-lots of changes to try and reduce total cpu load, notably reduced ho…

…w often the main loop runs, how the ppu rendering works (using some optimizations from nestopia) and massively improving fds audio code to now take much less cpu and being much closer to real hardware

apu.c

@@ -160,6 +160,9 @@ extern uint16_t cpu_dmc_dma_addr;
 
 #define M_2_PI 6.28318530717958647692
 
+extern bool fdsMasterEnable;
+extern uint32_t vrc7CycleTimer;
+
 extern bool nesPAL;
 void apuInitBufs()
 {
@@ -189,7 +192,9 @@ void apuInitBufs()
 	//convert to 32bit int for calcs later
 	hpVal = (int32_t)((rc / (rc + dt))*32768.0);
 #endif
-	apuBufSize = apuFrequency/60*2;
+	//just have something larger than 1 frame
+	//to hold changing data size
+	apuBufSize = apuFrequency/30*2;
 #if AUDIO_FLOAT
 	apuBufSizeBytes = apuBufSize*sizeof(float);
 	apuOutBuf = (float*)malloc(apuBufSizeBytes);
@@ -298,6 +303,8 @@ static void apuChangeMode()
 		modeCurCtr = nesPAL ? 8315 : 7459;
 }
 
+static uint8_t vrc7Clock = 1;
+
 void apuClockTimers()
 {
 	if(p1freqCtr)
@@ -378,6 +385,19 @@ void apuClockTimers()
 		cpu_dmc_dma_addr = dmcCurAddr;
 		dmcCurLen--;
 	}
+
+	if(fdsEnabled)
+		fdsAudioMasterUpdate();
+	if(vrc7enabled)
+	{
+		if(vrc7Clock == vrc7CycleTimer)
+		{
+			vrc7AudioCycle();
+			vrc7Clock = 1;
+		}
+		else
+			vrc7Clock++;
+	}
 }
 
 #if AUDIO_FLOAT
@@ -391,32 +411,8 @@ extern bool emuSkipVsync, emuSkipFrame;
 
 static float ampVol[7] = { 3.0f, 2.0f, 1.5f, 1.2f, 1.0f, 0.85f, 0.75f };
 
-bool apuCycle()
+void apuCycle()
 {
-	if(curBufPos == apuBufSize)
-	{
-		int updateRes = audioUpdate();
-		if(updateRes == 0)
-		{
-			emuSkipFrame = false;
-			emuSkipVsync = false;
-			return false;
-		}
-		if(updateRes > 6)
-		{
-			emuSkipVsync = true;
-			emuSkipFrame = true;
-		}
-		else
-		{
-			emuSkipFrame = false;
-			if(updateRes > 2)
-				emuSkipVsync = true;
-			else
-				emuSkipVsync = false;
-		}
-		curBufPos = 0;
-	}
 	if(p1LengthCtr && (APU_IO_Reg[0x15] & P1_ENABLE))
 	{
 		if(!p1Sweep.mute && freq1 >= 8 && freq1 < 0x7FF)
@@ -536,7 +532,6 @@ bool apuCycle()
 #endif
 	apuOutBuf[curBufPos+1] = apuOutBuf[curBufPos];
 	curBufPos+=2;
-	return true;
 }
 
 void doEnvelopeLogic(envelope_t *env)
@@ -893,10 +888,39 @@ uint8_t *apuGetBuf()
 
 uint32_t apuGetBufSize()
 {
-	return apuBufSizeBytes;
+#if AUDIO_FLOAT
+	return curBufPos*sizeof(float);
+#else
+	return curBufPos*sizeof(int16_t);
+#endif
 }
 
 uint32_t apuGetFrequency()
 {
 	return apuFrequency;
 }
+
+static bool waitForRefill = false;
+bool apuUpdate()
+{
+	int updateRes = audioUpdate();
+	//printf("%i\n",updateRes);
+	if(updateRes == 0)
+	{
+		emuSkipFrame = false;
+		waitForRefill = false;
+		return false;
+	}
+	if(waitForRefill && updateRes < 2)
+	{
+		waitForRefill = false;
+		emuSkipFrame = false;
+	}
+	else if(!waitForRefill && updateRes > 2)
+	{
+		emuSkipFrame = true;
+		waitForRefill = true;
+	}
+	curBufPos = 0;
+	return true;
+}

apu.h

@@ -8,12 +8,12 @@
 #ifndef _apu_h_
 #define _apu_h_
 
-#define NUM_BUFFERS 10
+#define NUM_BUFFERS 4
 
 void apuInitBufs();
 void apuDeinitBufs();
 void apuInit();
-bool apuCycle();
+void apuCycle();
 void apuClockTimers();
 void apuWriteDMCBuf(uint8_t val);
 uint8_t *apuGetBuf();
@@ -22,6 +22,7 @@ uint32_t apuGetFrequency();
 void apuSet8(uint8_t reg, uint8_t val);
 uint8_t apuGet8(uint8_t reg);
 void apuLenCycle();
+bool apuUpdate();
 
 
 typedef struct _envelope_t {