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SPU: Emulate voice decode buffers. #13497

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b1cc005
SPU: clang-format mixer.cpp
Ziemas Nov 5, 2025
77dd916
SPU: Remove unused voice struct members
Ziemas Oct 26, 2025
8328b4e
SPU: Emulate voice decode buffers
Ziemas Nov 5, 2025
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1 change: 0 additions & 1 deletion pcsx2/SPU2/Debug.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -200,7 +200,6 @@ void SPU2::DoFullDump()
fprintf(dump, " - Sound Start Address: %x\n", Cores[c].Voices[v].StartA);
fprintf(dump, " - Next Data Address: %x\n", Cores[c].Voices[v].NextA);
fprintf(dump, " - Play Status: %s\n", (Cores[c].Voices[v].ADSR.Phase > 0) ? "Playing" : "Not Playing");
fprintf(dump, " - Block Sample: %d\n", Cores[c].Voices[v].SCurrent);
}
fprintf(dump, "#### END OF DUMP.\n\n");
}
Expand Down
213 changes: 98 additions & 115 deletions pcsx2/SPU2/Mixer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -89,55 +89,13 @@ int g_counter_cache_ignores = 0;
#define XAFLAG_LOOP (1ul << 1)
#define XAFLAG_LOOP_START (1ul << 2)

static __forceinline s32 GetNextDataBuffered(V_Core& thiscore, uint voiceidx)
static __forceinline void GetNextDataBuffered(V_Core& thiscore, uint voiceidx)
{
V_Voice& vc(thiscore.Voices[voiceidx]);

if ((vc.SCurrent & 3) == 0)
if (vc.SBuffer == nullptr)
{
IncrementNextA(thiscore, voiceidx);

if ((vc.NextA & 7) == 0) // vc.SCurrent == 24 equivalent
{
if (vc.LoopFlags & XAFLAG_LOOP_END)
{
thiscore.Regs.ENDX |= (1 << voiceidx);
vc.NextA = vc.LoopStartA | 1;
if (!(vc.LoopFlags & XAFLAG_LOOP))
{
vc.Stop();

if (IsDevBuild)
{
if (SPU2::MsgVoiceOff())
SPU2::ConLog("* SPU2: Voice Off by EndPoint: %d \n", voiceidx);
}
}
}
else
vc.NextA++; // no, don't IncrementNextA here. We haven't read the header yet.
}
}

if (vc.SCurrent == 28)
{
vc.SCurrent = 0;

// We'll need the loop flags and buffer pointers regardless of cache status:

for (int i = 0; i < 2; i++)
if (Cores[i].IRQEnable && Cores[i].IRQA == (vc.NextA & 0xFFFF8))
SetIrqCall(i);

s16* memptr = GetMemPtr(vc.NextA & 0xFFFF8);
vc.LoopFlags = *memptr >> 8; // grab loop flags from the upper byte.

if ((vc.LoopFlags & XAFLAG_LOOP_START) && !vc.LoopMode)
{
vc.LoopStartA = vc.NextA & 0xFFFF8;
}

const int cacheIdx = vc.NextA / pcm_WordsPerBlock;
const int cacheIdx = (vc.NextA & 0xFFFF8) / pcm_WordsPerBlock;
PcmCacheEntry& cacheLine = pcm_cache_data[cacheIdx];
vc.SBuffer = cacheLine.Sampledata;

Expand Down Expand Up @@ -172,46 +130,18 @@ static __forceinline s32 GetNextDataBuffered(V_Core& thiscore, uint voiceidx)
g_counter_cache_misses++;
}

XA_decode_block(vc.SBuffer, memptr, vc.Prev1, vc.Prev2);
}
}

return vc.SBuffer[vc.SCurrent++];
}

static __forceinline void GetNextDataDummy(V_Core& thiscore, uint voiceidx)
{
V_Voice& vc(thiscore.Voices[voiceidx]);

IncrementNextA(thiscore, voiceidx);

if ((vc.NextA & 7) == 0) // vc.SCurrent == 24 equivalent
{
if (vc.LoopFlags & XAFLAG_LOOP_END)
{
thiscore.Regs.ENDX |= (1 << voiceidx);
vc.NextA = vc.LoopStartA | 1;
s16* memptr = GetMemPtr(vc.NextA & 0xFFFF8);
XA_decode_block(vc.SBuffer, memptr, vc.Prev1, vc.Prev2);
}
else
vc.NextA++; // no, don't IncrementNextA here. We haven't read the header yet.
}

if (vc.SCurrent == 28)
// Get the sample index for NextA, we have to subtract 1 to ignore the loop header
int sampleIdx = ((vc.NextA % pcm_WordsPerBlock) - 1) * 4;
for (int i = 0; i < 4; i++)
{
for (int i = 0; i < 2; i++)
if (Cores[i].IRQEnable && Cores[i].IRQA == (vc.NextA & 0xFFFF8))
SetIrqCall(i);

vc.LoopFlags = *GetMemPtr(vc.NextA & 0xFFFF8) >> 8; // grab loop flags from the upper byte.

