ShuriZma
/
bsnes
mirror of https://github.com/bsnes-emu/bsnes.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Added channel 1 and 2, fixed accuracy issues with channel 3

This commit is contained in:
Lior Halphon 2017-07-27 23:11:33 +03:00
parent 2936f7fa57
commit d65c2247e5
4 changed files with 221 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

203
Core/apu.c
View File

@ -6,6 +6,13 @@
#define likely(x) __builtin_expect((x), 1)
#define unlikely(x) __builtin_expect((x), 0)
static const uint8_t duties[] = {
0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 1, 1,
0, 0, 0, 0, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 0, 0,
};
static void refresh_channel(GB_gameboy_t *gb, unsigned index, unsigned cycles_offset)
{
unsigned multiplier = gb->apu_output.cycles_since_render + cycles_offset - gb->apu_output.last_update[index];
@ -65,23 +72,119 @@ static void render(GB_gameboy_t *gb)
void GB_apu_div_event(GB_gameboy_t *gb)
{
if (gb->apu.is_active[GB_WAVE] && gb->apu.wave_channel.length_enabled) {
if (gb->apu.wave_channel.pulse_length) {
gb->apu.wave_channel.pulse_length--;
if (!gb->apu.global_enable) return;
for (unsigned i = GB_SQUARE_2 + 1; i--;) {
if (gb->apu.square_channels[i].length_enabled) {
if (gb->apu.square_channels[i].pulse_length) {
if (!--gb->apu.square_channels[i].pulse_length) {
gb->apu.is_active[i] = false;
update_sample(gb, i, 0, 0);
}
}
}
else {
gb->apu.is_active[GB_WAVE] = false;
gb->apu.wave_channel.current_sample = 0;
update_sample(gb, GB_WAVE, 0, 0);
uint8_t nrx2 = gb->io_registers[i == GB_SQUARE_1? GB_IO_NR12 : GB_IO_NR22];
if (gb->apu.square_channels[i].volume_countdown) {
if (!--gb->apu.square_channels[i].volume_countdown) {
if ((nrx2 & 8) && gb->apu.square_channels[i].current_volume < 0xF) {
gb->apu.square_channels[i].current_volume++;
}
else if (!(nrx2 & 8) && gb->apu.square_channels[i].current_volume > 0) {
gb->apu.square_channels[i].current_volume--;
}
gb->apu.square_channels[i].volume_countdown = (nrx2 & 7) * 8;
uint8_t duty = gb->io_registers[i == GB_SQUARE_1? GB_IO_NR11 :GB_IO_NR21] >> 6;
update_sample(gb, i,
duties[gb->apu.square_channels[i].current_sample_index + duty * 8]?
gb->apu.square_channels[i].current_volume : 0,
0);
}
}
}
gb->apu.square_sweep_div++;
if ((gb->apu.square_sweep_div & 3) == 3) {
if (gb->apu.square_sweep_countdown) {
if (!--gb->apu.square_sweep_countdown) {
gb->apu.square_channels[GB_SQUARE_1].sample_length ^= 0x7FF;
uint16_t delta = gb->apu.square_channels[GB_SQUARE_1].sample_length >> (gb->io_registers[GB_IO_NR10] & 7);
if (gb->io_registers[GB_IO_NR10] & 8) {
gb->apu.square_channels[GB_SQUARE_1].sample_length -= delta;
}
else {
gb->apu.square_channels[GB_SQUARE_1].sample_length += delta;
}
if (gb->apu.square_channels[GB_SQUARE_1].sample_length > 0x7f0) {
gb->apu.square_sweep_stop_countdown = 0x13 - gb->apu.square_carry;
}
gb->apu.square_channels[GB_SQUARE_1].sample_length ^= 0x7FF;
gb->apu.square_channels[GB_SQUARE_1].sample_length &= 0x7FF;
gb->apu.square_sweep_countdown = ((gb->io_registers[GB_IO_NR10] >> 4) & 7);
}
}
}
if (gb->apu.wave_channel.length_enabled) {
if (gb->apu.wave_channel.pulse_length) {
if (!--gb->apu.wave_channel.pulse_length) {
gb->apu.is_active[GB_WAVE] = false;
gb->apu.wave_channel.current_sample = 0;
update_sample(gb, GB_WAVE, 0, 0);
}
}
}
}
void GB_apu_run(GB_gameboy_t *gb, uint8_t cycles)
void GB_apu_run(GB_gameboy_t *gb)
{
/* Convert 4MHZ to 2MHz. cycles is always even. */
cycles >>= 1;
/* Convert 4MHZ to 2MHz. apu_cycles is always even. */
uint8_t cycles = gb->apu.apu_cycles >> 1;
gb->apu.apu_cycles = 0;
if (!cycles) return;
/* To align the square signal to 1MHz */
gb->apu.square_carry ^= cycles & 1;
if (gb->apu.square_sweep_stop_countdown) {
if (gb->apu.square_sweep_stop_countdown > cycles) {
gb->apu.square_sweep_stop_countdown -= cycles;
}
else {
gb->apu.square_sweep_stop_countdown = 0;
gb->apu.is_active[GB_SQUARE_1] = false;
update_sample(gb, GB_SQUARE_1, 0, 0);
}
}
for (unsigned i = GB_SQUARE_2 + 1; i--;) {
