Improve Virtual Boy emulator (#2446)

src/engine/platform/sound/vsu.cpp

@@ -51,6 +51,8 @@ void VSU::Power(void)
  SweepControl = 0;
  SweepModCounter = 0;
  SweepModClockDivider = 1;
+ ModState = 0;
+ ModLock = 0;
 
  for(int ch = 0; ch < 6; ch++)
  {
@@ -62,7 +64,9 @@ void VSU::Power(void)
   RAMAddress[ch] = 0;
 
   EffFreq[ch] = 0;
-  Envelope[ch] = 0;
+  EnvelopeReload[ch] = 0;
+  EnvelopeValue[ch] = 0;
+  EnvelopeModMask[ch] = 0;
   WavePos[ch] = 0;
   FreqCounter[ch] = 1;
   IntervalCounter[ch] = 0;
@@ -100,6 +104,8 @@ void VSU::Write(int timestamp, unsigned int A, unsigned char V)
 
  Update(timestamp);
 
+ ModLock = 0;
+
  //printf("VSU Write: %d, %08x %02x\n", timestamp, A, V);
 
  if(A < 0x280)
@@ -133,7 +139,6 @@ void VSU::Write(int timestamp, unsigned int A, unsigned char V)
 
 	     if(V & 0x80)
 	     {
-	      EffFreq[ch] = Frequency[ch];
 	      if(ch == 5)
 	       FreqCounter[ch] = 10 * (2048 - EffFreq[ch]);
 	      else
@@ -146,6 +151,7 @@ void VSU::Write(int timestamp, unsigned int A, unsigned char V)
 	       SweepModCounter = (SweepControl >> 4) & 7;
                SweepModClockDivider = (SweepControl & 0x80) ? 8 : 1;
                ModWavePos = 0;
+               ModState = 0;
 	      }
 
 	      WavePos[ch] = 0;
@@ -153,8 +159,11 @@ void VSU::Write(int timestamp, unsigned int A, unsigned char V)
 	      if(ch == 5)	// Not sure if this is correct.
 	       lfsr = 1;
 
-	      //if(!(IntlControl[ch] & 0x80))
+        EnvelopeModMask[ch] = 0;
-	      // Envelope[ch] = (EnvControl[ch] >> 4) & 0xF;
+        if(!(EnvControl[ch] & 0x200) && (
+           (EnvelopeValue[ch] == 0 && !(EnvControl[ch] & 0x0008)) ||
+           (EnvelopeValue[ch] == 0xF && (EnvControl[ch] & 0x0008))))
+         EnvelopeModMask[ch] = 1;
 
 	      EffectsClockDivider[ch] = 4800;
 	      IntervalClockDivider[ch] = 4;
@@ -170,18 +179,24 @@ void VSU::Write(int timestamp, unsigned int A, unsigned char V)
              Frequency[ch] |= V << 0;
              EffFreq[ch] &= 0xFF00;
              EffFreq[ch] |= V << 0;
+             ModLock = 1;
 	     break;
 
    case 0x3: Frequency[ch] &= 0x00FF;
              Frequency[ch] |= (V & 0x7) << 8;
              EffFreq[ch] &= 0x00FF;
              EffFreq[ch] |= (V & 0x7) << 8;
+             ModLock = 2;
 	     break;
 
    case 0x4: EnvControl[ch] &= 0xFF00;
 	     EnvControl[ch] |= V << 0;
 
-	     Envelope[ch] = (V >> 4) & 0xF;
+	     EnvelopeReload[ch] = (V >> 4) & 0xF;
+	     EnvelopeValue[ch] = (V >> 4) & 0xF;
+
+       if(EnvelopeModMask[ch] == 1)
+        EnvelopeModMask[ch] = 2;
 	     break;
 
    case 0x5: EnvControl[ch] &= 0x00FF;
@@ -194,6 +209,12 @@ void VSU::Write(int timestamp, unsigned int A, unsigned char V)
 	     }
 	     else
 	      EnvControl[ch] |= (V & 0x03) << 8;
+
+       if(EnvelopeModMask[ch] == 0 && !(EnvControl[ch] & 0x200) && (
+          (EnvelopeValue[ch] == 0 && !(EnvControl[ch] & 0x0008)) ||
+          (EnvelopeValue[ch] == 0xF && (EnvControl[ch] & 0x0008))))
+        EnvelopeModMask[ch] = 1;
+       
 	     break;
 
    case 0x6: RAMAddress[ch] = V & 0xF;
@@ -228,14 +249,14 @@ inline void VSU::CalcCurrentOutput(int ch, int &left, int &right)
   else
    WD = WaveData[RAMAddress[ch]][WavePos[ch]];	// - 0x20;
  }
- l_ol = Envelope[ch] * LeftLevel[ch];
+ l_ol = EnvelopeValue[ch] * LeftLevel[ch];
  if(l_ol)
  {
   l_ol >>= 3;
   l_ol += 1;
  }
 