if ((vc.LoopFlags & XAFLAG_LOOP_START) && !vc.LoopMode)
vc.LoopStartA = vc.NextA & 0xFFFF8;

vc.SCurrent = 0;
vc.DecodeFifo[(vc.DecPosWrite + i) % 32] = vc.SBuffer[sampleIdx + i];
}

vc.SP -= 0x1000 * (4 - (vc.SCurrent & 3));
vc.SCurrent += 4 - (vc.SCurrent & 3);
}

/////////////////////////////////////////////////////////////////////////////////////////
Expand All @@ -237,6 +167,69 @@ static __forceinline StereoOut32 ApplyVolume(const StereoOut32& data, const V_Vo
ApplyVolume(data.Right, volume.Right.Value));
}

static __forceinline void UpdateBlockHeader(V_Core& thiscore, uint voiceidx)
{
V_Voice& vc(thiscore.Voices[voiceidx]);

for (int i = 0; i < 2; i++)
if (Cores[i].IRQEnable && Cores[i].IRQA == (vc.NextA & 0xFFFF8))
SetIrqCall(i);

s16* memptr = GetMemPtr(vc.NextA & 0xFFFF8);
vc.LoopFlags = *memptr >> 8; // grab loop flags from the upper byte.

if ((vc.LoopFlags & XAFLAG_LOOP_START) && !vc.LoopMode)
{
vc.LoopStartA = vc.NextA & 0xFFFF8;
}
}

static __forceinline void DecodeSamples(uint coreidx, uint voiceidx)
{
V_Core& thiscore(Cores[coreidx]);
V_Voice& vc(thiscore.Voices[voiceidx]);

// Update the block header on every audio frame
UpdateBlockHeader(thiscore, voiceidx);

// When a voice is started at 0 pitch, NAX quickly advances to SSA + 5
// So that would mean the decode buffer holds around 12 samples
if (((int)(vc.DecPosWrite - vc.DecPosRead)) > 12) {
// Sufficient data buffered
return;
}

if (vc.ADSR.Phase > V_ADSR::PHASE_STOPPED)
{
GetNextDataBuffered(thiscore, voiceidx);
}

vc.DecPosWrite += 4;

IncrementNextA(thiscore, voiceidx);
if ((vc.NextA & 7) == 0)
{
if (vc.LoopFlags & XAFLAG_LOOP_END)
{
thiscore.Regs.ENDX |= (1 << voiceidx);
vc.NextA = vc.LoopStartA;
if (!(vc.LoopFlags & XAFLAG_LOOP))
{
vc.Stop();

if (IsDevBuild)
{
if (SPU2::MsgVoiceOff())
SPU2::ConLog("* SPU2: Voice Off by EndPoint: %d \n", voiceidx);
}
}
}

IncrementNextA(thiscore, voiceidx);
vc.SBuffer = nullptr;
}
}

static void __forceinline UpdatePitch(uint coreidx, uint voiceidx)
{
V_Voice& vc(Cores[coreidx].Voices[voiceidx]);
Expand Down Expand Up @@ -278,33 +271,27 @@ static __forceinline void CalculateADSR(V_Core& thiscore, uint voiceidx)
pxAssume(vc.ADSR.Value >= 0); // ADSR should never be negative...
}

__forceinline static s32 GaussianInterpolate(s32 pv4, s32 pv3, s32 pv2, s32 pv1, s32 i)
static __forceinline void ConsumeSamples(V_Core& thiscore, uint voiceidx)
{
s32 out = 0;
out = (interpTable[i][0] * pv4) >> 15;
out += (interpTable[i][1] * pv3) >> 15;
out += (interpTable[i][2] * pv2) >> 15;
out += (interpTable[i][3] * pv1) >> 15;
V_Voice& vc(thiscore.Voices[voiceidx]);

return out;
int consumed = vc.SP >> 12;
vc.SP &= 0xfff;
vc.DecPosRead += consumed;
}

static __forceinline s32 GetVoiceValues(V_Core& thiscore, uint voiceidx)
{
V_Voice& vc(thiscore.Voices[voiceidx]);

while (vc.SP >= 0)
{
vc.PV4 = vc.PV3;
vc.PV3 = vc.PV2;
vc.PV2 = vc.PV1;
vc.PV1 = GetNextDataBuffered(thiscore, voiceidx);
vc.SP -= 0x1000;
}

const s32 mu = vc.SP + 0x1000;
int phase = (vc.SP & 0x0ff0) >> 4;
s32 out = 0;
out += (interpTable[phase][0] * vc.DecodeFifo[(vc.DecPosRead + 0) % 32]) >> 15;
out += (interpTable[phase][1] * vc.DecodeFifo[(vc.DecPosRead + 1) % 32]) >> 15;
out += (interpTable[phase][2] * vc.DecodeFifo[(vc.DecPosRead + 2) % 32]) >> 15;
out += (interpTable[phase][3] * vc.DecodeFifo[(vc.DecPosRead + 3) % 32]) >> 15;

return GaussianInterpolate(vc.PV4, vc.PV3, vc.PV2, vc.PV1, (mu & 0x0ff0) >> 4);
return out;
}

