implement arp speed and arp tick

src/engine/engine.h

@@ -11,7 +11,7 @@ struct DivChannelState {
   int volume, volSpeed, cut, rowDelay, volMax;
   int vibratoDepth, vibratoRate, vibratoPos, vibratoDir;
   int tremoloDepth, tremoloRate, tremoloPos;
-  unsigned char arp, arpStage;
+  unsigned char arp, arpStage, arpTicks;
   bool doNote, legato;
 
   DivChannelState():
@@ -32,6 +32,7 @@ struct DivChannelState {
     tremoloPos(0),
     arp(0),
     arpStage(-1),
+    arpTicks(1),
     doNote(false), legato(false) {}
 };
 

src/engine/platform/genesis.cpp

@@ -331,6 +331,8 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
     case DIV_CMD_GET_VOLMAX:
       return 127;
       break;
+    case DIV_CMD_PRE_PORTA:
+      break;
     default:
       printf("WARNING: unimplemented command %d\n",c.cmd);
       break;

src/engine/playback.cpp

@@ -218,6 +218,9 @@ void DivEngine::processRow(int i, bool afterDelay) {
         chan[i].rowDelay=effectVal+1;
         break;
       
+      case 0xe0: // arp speed
+        song.arpLen=effectVal;
+        break;
       case 0xe1: // portamento up
         chan[i].portaNote=chan[i].note+(effectVal&15);
         chan[i].portaSpeed=(effectVal>>4)*4;
@@ -239,6 +242,9 @@ void DivEngine::processRow(int i, bool afterDelay) {
       case 0xec: // delayed note cut
         chan[i].cut=effectVal+1;
         break;
+      case 0xee: // external command
+        printf("\x1b[1;36m%d: extern command %d\x1b[m\n",i,effectVal);
+        break;
     }
   }
 
@@ -393,6 +399,8 @@ void DivEngine::nextTick() {
       }
     }
     if (chan[i].arp!=0 && chan[i].portaSpeed<1) {
+      if (--chan[i].arpTicks<1) {
+        chan[i].arpTicks=song.arpLen;
         chan[i].arpStage++;
         if (chan[i].arpStage>2) chan[i].arpStage=0;
         switch (chan[i].arpStage) {
@@ -408,6 +416,7 @@ void DivEngine::nextTick() {
         }
       }
     }
+  }
 
   // system tick
   dispatch->tick();