diff --git a/src/engine/dispatch.h b/src/engine/dispatch.h
index f9815449..0b400547 100644
--- a/src/engine/dispatch.h
+++ b/src/engine/dispatch.h
@@ -15,15 +15,23 @@ enum DivDispatchCmds {
 
 struct DivCommand {
   DivDispatchCmds cmd;
-  unsigned char chan, value;
-  DivCommand(DivDispatchCmds c, unsigned char ch, unsigned char val):
+  unsigned char chan;
+  int value, value2;
+  DivCommand(DivDispatchCmds c, unsigned char ch, int val, int val2):
     cmd(c),
     chan(ch),
-    value(val) {}
+    value(val),
+    value2(val2) {}
+  DivCommand(DivDispatchCmds c, unsigned char ch, int val):
+    cmd(c),
+    chan(ch),
+    value(val),
+    value2(0) {}
   DivCommand(DivDispatchCmds c, unsigned char ch):
     cmd(c),
     chan(ch),
-    value(0) {}
+    value(0),
+    value2(0) {}
 };
 
 struct DivDelayedCommand {
diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index cfe62682..016ba75a 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -4,6 +4,7 @@
 #include "../audio/sdl.h"
 #include "platform/genesis.h"
 #include "platform/dummy.h"
+#include <math.h>
 #include <zlib.h>
 
 void process(void* u, float** in, float** out, int inChans, int outChans, unsigned int size) {
@@ -662,6 +663,10 @@ bool DivEngine::init() {
   bbOut[0]=new short[got.bufsize];
   bbOut[1]=new short[got.bufsize];
 
+  for (int i=0; i<60; i++) {
+    vibTable[i]=127*sin(((double)i/60.0)*(2*M_PI));
+  }
+
   switch (song.system) {
     case DIV_SYSTEM_GENESIS:
       dispatch=new DivPlatformGenesis;
diff --git a/src/engine/engine.h b/src/engine/engine.h
index b72ca532..babe2b7f 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -9,8 +9,9 @@ struct DivChannelState {
   std::vector<DivDelayedCommand> delayed;
   int note, pitch, portaSpeed, portaNote;
   int volume, volSpeed;
-  int vibratoDepth, vibratoRate;
-  int tremoloDepth, tremoloRate;
+  int vibratoDepth, vibratoRate, vibratoPos;
+  int tremoloDepth, tremoloRate, tremoloPos;
+  bool doNote;
 
   DivChannelState():
     note(-1),
@@ -21,8 +22,11 @@ struct DivChannelState {
     volSpeed(0),
     vibratoDepth(0),
     vibratoRate(0),
+    vibratoPos(0),
     tremoloDepth(0),
-    tremoloRate(0) {}
+    tremoloRate(0),
+    tremoloPos(0),
+    doNote(false) {}
 };
 
 class DivEngine {
@@ -36,6 +40,8 @@ class DivEngine {
   int changeOrd, changePos;
   DivChannelState chan[17];
 
+  short vibTable[60];
+
   blip_buffer_t* bb[2];
   short temp[2], prevSample[2];
   short* bbOut[2];
diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index 3ed84d5d..2821ec15 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -160,7 +160,8 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
         rWrite(chanOffs[c.chan]+0xb0,(ins->fm.alg&7)|(ins->fm.fb<<3));
         rWrite(chanOffs[c.chan]+0xb4,(chan[c.chan].pan<<6)|(ins->fm.fms&7)|((ins->fm.ams&3)<<4));
       }
-      chan[c.chan].freq=644.0f*pow(2.0f,((float)c.value/12.0f));
+      chan[c.chan].baseFreq=644.0f*pow(2.0f,((float)c.value/12.0f));
+      chan[c.chan].freq=(chan[c.chan].baseFreq*(2048+chan[c.chan].pitch))>>11;
       chan[c.chan].freqChanged=true;
       chan[c.chan].keyOn=true;
       chan[c.chan].active=true;
@@ -206,6 +207,33 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
       rWrite(chanOffs[c.chan]+0xb4,(chan[c.chan].pan<<6)|(ins->fm.fms&7)|((ins->fm.ams&3)<<4));
       break;
     }
+    case DIV_CMD_PITCH: {
+      chan[c.chan].pitch=c.value;
+      chan[c.chan].freq=(chan[c.chan].baseFreq*(2048+chan[c.chan].pitch))>>11;
+      chan[c.chan].freqChanged=true;
+      break;
+    }
+    case DIV_CMD_NOTE_PORTA: {
+      int destFreq=644.0f*pow(2.0f,((float)c.value2/12.0f));
+      bool return2=false;
+      if (destFreq>chan[c.chan].baseFreq) {
+        chan[c.chan].baseFreq=(chan[c.chan].baseFreq*(960+c.value))/960;
+        if (chan[c.chan].baseFreq>=destFreq) {
+          chan[c.chan].baseFreq=destFreq;
+          return2=true;
+        }
+      } else {
+        chan[c.chan].baseFreq=(chan[c.chan].baseFreq*(960-c.value))/960;
+        if (chan[c.chan].baseFreq<=destFreq) {
+          chan[c.chan].baseFreq=destFreq;
+          return2=true;
+        }
+      }
+      chan[c.chan].freq=(chan[c.chan].baseFreq*(2048+chan[c.chan].pitch))>>11;
+      chan[c.chan].freqChanged=true;
+      if (return2) return 2;
+      break;
+    }
     case DIV_CMD_SAMPLE_MODE: {
       if (c.chan==5) {
         dacMode=c.value;
diff --git a/src/engine/platform/genesis.h b/src/engine/platform/genesis.h
index c932f924..f8d07988 100644
--- a/src/engine/platform/genesis.h
+++ b/src/engine/platform/genesis.h
@@ -5,13 +5,13 @@
 class DivPlatformGenesis: public DivDispatch {
   struct Channel {
     unsigned char freqH, freqL;
-    int freq;
+    int freq, baseFreq, pitch;
     unsigned char ins;
     signed char konCycles;
     bool active, insChanged, freqChanged, keyOn, keyOff;
     signed char vol;
     unsigned char pan;
-    Channel(): freqH(0), freqL(0), freq(0), ins(0), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), vol(0), pan(3) {}
+    Channel(): freqH(0), freqL(0), freq(0), baseFreq(0), pitch(0), ins(0), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), vol(0), pan(3) {}
   };
   Channel chan[10];
   struct QueuedWrite {
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 685dd90e..1330c349 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -107,7 +107,7 @@ void DivEngine::nextRow() {
       dispatch->dispatch(DivCommand(DIV_CMD_NOTE_OFF,i));
     } else if (!(pat->data[curRow][0]==0 && pat->data[curRow][1]==0)) {
       chan[i].note=pat->data[curRow][0]+pat->data[curRow][1]*12;
-      dispatch->dispatch(DivCommand(DIV_CMD_NOTE_ON,i,chan[i].note));
+      chan[i].doNote=true;
     }
 