// This is Dr. Hell's noise algorithm as implemented in pcsxr
Expand Down Expand Up @@ -382,21 +369,13 @@ static __forceinline StereoOut32 MixVoice(uint coreidx, uint voiceidx)
V_Core& thiscore(Cores[coreidx]);
V_Voice& vc(thiscore.Voices[voiceidx]);

// If this assertion fails, it mans SCurrent is being corrupted somewhere, or is not initialized
// properly. Invalid values in SCurrent will cause errant IRQs and corrupted audio.
pxAssertMsg((vc.SCurrent <= 28) && (vc.SCurrent != 0), "Current sample should always range from 1->28");

// Most games don't use much volume slide effects. So only call the UpdateVolume
// methods when needed by checking the flag outside the method here...
// (Note: Ys 6 : Ark of Nephistm uses these effects)

vc.Volume.Update();

// SPU2 Note: The spu2 continues to process voices for eternity, always, so we
// have to run through all the motions of updating the voice regardless of it's
// audible status. Otherwise IRQs might not trigger and emulation might fail.

UpdatePitch(coreidx, voiceidx);
DecodeSamples(coreidx, voiceidx);

StereoOut32 voiceOut(0, 0);
s32 Value = 0;
Expand All @@ -419,11 +398,14 @@ static __forceinline StereoOut32 MixVoice(uint coreidx, uint voiceidx)

voiceOut = ApplyVolume(StereoOut32(Value, Value), vc.Volume);
}
else
{
while (vc.SP >= 0)
GetNextDataDummy(thiscore, voiceidx); // Dummy is enough
}

// SPU2 Note: The spu2 continues to process voices for eternity, always, so we
// have to run through all the motions of updating the voice regardless of it's
// audible status. Otherwise IRQs might not trigger and emulation might fail.

UpdatePitch(coreidx, voiceidx);

ConsumeSamples(thiscore, voiceidx);

// Write-back of raw voice data (post ADSR applied)
if (voiceidx == 1)
Expand Down Expand Up @@ -533,7 +515,8 @@ StereoOut32 V_Core::Mix(const VoiceMixSet& inVoices, const StereoOut32& Input, c
return TD + ApplyVolume(RV, FxVol);
}

static StereoOut32 DCFilter(StereoOut32 input) {
static StereoOut32 DCFilter(StereoOut32 input)
{
// A simple DC blocking high-pass filter
// Implementation from http://peabody.sapp.org/class/dmp2/lab/dcblock/
// The magic number 0x7f5c is ceil(INT16_MAX * 0.995)
Expand Down Expand Up @@ -634,9 +617,9 @@ __forceinline void spu2Mix()
if (SPU2::MsgCache())
{
SPU2::ConLog(" * SPU2 > CacheStats > Hits: %d Misses: %d Ignores: %d\n",
g_counter_cache_hits,
g_counter_cache_misses,
g_counter_cache_ignores);
g_counter_cache_hits,
g_counter_cache_misses,
g_counter_cache_ignores);
}

g_counter_cache_hits =
Expand Down
21 changes: 4 additions & 17 deletions pcsx2/SPU2/defs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -256,29 +256,16 @@ struct V_Voice
// Sample pointer (19:12 bit fixed point)
s32 SP;

// Sample pointer for Cubic Interpolation
// Cubic interpolation mixes a sample behind Linear, so that it
// can have sample data to either side of the end points from which
// to extrapolate. This SP represents that late sample position.
s32 SPc;

// Previous sample values - used for interpolation
// Inverted order of these members to match the access order in the
// code (might improve cache hits).
s32 PV4;
s32 PV3;
s32 PV2;
s32 PV1;

// Last outputted audio value, used for voice modulation.
s32 OutX;
s32 NextCrest; // temp value for Crest calculation

// SBuffer now points directly to an ADPCM cache entry.
s16* SBuffer;

// sample position within the current decoded packet.
s32 SCurrent;
// Each voice has a buffer of decoded samples
s32 DecodeFifo[32];
u32 DecPosWrite;
u32 DecPosRead;

// it takes a few ticks for voices to start on the real SPU2?
void Start();
Expand Down
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