if (gb->apu.is_active[i]) {
uint8_t cycles_left = cycles;
while (unlikely(cycles_left > gb->apu.square_channels[i].sample_countdown)) {
cycles_left -= gb->apu.square_channels[i].sample_countdown + 1;
gb->apu.square_channels[i].sample_countdown = gb->apu.square_channels[i].sample_length * 2 + 1;
gb->apu.square_channels[i].current_sample_index++;
gb->apu.square_channels[i].current_sample_index &= 0x7;
uint8_t duty = gb->io_registers[i == GB_SQUARE_1? GB_IO_NR11 :GB_IO_NR21] >> 6;
update_sample(gb, i,
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;
}
}
}
gb->apu.wave_channel.wave_form_just_read = false;
if (gb->apu.is_active[GB_WAVE]) {
@ -154,6 +257,7 @@ void GB_apu_init(GB_gameboy_t *gb)
gb->apu.left_enabled[i] = gb->apu.right_enabled[i] = true;
}
gb->apu.wave_channel.sample_length = 0x7FF;
gb->apu.square_carry = 1;
}
uint8_t GB_apu_read(GB_gameboy_t *gb, uint8_t reg)
@ -210,8 +314,7 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
}
gb->io_registers[reg] = value;
switch (reg) {
/* Globals */
case GB_IO_NR50:
@ -237,6 +340,77 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
}
break;
case GB_IO_NR10:
gb->apu.square_sweep_countdown = ((value >> 4) & 7);
break;
case GB_IO_NR11:
case GB_IO_NR21: {
unsigned index = reg == GB_IO_NR21? GB_SQUARE_2: GB_SQUARE_1;
gb->apu.square_channels[index].pulse_length = (0x40 - (value & 0x3f)) * 2 - 1;
break;
}
case GB_IO_NR12:
case GB_IO_NR22: {
/* TODO: What happens when changing bits 0-2 after triggering? */
if ((value & 0xF8) == 0) {
/* According to Blargg's test ROM this should disable the channel instantly
TODO: verify how "instant" the change is using PCM12*/
unsigned index = reg == GB_IO_NR22? GB_SQUARE_2: GB_SQUARE_1;
update_sample(gb, index, 0, 0);
gb->apu.is_active[index] = false;
}
break;
}
case GB_IO_NR13:
case GB_IO_NR23: {
unsigned index = reg == GB_IO_NR23? GB_SQUARE_2: GB_SQUARE_1;
gb->apu.square_channels[index].sample_length &= ~0xFF;
gb->apu.square_channels[index].sample_length |= (~value) & 0xFF;
break;
}
/* Square channels */
case GB_IO_NR14:
case GB_IO_NR24: {
unsigned index = reg == GB_IO_NR24? GB_SQUARE_2: GB_SQUARE_1;
gb->apu.square_channels[index].length_enabled = value & 0x40;
gb->apu.square_channels[index].sample_length &= 0xFF;
gb->apu.square_channels[index].sample_length |= ((~value) & 7) << 8;
if (value & 0x80) {
gb->apu.square_channels[index].current_sample_index = 7;
if (!gb->apu.is_active[index]) {
gb->apu.square_channels[index].sample_countdown = gb->apu.square_channels[index].sample_length * 2 + 6 - gb->apu.square_carry;
}
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 * 2 + 4 - gb->apu.square_carry;
}
else {
gb->apu.square_channels[index].sample_countdown = gb->apu.square_carry;
gb->apu.square_channels[index].current_sample_index = 0;
}
}
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) * 8;
if ((gb->io_registers[index == GB_SQUARE_1 ? GB_IO_NR12 : GB_IO_NR22] & 0xF8) != 0) {
gb->apu.is_active[index] = true;
}
if (gb->apu.square_channels[index].pulse_length == 0) {
gb->apu.square_channels[index].pulse_length = 0x7F;
}
/* Note that we don't change the sample just yet! This was verified on hardware. */
}
break;
}
/* Wave channel */
case GB_IO_NR30:
gb->apu.wave_channel.enable = value & 0x80;
@ -247,6 +421,7 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
}
break;
case GB_IO_NR31:
gb->apu.wave_channel.pulse_length = (0x100 - value) * 2 - 1;
break;
case GB_IO_NR32:
gb->apu.wave_channel.shift = (uint8_t[]){4, 0, 1, 2}[(value >> 5) & 3];
@ -283,9 +458,11 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
}
}
gb->apu.is_active[GB_WAVE] = true;
gb->apu.wave_channel.pulse_length = (~gb->io_registers[GB_IO_NR31]) * 2;
gb->apu.wave_channel.sample_countdown = gb->apu.wave_channel.sample_length + 3;
gb->apu.wave_channel.current_sample_index = 0;
if (gb->apu.wave_channel.pulse_length == 0) {
gb->apu.wave_channel.pulse_length = 0x1FF;
}
/* Note that we don't change the sample just yet! This was verified on hardware. */
}
break;

