AY: this sucks, part 1

src/engine/platform/ay.cpp

@@ -248,40 +248,74 @@ void DivPlatformAY8910::checkWrites() {
   }
 }
 
-void DivPlatformAY8910::acquire_mame(short** buf, size_t len) {
+void DivPlatformAY8910::acquire_mame(blip_buffer_t** bb, size_t len) {
   thread_local short ayBuf[3];
 
   for (int i=0; i<3; i++) {
     oscBuf[i]->begin(len);
   }
 
-  if (sunsoft) {
   for (size_t i=0; i<len; i++) {
-      runDAC();
+    int advance=len-i;
-      runTFX();
+    // heuristic
+    for (int j=0; j<3; j++) {
+      // tone counter
+      const int period=MAX(1,ay->m_tone[j].period)*(ay->m_step_mul<<1);
+      const int remain=period-ay->m_tone[j].count;
+      if (remain<advance) advance=remain;
+
+      // envelope
+      if (j<1) {
+        if (ay->m_envelope[j].holding==0) {
+          const int periodEnv=MAX(1,ay->m_envelope[j].period)*ay->m_env_step_mul;
+          const int remainEnv=periodEnv-ay->m_envelope[j].count;
+          if (remainEnv<advance) advance=remainEnv;
+        }
+      }
+    }
+    // noise
+    const int noisePeriod=((int)ay->noise_period())*ay->m_step_mul;
+    const int noiseRemain=noisePeriod-ay->m_count_noise;
+    if (noiseRemain<advance) advance=noiseRemain;
+
+    //runDAC();
+    //runTFX();
+
+    if (!writes.empty() || advance<1) advance=1;
     checkWrites();
 
-      ay->sound_stream_update(ayBuf,1);
+    ay->sound_stream_update(ayBuf,advance);
-      buf[0][i]=ayBuf[0];
+    i+=advance-1;
-      buf[1][i]=buf[0][i];
+
+    if (sunsoft) {
+      if (lastOut[0]!=ayBuf[0]) {
+        blip_add_delta(bb[0],i,ayBuf[0]-lastOut[0]);
+        blip_add_delta(bb[1],i,ayBuf[0]-lastOut[0]);
+        lastOut[0]=ayBuf[0];
+      }
 
       oscBuf[0]->putSample(i,CLAMP(sunsoftVolTable[31-(ay->lastIndx&31)]<<3,-32768,32767));
       oscBuf[1]->putSample(i,CLAMP(sunsoftVolTable[31-((ay->lastIndx>>5)&31)]<<3,-32768,32767));
       oscBuf[2]->putSample(i,CLAMP(sunsoftVolTable[31-((ay->lastIndx>>10)&31)]<<3,-32768,32767));
+    } else {
+      if (stereo) {
+        int out0=ayBuf[0]+ayBuf[1]+((ayBuf[2]*stereoSep)>>8);
+        int out1=((ayBuf[0]*stereoSep)>>8)+ayBuf[1]+ayBuf[2];
+        if (lastOut[0]!=out0) {
+          blip_add_delta(bb[0],i,out0-lastOut[0]);
+          lastOut[0]=out0;
+        }
+        if (lastOut[1]!=out1) {
+          blip_add_delta(bb[1],i,out1-lastOut[1]);
+          lastOut[1]=out1;
         }
       } else {
-    for (size_t i=0; i<len; i++) {
+        int out=ayBuf[0]+ayBuf[1]+ayBuf[2];
-      runDAC();
+        if (lastOut[0]!=out) {
-      runTFX();
+          blip_add_delta(bb[0],i,out-lastOut[0]);
-      checkWrites();
+          blip_add_delta(bb[1],i,out-lastOut[0]);
-
+          lastOut[0]=out;
-      ay->sound_stream_update(ayBuf,1);
+        }
-      if (stereo) {
-        buf[0][i]=ayBuf[0]+ayBuf[1]+((ayBuf[2]*stereoSep)>>8);
-        buf[1][i]=((ayBuf[0]*stereoSep)>>8)+ayBuf[1]+ayBuf[2];
-      } else {
-        buf[0][i]=ayBuf[0]+ayBuf[1]+ayBuf[2];
-        buf[1][i]=buf[0][i];
       }
 
       oscBuf[0]->putSample(i,ayBuf[0]<<2);
@@ -330,11 +364,14 @@ void DivPlatformAY8910::acquire_atomic(short** buf, size_t len) {
   }
 }
 
+void DivPlatformAY8910::acquireDirect(blip_buffer_t** bb, size_t len) {
+  if (selCore && !intellivision) return;
+  acquire_mame(bb,len);
+}
+
 void DivPlatformAY8910::acquire(short** buf, size_t len) {
   if (selCore && !intellivision) {
     acquire_atomic(buf,len);
-  } else {
-    acquire_mame(buf,len);
   }
 }
 
@@ -1011,6 +1048,8 @@ void DivPlatformAY8910::reset() {
   ayEnvSlideLow=0;
 
   delay=0;
+  lastOut[0]=0;
+  lastOut[1]=0;
 
   ioPortA=false;
   ioPortB=false;
@@ -1026,6 +1065,10 @@ bool DivPlatformAY8910::keyOffAffectsArp(int ch) {
   return true;
 }
 
