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Implement most of channels 1 and 2

This commit is contained in:
Jeffrey Pfau 2013-10-18 23:12:14 -07:00
parent 79d483d002
commit 003a537dc7
2 changed files with 138 additions and 12 deletions
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124
src/gba/gba-audio.c
View File

@ -8,8 +8,11 @@
const unsigned GBA_AUDIO_SAMPLES = 512;
const unsigned GBA_AUDIO_FIFO_SIZE = 8 * sizeof(int32_t);
#define SWEEP_CYCLES (GBA_ARM7TDMI_FREQUENCY / 128)
static int32_t _updateSquareChannel(struct GBAAudioSquareControl* envelope, int duty);
static void _updateEnvelope(struct GBAAudioEnvelope* envelope);
static void _updateSweep(struct GBAAudioChannel1* ch);
static int32_t _updateChannel1(struct GBAAudioChannel1* ch);
static int32_t _updateChannel2(struct GBAAudioChannel2* ch);
static int32_t _updateChannel3(struct GBAAudioChannel3* ch);
@ -23,7 +26,12 @@ void GBAAudioInit(struct GBAAudio* audio) {
audio->nextCh3 = 0;
audio->nextCh4 = 0;
audio->ch1.envelope.nextStep = INT_MAX;
audio->ch1.control.nextStep = 0;
audio->ch1.nextSweep = INT_MAX;
audio->ch1.sample = 0;
audio->ch2.envelope.nextStep = INT_MAX;
audio->ch2.control.nextStep = 0;
audio->ch2.sample = 0;
audio->ch4.sample = 0;
audio->ch4.envelope.nextStep = INT_MAX;
audio->eventDiff = 0;
@ -65,6 +73,19 @@ int32_t GBAAudioProcessEvents(struct GBAAudio* audio, int32_t cycles) {
audio->ch1.envelope.nextStep -= audio->eventDiff;
if (audio->ch1.envelope.nextStep <= 0) {
_updateEnvelope(&audio->ch1.envelope);
if (audio->ch1.envelope.nextStep < audio->nextEvent) {
audio->nextEvent = audio->ch1.envelope.nextStep;
}
}
}
if (audio->ch1.nextSweep != INT_MAX) {
audio->ch1.nextSweep -= audio->eventDiff;
if (audio->ch1.nextSweep <= 0) {
_updateSweep(&audio->ch1);
if (audio->ch1.nextSweep < audio->nextEvent) {
audio->nextEvent = audio->ch1.nextSweep;
}
}
}
@ -72,6 +93,9 @@ int32_t GBAAudioProcessEvents(struct GBAAudio* audio, int32_t cycles) {
audio->ch2.envelope.nextStep -= audio->eventDiff;
if (audio->ch2.envelope.nextStep <= 0) {
_updateEnvelope(&audio->ch2.envelope);
if (audio->ch2.envelope.nextStep < audio->nextEvent) {
audio->nextEvent = audio->ch2.envelope.nextStep;
}
}
}
@ -80,21 +104,30 @@ int32_t GBAAudioProcessEvents(struct GBAAudio* audio, int32_t cycles) {
if (audio->ch4.envelope.nextStep <= 0) {
_updateEnvelope(&audio->ch4.envelope);
if (audio->ch4.envelope.nextStep < audio->nextEvent) {
audio->nextEvent = audio->nextCh4;
audio->nextEvent = audio->ch4.envelope.nextStep;
}
}
}
if ((audio->ch1Right || audio->ch1Left) && audio->nextCh1 <= 0) {
audio->nextCh1 += _updateChannel1(&audio->ch1);
if (audio->nextCh1 < audio->nextEvent) {
audio->nextEvent = audio->nextCh1;
}
}
if ((audio->ch2Right || audio->ch2Left) && audio->nextCh2 <= 0) {
audio->nextCh2 += _updateChannel2(&audio->ch2);
if (audio->nextCh2 < audio->nextEvent) {
audio->nextEvent = audio->nextCh2;
}
}
if ((audio->ch3Right || audio->ch3Left) && audio->nextCh3 <= 0) {
audio->nextCh3 += _updateChannel3(&audio->ch3);
if (audio->nextCh3 < audio->nextEvent) {
audio->nextEvent = audio->nextCh3;
}
}
if ((audio->ch4Right || audio->ch4Left) && audio->nextCh4 <= 0) {
@ -135,6 +168,9 @@ void GBAAudioScheduleFifoDma(struct GBAAudio* audio, int number, struct GBADMA*
void GBAAudioWriteSOUND1CNT_LO(struct GBAAudio* audio, uint16_t value) {
audio->ch1.sweep.packed = value;
if (!audio->ch1.sweep.time) {
audio->ch1.nextSweep = INT_MAX;
}
}
void GBAAudioWriteSOUND1CNT_HI(struct GBAAudio* audio, uint16_t value) {
@ -148,6 +184,19 @@ void GBAAudioWriteSOUND1CNT_HI(struct GBAAudio* audio, uint16_t value) {
void GBAAudioWriteSOUND1CNT_X(struct GBAAudio* audio, uint16_t value) {
audio->ch1.control.packed = value;
audio->ch1.control.currentFrequency = audio->ch1.control.frequency;
if (audio->ch1.control.restart) {
if (audio->ch1.sweep.time) {
audio->ch1.nextSweep = audio->ch1.sweep.time * SWEEP_CYCLES;
}
audio->ch1.envelope.currentVolume = audio->ch1.envelope.initialVolume;
if (audio->ch1.envelope.stepTime) {
