wip

pkg/gba/apu.go

@@ -12,6 +12,12 @@ import (
 var waveSamples byte
 var wavePosition byte
 
+var waveRAM [0x20]byte
+
+func isWaveRAM(addr uint32) bool {
+	return addr >= 0x04000090 && addr <= 0x0400009f
+}
+
 const (
 	CPU_FREQ_HZ              = 16777216
 	SND_FREQUENCY            = 32768
@@ -22,10 +28,6 @@ const (
 	SAMPLE_TIME      float64 = 1.0 / 32768
 )
 
-const (
-	CH_LEN = 1 << 14
-)
-
 const (
 	PSG_MAX = 0x7f
 	PSG_MIN = -0x80
@@ -96,9 +98,6 @@ func (g *GBA) squareSample(ch int) int8 {
 	if !util.Bit(cntx, ch) {
 		return 0
 	}
-	if !(ch == 0 || ch == 1) {
-		return 0
-	}
 
 	toneAddr := uint32(ram.SOUND1CNT_H)
 	if ch == 1 {
@@ -138,8 +137,8 @@ func (g *GBA) squareSample(ch int) int8 {
 		if g.apu.chans[0].sweepTime >= sweepInterval {
 			g.apu.chans[0].sweepTime -= sweepInterval
 			sweepShift := byte(g._getRAM(ram.SOUND1CNT_L) & 0b111)
-			if sweepShift > 0 {
-				disp := uint32(freqHz >> sweepShift)
+			if sweepShift != 0 {
+				disp := freqHz >> sweepShift
 				if !util.Bit(g._getRAM(ram.SOUND1CNT_L), 3) {
 					freqHz += disp
 				} else {
@@ -200,9 +199,15 @@ func (g *GBA) squareSample(ch int) int8 {
 	}
 
 	if g.apu.chans[ch].phase {
-		return int8((float64(envelope) / 15) * PSG_MAX)
+		return int8(float64(envelope) * PSG_MAX / 15)
 	}
-	return int8((float64(envelope) / 15) * PSG_MIN)
+	return int8(float64(envelope) * PSG_MIN / 15)
+}
+
+func (g *GBA) enableSoundChan(ch int) {
+	cntx := byte(g._getRAM(ram.SOUNDCNT_X))
+	cntx = cntx | (1 << ch)
+	g._setRAM8(ram.SOUNDCNT_X, cntx)
 }
 
 func (g *GBA) disableSoundChan(ch int) {
@@ -231,7 +236,7 @@ func (g *GBA) waveSample() int8 {
 	cycleSamples := SND_FREQUENCY / frequency
 
 	// Length reached check (if so, just disable the channel and return silence)
-	if util.Bit(cntx, 14) {
+	if util.Bit(uint16(g._getRAM(ram.SOUND3CNT_X)), 14) {
 		g.apu.chans[2].lengthTime += SAMPLE_TIME
 		if g.apu.chans[2].lengthTime >= length {
 			g.disableSoundChan(2)
@@ -278,21 +283,20 @@ func (g *GBA) waveSample() int8 {
 }
 
 func (g *GBA) noiseSample() int8 {
-	cntx := g._getRAM(ram.SOUNDCNT_X)
-	if !util.Bit(cntx, 3) {
+	if !util.Bit(g._getRAM(ram.SOUNDCNT_X), 3) {
 		return 0
 	}
 
-	cnth := g._getRAM(ram.SOUND4CNT_H)
+	cnth := g._getRAM(ram.SOUND4CNT_H) // ctrl
 
 	// Actual frequency in Hertz
 	freqDiv, freqRsh := float64(cnth&0x7), float64((cnth>>4)&0xf)
 	if freqDiv == 0 {
-		freqDiv = 2
+		freqDiv = 1 / 2
 	}
-	frequency := (524288 * freqDiv) / math.Pow(2, freqRsh+1)
+	frequency := (524288 / freqDiv) / math.Pow(2, freqRsh+1)
 
-	cntl := g._getRAM(ram.SOUND4CNT_L)
+	cntl := g._getRAM(ram.SOUND4CNT_L) // env
 	// Full length of the generated wave (if enabled) in seconds
 	soundLen := cntl & 0x3f
 	length := (64 - float64(soundLen)) / 256
@@ -385,11 +389,11 @@ var stream []byte
 
 func (g *GBA) soundMix() {
 	for i := 0; i < len(sndBuffer); i += 4 {
-		stream[i+0] = byte(sndBuffer[sndCurPlay&BUFF_SAMPLES_MSK] << 6)
-		stream[i+1] = byte(sndBuffer[sndCurPlay&BUFF_SAMPLES_MSK]>>8) << 6
+		snd := sndBuffer[sndCurPlay&BUFF_SAMPLES_MSK] << 6
+		stream[i+0], stream[i+1] = byte(snd), byte(snd>>8)
 		sndCurPlay++
-		stream[i+2] = byte(sndBuffer[sndCurPlay&BUFF_SAMPLES_MSK] << 6)
-		stream[i+3] = byte(sndBuffer[sndCurPlay&BUFF_SAMPLES_MSK]>>8) << 6
+		snd = sndBuffer[sndCurPlay&BUFF_SAMPLES_MSK] << 6
+		stream[i+2], stream[i+3] = byte(snd), byte(snd>>8)
 		sndCurPlay++
 	}
 