+bool DivPlatformAY8910::hasAcquireDirect() {
+  return (!selCore || intellivision);
+}
+
 bool DivPlatformAY8910::getLegacyAlwaysSetVolume() {
   return false;
 }

src/engine/platform/ay.h

@@ -128,6 +128,7 @@ class DivPlatformAY8910: public DivDispatch {
     ssg_t ay_atomic;
 
     int delay;
+    int lastOut[2];
 
     bool extMode;
     unsigned int extClock;
@@ -149,7 +150,7 @@ class DivPlatformAY8910: public DivDispatch {
     void checkWrites();
     void updateOutSel(bool immediate=false);
 
-    void acquire_mame(short** buf, size_t len);
+    void acquire_mame(blip_buffer_t** bb, size_t len);
     void acquire_atomic(short** buf, size_t len);
   
     friend void putDispatchChip(void*,int);
@@ -160,6 +161,7 @@ class DivPlatformAY8910: public DivDispatch {
     void runTFX(int runRate=0);
     void setExtClockDiv(unsigned int eclk=COLOR_NTSC, unsigned char ediv=8);
     void acquire(short** buf, size_t len);
+    void acquireDirect(blip_buffer_t** bb, size_t len);
     void fillStream(std::vector<DivDelayedWrite>& stream, int sRate, size_t len);
     int dispatch(DivCommand c);
     void* getChanState(int chan);
@@ -177,6 +179,7 @@ class DivPlatformAY8910: public DivDispatch {
     void setFlags(const DivConfig& flags);
     int getOutputCount();
     bool keyOffAffectsArp(int ch);
+    bool hasAcquireDirect();
     DivMacroInt* getChanMacroInt(int ch);
     DivSamplePos getSamplePos(int ch);
     bool getLegacyAlwaysSetVolume();

src/engine/platform/sound/ay8910.cpp

@@ -1035,13 +1035,11 @@ void ay8910_device::ay8910_write_reg(int r, int v)
 //  sound_stream_update - handle a stream update
 //-------------------------------------------------
 
-void ay8910_device::sound_stream_update(short* outputs, int outLen)
+void ay8910_device::sound_stream_update(short* outputs, int advance)
 {
   tone_t *tone;
   envelope_t *envelope;
 
-	int samples = outLen;
-
   /* hack to prevent us from hanging when starting filtered outputs */
   if (!m_ready)
   {
@@ -1056,14 +1054,12 @@ void ay8910_device::sound_stream_update(short* outputs, int outLen)
   /* Note that this means that if both tone and noise are disabled, the output */
   /* is 1, not 0, and can be modulated changing the volume. */
 
-	/* buffering loop */
+  /* loop? kill the loop and optimize! */
-	for (int sampindex = 0; sampindex < samples; sampindex++)
-	{
   for (int chan = 0; chan < NUM_CHANNELS; chan++)
   {
     tone = &m_tone[chan];
     const int period = std::max<int>(1, tone->period) * (m_step_mul << 1);
-			tone->count += is_expanded_mode() ? 32 : ((m_feature & PSG_HAS_EXPANDED_MODE) ? 1 : 2);
+    tone->count += advance << (is_expanded_mode() ? 5 : ((m_feature & PSG_HAS_EXPANDED_MODE) ? 0 : 1));
                       if (tone->count>=period) {
                         tone->duty_cycle = (tone->duty_cycle - (tone->count/period)) & 0x1f;
                         tone->output = is_expanded_mode() ? BIT(duty_cycle[tone_duty(tone)], tone->duty_cycle) : BIT(tone->duty_cycle, 0);
@@ -1072,12 +1068,13 @@ void ay8910_device::sound_stream_update(short* outputs, int outLen)
   }
 
   const int period_noise = (int)(noise_period()) * m_step_mul;
-		if ((++m_count_noise) >= period_noise)
+  m_count_noise+=advance;
+  while (m_count_noise >= period_noise)
   {
     /* toggle the prescaler output. Noise is no different to
      * channels.
      */
-			m_count_noise = 0;
+    m_count_noise -= period_noise;
     m_prescale_noise = (m_prescale_noise + 1) & ((m_feature & PSG_HAS_EXPANDED_MODE) ? 3 : 1);
 
     if (is_expanded_mode()) // AY8930 noise generator rate is twice? compares as compatibility mode
@@ -1110,15 +1107,17 @@ void ay8910_device::sound_stream_update(short* outputs, int outLen)
   }
 
   /* update envelope */
-		for (int chan = 0; chan < NUM_CHANNELS; chan++)
+  // who cares about env 1/2 on 8910
+  for (int chan = 0; chan < (is_expanded_mode() ? NUM_CHANNELS : 1); chan++)
   {
     envelope = &m_envelope[chan];
     if (envelope->holding == 0)
     {
       const int period = std::max<int>(1, envelope->period) * m_env_step_mul;
-				if ((++envelope->count) >= period)
+      envelope->count += advance;
+      if (envelope->count >= period)
       {
-					envelope->count = 0;
+        envelope->count %= period;
         envelope->step--;
 
         /* check envelope current position */
@@ -1195,7 +1194,6 @@ void ay8910_device::sound_stream_update(short* outputs, int outLen)
   {
     outputs[0]=mix_3D();
   }
-	}
 }
 
 void ay8910_device::build_mixer_table()

src/engine/platform/sound/ay8910.h

@@ -164,7 +164,7 @@ public:
 	unsigned char ay8910_read_ym();
 	void ay8910_reset_ym();
 
-private:
+public:
 	static constexpr int NUM_CHANNELS = 3;
   device_type chip_type;