remove loop command from command stream

it is unused

papers/export-tech.md

@@ -99,7 +99,7 @@ hex | description
  d0 | UNUSED - placeholder used during optimization passes (3-byte nonce follows)
  d1 | no operation
  d2 | UNUSED
- d3 | loop (negative offset and count follow... both are 8-bit)
+ d3 | UNUSED
  d4 | UNUSED - call symbol (32-bit index follows; only used internally)
  d5 | call sub-block (32-bit address follows)
  d6 | note off + wait one tick

src/asm/6502/stream.s

@@ -176,6 +176,23 @@ fcsNoOpOneByte:
   jsr fcsReadNext
   rts
 
+fcsPan:
+  jsr fcsReadNext
+  sta chanPan,x
+  sta fcsArg0
+  jsr fcsReadNext
+  sta chanPan+1,x
+  sta fcsArg1
+  ldy #10
+  jsr fcsDispatchCmd
+  rts
+
+fcsOptPlaceholder:
+  jsr fcsReadNext
+  jsr fcsReadNext
+  jsr fcsReadNext
+  rts
+
 fcsNoOp:
   rts
 
@@ -211,7 +228,7 @@ fcsNoOp:
 ; $d0 fcsOptPlaceholder,
 ; $d1 fcsNoOp,
 ; $d2 fcsNoOp,
-; $d3 fcsLoop,
+; $d3 fcsNoOp,
 ; $d4 fcsNoOp,
 ; $d5 fcsCallI,
 ; $d6 fcsOffWait,

src/engine/cmdStream.cpp

@@ -220,23 +220,6 @@ bool DivCSPlayer::tick() {
           break;
         case 0xd1: // nop
           break;
-        case 0xd3: { // loop
-          unsigned char loopOff=stream.readC();
-          if (chan[i].loopCount>0) {
-            stream.readC();
-            if (--chan[i].loopCount) {
-              // jump
-              chan[i].readPos-=loopOff;
-              mustTell=false;
-            }
-          } else {
-            chan[i].loopCount=stream.readC();
-            // jump
-            chan[i].readPos-=loopOff;
-            mustTell=false;
-          }
-          break;
-        }
         case 0xd6: // note off + wait 1
           e->dispatchCmd(DivCommand(DIV_CMD_NOTE_OFF,i));
           chan[i].waitTicks=1;

src/engine/cmdStream.h

@@ -38,7 +38,7 @@ struct DivCSChannelState {
   int volume, volMax, volSpeed, volSpeedTarget;
   int vibratoDepth, vibratoRate, vibratoPos, vibratoRange, vibratoShape;
   int portaTarget, portaSpeed;
-  unsigned char arp, arpStage, arpTicks, loopCount;
+  unsigned char arp, arpStage, arpTicks;
 
   unsigned int callStack[DIV_MAX_CSSTACK];
   unsigned char callStackPos;
@@ -66,7 +66,6 @@ struct DivCSChannelState {
     arp(0),
     arpStage(0),
     arpTicks(0),
-    loopCount(0),
     callStackPos(0),
     tracePos(0) {
     for (int i=0; i<DIV_MAX_CSTRACE; i++) {

src/gui/csPlayer.cpp

@@ -131,9 +131,6 @@ String disasmCmd(unsigned char* buf, size_t bufLen, unsigned int addr, unsigned
     case 0xd1:
       return "nop";
       break;
-    case 0xd3:
-      return fmt::sprintf("loop (-%d), %d",(int)buf[addr+1],(int)buf[addr+2]);
-      break;
     case 0xd4:
       if (addr+2>=bufLen) return "???";
       return fmt::sprintf("callsym $%.4x",(int)(buf[addr+1]|(buf[addr+2]<<8)));