audio->ch1.envelope.nextStep = 0;
} else {
audio->ch1.envelope.nextStep = INT_MAX;
}
audio->nextCh1 = 0;
}
}
void GBAAudioWriteSOUND2CNT_LO(struct GBAAudio* audio, uint16_t value) {
@ -161,6 +210,16 @@ void GBAAudioWriteSOUND2CNT_LO(struct GBAAudio* audio, uint16_t value) {
void GBAAudioWriteSOUND2CNT_HI(struct GBAAudio* audio, uint16_t value) {
audio->ch2.control.packed = value;
audio->ch2.control.currentFrequency = audio->ch2.control.frequency;
if (audio->ch2.control.restart) {
audio->ch2.envelope.currentVolume = audio->ch2.envelope.initialVolume;
if (audio->ch2.envelope.stepTime) {
audio->ch2.envelope.nextStep = 0;
} else {
audio->ch2.envelope.nextStep = INT_MAX;
}
audio->nextCh2 = 0;
}
}
void GBAAudioWriteSOUND3CNT_LO(struct GBAAudio* audio, uint16_t value) {
@ -255,6 +314,24 @@ void GBAAudioSampleFIFO(struct GBAAudio* audio, int fifoId) {
CircleBufferRead8(&channel->fifo, &channel->sample);
}
static int32_t _updateSquareChannel(struct GBAAudioSquareControl* control, int duty) {
control->hi = !control->hi;
int period = 16 * (2048 - control->currentFrequency);
switch (duty) {
case 0:
return control->hi ? period : period * 7;
case 1:
return control->hi ? period * 2 : period * 6;
case 2:
return period * 4;
case 3:
return control->hi ? period * 6 : period * 2;
default:
// This should never be hit
return period * 4;
}
}
static void _updateEnvelope(struct GBAAudioEnvelope* envelope) {
if (envelope->direction) {
++envelope->currentVolume;
@ -272,12 +349,37 @@ static void _updateEnvelope(struct GBAAudioEnvelope* envelope) {
}
}
static void _updateSweep(struct GBAAudioChannel1* ch) {
if (ch->sweep.direction) {
int currentFrequency = ch->control.currentFrequency;
currentFrequency -= currentFrequency >> ch->sweep.shift;
if (currentFrequency >= 0) {
ch->control.currentFrequency = currentFrequency;
}
} else {
int currentFrequency = ch->control.currentFrequency;
currentFrequency += currentFrequency >> ch->sweep.shift;
if (currentFrequency < 2048) {
ch->control.currentFrequency = currentFrequency;
} else {
// TODO: Stop playing
}
}
ch->nextSweep += ch->sweep.time * SWEEP_CYCLES;
}
static int32_t _updateChannel1(struct GBAAudioChannel1* ch) {
return INT_MAX / 4;
int timing = _updateSquareChannel(&ch->control, ch->envelope.duty);
ch->sample = ch->control.hi * 0x10 - 0x8;
ch->sample *= ch->envelope.currentVolume;
return timing;
}
static int32_t _updateChannel2(struct GBAAudioChannel2* ch) {
return INT_MAX / 4;
int timing = _updateSquareChannel(&ch->control, ch->envelope.duty);
ch->sample = ch->control.hi * 0x10 - 0x8;
ch->sample *= ch->envelope.currentVolume;
return timing;
}
static int32_t _updateChannel3(struct GBAAudioChannel3* ch) {
@ -301,6 +403,22 @@ static void _sample(struct GBAAudio* audio) {
int32_t sampleRight = 0;
int psgShift = 2 - audio->volume;
if (audio->ch1Left) {
sampleLeft += audio->ch1.sample >> psgShift;
}
if (audio->ch1Right) {
sampleRight += audio->ch1.sample >> psgShift;
}
if (audio->ch2Left) {
sampleLeft += audio->ch2.sample >> psgShift;
}
if (audio->ch2Right) {
sampleRight += audio->ch2.sample >> psgShift;
}
if (audio->ch4Left) {
sampleLeft += audio->ch4.sample >> psgShift;
}

26
src/gba/gba-audio.h
View File

@ -25,14 +25,19 @@ struct GBAAudioEnvelope {
int32_t nextStep;
};
union GBAAudioSquareControl {
struct {
unsigned frequency : 11;
unsigned : 3;
unsigned stop : 1;
unsigned restart : 1;
struct GBAAudioSquareControl {
union {
struct {
unsigned frequency : 11;
unsigned : 3;
unsigned stop : 1;
unsigned restart : 1;
};
uint16_t packed;
};
uint16_t packed;
int hi;
int currentFrequency;
int32_t nextStep;
};
struct GBAAudioChannel1 {
@ -45,14 +50,17 @@ struct GBAAudioChannel1 {
};
uint16_t packed;
} sweep;
int32_t nextSweep;
struct GBAAudioEnvelope envelope;
union GBAAudioSquareControl control;
struct GBAAudioSquareControl control;
int8_t sample;
};
struct GBAAudioChannel2 {
struct GBAAudioEnvelope envelope;
union GBAAudioSquareControl control;
struct GBAAudioSquareControl control;
int8_t sample;
};
struct GBAAudioChannel3 {