25
Core/apu.h
View File

@ -31,15 +31,36 @@ enum GB_CHANNELS {
typedef struct
{
bool global_enable;
uint8_t apu_cycles;
uint8_t samples[GB_N_CHANNELS];
bool left_enabled[GB_N_CHANNELS];
bool right_enabled[GB_N_CHANNELS];
bool is_active[GB_N_CHANNELS];
uint8_t square_carry; // The square channels tick at 1MHz instead of 2,
// so we need a carry to divide the signal
uint8_t square_sweep_div; // The DIV-APU ticks are divided by 4 to handle tone sweeping
uint8_t square_sweep_countdown; // In 128Hz
uint8_t square_sweep_stop_countdown; // In 2 MHz
struct {
uint16_t pulse_length; // Reloaded from NRX1 (xorred), in DIV ticks
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
uint16_t sample_length; // Reloaded from NRX3, NRX4, in APU ticks
bool length_enabled; // NRX4
} square_channels[2];
struct {
bool enable; // NR30
uint8_t pulse_length; // Reloaded from NR31 (xorred), in DIV ticks
uint16_t pulse_length; // Reloaded from NR31 (xorred), in DIV ticks
uint8_t shift; // NR32
uint16_t sample_length; // NR33, NR34, in APU ticks
bool length_enabled; // NR34
@ -82,7 +103,7 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value);
uint8_t GB_apu_read(GB_gameboy_t *gb, uint8_t reg);
void GB_apu_div_event(GB_gameboy_t *gb);
void GB_apu_init(GB_gameboy_t *gb);
void GB_apu_run(GB_gameboy_t *gb, uint8_t cycles);
void GB_apu_run(GB_gameboy_t *gb);
#endif
#endif /* apu_h */

5
Core/gb.h
View File

@ -65,6 +65,7 @@ enum {
GB_IO_NR12 = 0x12, // Channel 1 Volume Envelope (R/W)
GB_IO_NR13 = 0x13, // Channel 1 Frequency lo (Write Only)
GB_IO_NR14 = 0x14, // Channel 1 Frequency hi (R/W)
/* NR20 does not exist */
GB_IO_NR21 = 0x16, // Channel 2 Sound Length/Wave Pattern Duty (R/W)
GB_IO_NR22 = 0x17, // Channel 2 Volume Envelope (R/W)
GB_IO_NR23 = 0x18, // Channel 2 Frequency lo data (W)
@ -74,9 +75,7 @@ enum {
GB_IO_NR32 = 0x1c, // Channel 3 Select output level (R/W)
GB_IO_NR33 = 0x1d, // Channel 3 Frequency's lower data (W)
GB_IO_NR34 = 0x1e, // Channel 3 Frequency's higher data (R/W)
/* Missing */
/* NR40 does not exist */
GB_IO_NR41 = 0x20, // Channel 4 Sound Length (R/W)
GB_IO_NR42 = 0x21, // Channel 4 Volume Envelope (R/W)
GB_IO_NR43 = 0x22, // Channel 4 Polynomial Counter (R/W)

10
Core/timing.c
View File

@ -97,7 +97,10 @@ void GB_advance_cycles(GB_gameboy_t *gb, uint8_t cycles)
advance_tima_state_machine(gb);
for (int i = 0; i < cycles; i += 4) {
/* This is a bit tricky. The DIV and APU are tightly coupled, but DIV is affected
by the speed boost while the APU is not */
GB_set_internal_div_counter(gb, gb->div_cycles + 4);
gb->apu.apu_cycles += 4 >> gb->cgb_double_speed;
}
if (cycles > 4) {
@ -127,9 +130,7 @@ void GB_advance_cycles(GB_gameboy_t *gb, uint8_t cycles)
gb->debugger_ticks += cycles;
if (gb->cgb_double_speed) {
cycles >>=1;
}
cycles >>= gb->cgb_double_speed;
// Not affected by speed boost
gb->hdma_cycles += cycles;
@ -139,7 +140,7 @@ void GB_advance_cycles(GB_gameboy_t *gb, uint8_t cycles)
gb->cycles_since_last_sync += cycles;
GB_dma_run(gb);
GB_hdma_run(gb);
GB_apu_run(gb, cycles);
GB_apu_run(gb);
GB_display_run(gb, cycles);
GB_ir_run(gb);
}
@ -171,6 +172,7 @@ void GB_set_internal_div_counter(GB_gameboy_t *gb, uint32_t value)
increase_tima(gb);
}
if (counter_overflow_check(gb->div_cycles, value, gb->cgb_double_speed? 0x4000 : 0x2000)) {
GB_apu_run(gb);
GB_apu_div_event(gb);
}
gb->div_cycles = value;