + i] = temp;
}
break;
}