@@ -410,7 +414,7 @@ func (g *GBA) fifoACopy() {
 
 	for i := uint32(0); i < 4; i++ {
 		fifoA[fifoALen] = int8(g._getRAM(ram.FIFO_A + i))
-		i++
+		fifoALen++
 	}
 }
 func (g *GBA) fifoBCopy() {
@@ -421,7 +425,7 @@ func (g *GBA) fifoBCopy() {
 
 	for i := uint32(0); i < 4; i++ {
 		fifoB[fifoBLen] = int8(g._getRAM(ram.FIFO_B + i))
-		i++
+		fifoBLen++
 	}
 }
 
@@ -478,7 +482,7 @@ func (g *GBA) soundClock(cycles uint32) {
 
 	sampPcmL, sampPcmR := int16(0), int16(0)
 
-	cnth := uint16(g._getRAM(ram.SOUNDCNT_H))
+	cnth := uint16(g._getRAM(ram.SOUNDCNT_H)) // snd_pcm_vol
 	sampCh4, sampCh5 := (int16(fifoASamp)<<1)>>^(cnth&4), (int16(fifoBSamp)<<1)>>^(cnth&8)
 
 	// Left
@@ -501,7 +505,7 @@ func (g *GBA) soundClock(cycles uint32) {
 		sampCh := [4]int16{int16(g.squareSample(0)), int16(g.squareSample(1)), int16(g.waveSample()), int16(g.noiseSample())}
 		sampPsgL, sampPsgR := int32(0), int32(0)
 
-		cntl := uint16(g._getRAM(ram.SOUNDCNT_L))
+		cntl := uint16(g._getRAM(ram.SOUNDCNT_L)) // snd_psg_vol
 		for i := 0; i < 4; i++ {
 			if util.Bit(cntl, 12+i) {
 				sampPsgL = int32(g.clip(sampPsgL + int32(sampCh[i])))
@@ -527,3 +531,29 @@ func (g *GBA) soundClock(cycles uint32) {
 		sndCycles -= SAMP_CYCLES
 	}
 }
+
+func (g *GBA) resetSoundChan(ch int, enable bool) {
+	if enable {
+		g.apu.chans[ch] = &SoundChan{
+			phase:      false,
+			samples:    0,
+			lengthTime: 0,
+			sweepTime:  0,
+			envTime:    0,
+		}
+
+		if ch == 2 {
+			g.waveReset()
+		}
+
+		if ch == 3 {
+			if util.Bit(g._getRAM(ram.SOUND4CNT_H), 3) {
+				g.apu.chans[3].lfsr = 0x007f
+			} else {
+				g.apu.chans[3].lfsr = 0x7fff
+			}
+		}
+
+		g.enableSoundChan(ch)
+	}
+}

pkg/gba/io.go

@@ -12,6 +12,10 @@ func (g *GBA) _getRAM(addr uint32) uint32 {
 	switch {
 	case gpu.IsIO(addr):
 		return util.LE32(g.GPU.IO[(addr - 0x0400_0000):])
+	case isWaveRAM(addr):
+		bank := (g._getRAM(ram.SOUND3CNT_L) >> 2) & 0x10
+		idx := (bank ^ 0x10) | (addr & 0xf)
+		return util.LE32(waveRAM[idx:])
 	case isDMA0IO(addr):
 		return g.dma[0].get(addr - 0x0400_00b0)
 	case isDMA1IO(addr):
@@ -96,6 +100,10 @@ func (g *GBA) _setRAM8(addr uint32, b byte) {
 	switch {
 	case gpu.IsIO(addr):
 		g.GPU.IO[addr-0x0400_0000] = b
+	case isWaveRAM(addr):
+		bank := (g._getRAM(ram.SOUND3CNT_L) >> 2) & 0x10
+		idx := (bank ^ 0x10) | (addr & 0xf)
+		waveRAM[idx] = b
 	case isDMA0IO(addr):
 		if g.dma[0].set(addr-0x0400_00b0, b) {
 			g.dmaTransfer(dmaImmediate)