- r_ol = Envelope[ch] * RightLevel[ch];
+ r_ol = EnvelopeValue[ch] * RightLevel[ch];
  if(r_ol)
  {
   r_ol >>= 3;
@@ -355,23 +376,27 @@ void VSU::Update(int timestamp)
      {
       EnvelopeClockDivider[ch] += 4;
 
+      int new_envelope = EnvelopeValue[ch];
+      if(EnvelopeValue[ch] < 0xF && (EnvControl[ch] & 0x0008))
+       new_envelope++;
+      else if(EnvelopeValue[ch] > 0 && !(EnvControl[ch] & 0x0008))
+       new_envelope--;
+      else if((EnvControl[ch] & 0x200) && EnvelopeModMask[ch] != 2)
+       {
+        new_envelope = EnvelopeReload[ch];
+        EnvelopeModMask[ch] = 0;
+       }
+      else if(EnvelopeModMask[ch] == 0)
+       EnvelopeModMask[ch] = 1;
+
       if(EnvControl[ch] & 0x0100)	// Enveloping enabled?
       {
        EnvelopeCounter[ch]--;
        if(!EnvelopeCounter[ch])
        {
         EnvelopeCounter[ch] = (EnvControl[ch] & 0x7) + 1;
-
+        if(EnvelopeModMask[ch] == 0)
-        if(EnvControl[ch] & 0x0008)	// Grow
+         EnvelopeValue[ch] = new_envelope;
-        {
-         if(Envelope[ch] < 0xF || (EnvControl[ch] & 0x200))
-	  Envelope[ch] = (Envelope[ch] + 1) & 0xF;
-        }
-        else				// Decay
-        {
-         if(Envelope[ch] > 0 || (EnvControl[ch] & 0x200))
-          Envelope[ch] = (Envelope[ch] - 1) & 0xF;
-        }
        }
       }
 
@@ -380,6 +405,19 @@ void VSU::Update(int timestamp)
 
     if(ch == 4)
     {
+
+      // Calculate sweep early
+      int delta = EffFreq[ch] >> (SweepControl & 0x7);
+      int NewSweepFreq = EffFreq[ch] + ((SweepControl & 0x8) ? delta : -delta);
+
+      if(!(EnvControl[ch] & 0x1000))
+       {
+        if(NewSweepFreq < 0)
+         NewSweepFreq = 0;
+        else if(NewSweepFreq > 0x7FF)
+         IntlControl[ch] &= ~0x80;
+       }
+
      SweepModClockDivider--;
      while(SweepModClockDivider <= 0)
      {
@@ -396,30 +434,27 @@ void VSU::Update(int timestamp)
 
         if(EnvControl[ch] & 0x1000)        // Modulation
         {
-	 if(ModWavePos < 32 || (EnvControl[ch] & 0x2000))
+         if(ModState == 0 || (EnvControl[ch] & 0x2000))
-	 {
-          ModWavePos &= 0x1F;
-
           EffFreq[ch] = (Frequency[ch] + (signed char)ModData[ModWavePos]) & 0x7FF;
-	  ModWavePos++;
+         if(ModState == 1)
-	 }
+          ModState = 2;
-        }
-        else				// Sweep
-        {
-         int delta = EffFreq[ch] >> (SweepControl & 0x7);
-	 int NewFreq = EffFreq[ch] + ((SweepControl & 0x8) ? delta : -delta);
 
-	 //printf("Sweep(%d): Old: %d, New: %d\n", ch, EffFreq[ch], NewFreq);
+         // Hardware bug: writing to S5FQ* locks the relevant byte when modulating
-
+         if(ModLock == 1)
-         if(NewFreq < 0)
+          EffFreq[ch] = (EffFreq[ch] & 0x700) | (Frequency[ch] & 0xFF);
-          EffFreq[ch] = 0;
+         else if(ModLock == 2)
-         else if(NewFreq > 0x7FF)
+          EffFreq[ch] = (EffFreq[ch] & 0xFF) | (Frequency[ch] & 0x700);
-         {
-          //EffFreq[ch] = 0x7FF;
-	  IntlControl[ch] &= ~0x80;
         }
-         else
+        else if(ModState < 2)               // Sweep
-          EffFreq[ch] = NewFreq;
+        {
+          EffFreq[ch] = NewSweepFreq;
+        }
+
+        if(++ModWavePos >= 32)
+         {
+          if(ModState == 0)
+           ModState = 1;
+          ModWavePos = 0;
          }
        }
       }

src/engine/platform/sound/vsu.h

@@ -74,7 +74,8 @@ class VSU
  //
  //
  int EffFreq[6];
- int Envelope[6];
+ int EnvelopeValue[6];
+ int EnvelopeReload[6];
 
  int WavePos[6];
  int ModWavePos;
@@ -91,6 +92,10 @@ class VSU
  int EnvelopeClockDivider[6];
  int SweepModClockDivider;
 
+ int EnvelopeModMask[6];
+ int ModState;
+ int ModLock;
+
  int NoiseLatcherClockDivider;
  unsigned int NoiseLatcher;