From c766f9871977cd2b3ad594eafc5c334667da02c3 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Tue, 18 May 2021 02:53:59 -0500
Subject: [PATCH] implement arp speed and arp tick

---
 src/engine/engine.h             |  3 ++-
 src/engine/platform/genesis.cpp |  2 ++
 src/engine/playback.cpp         | 33 +++++++++++++++++++++------------
 3 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/src/engine/engine.h b/src/engine/engine.h
index 29aea64b3..2d0b63605 100644
--- a/src/engine/engine.h
+++ b/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) {}
 };
 
diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index 1b2fb87fb..d5e838639 100644
--- a/src/engine/platform/genesis.cpp
+++ b/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;
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 28f3c8eba..f376d6cfe 100644
--- a/src/engine/playback.cpp
+++ b/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;
     }
   }
 
@@ -393,18 +399,21 @@ void DivEngine::nextTick() {
       }
     }
     if (chan[i].arp!=0 && chan[i].portaSpeed<1) {
-      chan[i].arpStage++;
-      if (chan[i].arpStage>2) chan[i].arpStage=0;
-      switch (chan[i].arpStage) {
-        case 0:
-          dispatch->dispatch(DivCommand(DIV_CMD_LEGATO,i,chan[i].note));
-          break;
-        case 1:
-          dispatch->dispatch(DivCommand(DIV_CMD_LEGATO,i,chan[i].note+(chan[i].arp>>4)));
-          break;
-        case 2:
-          dispatch->dispatch(DivCommand(DIV_CMD_LEGATO,i,chan[i].note+(chan[i].arp&15)));
-          break;
+      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) {
+          case 0:
+            dispatch->dispatch(DivCommand(DIV_CMD_LEGATO,i,chan[i].note));
+            break;
+          case 1:
+            dispatch->dispatch(DivCommand(DIV_CMD_LEGATO,i,chan[i].note+(chan[i].arp>>4)));
+            break;
+          case 2:
+            dispatch->dispatch(DivCommand(DIV_CMD_LEGATO,i,chan[i].note+(chan[i].arp&15)));
+            break;
+        }
       }
     }
   }