     // volume
@@ -118,8 +118,8 @@ void DivEngine::nextRow() {
 
     // effects
     for (int j=0; j<song.pat[i]->effectRows; j++) {
-      unsigned char effect=pat->data[curRow][4+(j<<1)];
-      unsigned char effectVal=pat->data[curRow][5+(j<<1)];
+      short effect=pat->data[curRow][4+(j<<1)];
+      short effectVal=pat->data[curRow][5+(j<<1)];
 
       if (effectVal==-1) effectVal=0;
 
@@ -147,7 +147,7 @@ void DivEngine::nextRow() {
             chan[i].portaNote=-1;
             chan[i].portaSpeed=-1;
           } else {
-            chan[i].portaNote=0x7f;
+            chan[i].portaNote=0x60;
             chan[i].portaSpeed=effectVal;
           }
           break;
@@ -167,11 +167,13 @@ void DivEngine::nextRow() {
           } else {
             chan[i].portaNote=chan[i].note;
             chan[i].portaSpeed=effectVal;
+            chan[i].doNote=false;
           }
           break;
         case 0x04: // vibrato
           chan[i].vibratoDepth=effectVal&15;
           chan[i].vibratoRate=effectVal>>4;
+          dispatch->dispatch(DivCommand(DIV_CMD_PITCH,i,(chan[i].vibratoDepth*vibTable[chan[i].vibratoPos])>>4));
           break;
         case 0x0a: // volume ramp
           if (effectVal!=0) {
@@ -187,17 +189,24 @@ void DivEngine::nextRow() {
         
         case 0xe1: // portamento up
           chan[i].portaNote=chan[i].note+(effectVal&15);
-          chan[i].portaSpeed=effectVal>>4;
+          chan[i].portaSpeed=(effectVal>>4)*3;
           break;
         case 0xe2: // portamento down
           chan[i].portaNote=chan[i].note-(effectVal&15);
-          chan[i].portaSpeed=effectVal>>4;
+          chan[i].portaSpeed=(effectVal>>4)*3;
           break;
         case 0xe5: // pitch
           chan[i].pitch=effectVal-0x80;
           break;
       }
     }
+
+    if (chan[i].doNote) {
+      chan[i].vibratoPos=0;
+      dispatch->dispatch(DivCommand(DIV_CMD_PITCH,i,(chan[i].vibratoDepth*vibTable[chan[i].vibratoPos])>>2));
+      dispatch->dispatch(DivCommand(DIV_CMD_NOTE_ON,i,chan[i].note));
+      chan[i].doNote=false;
+    }
   }
 }
 
@@ -228,6 +237,16 @@ void DivEngine::nextTick() {
       if (chan[i].volume<0) chan[i].volume=0;
       dispatch->dispatch(DivCommand(DIV_CMD_VOLUME,i,chan[i].volume>>8));
     }
+    if (chan[i].vibratoDepth>0) {
+      chan[i].vibratoPos+=chan[i].vibratoRate;
+      if (chan[i].vibratoPos>=60) chan[i].vibratoPos-=60;
+      dispatch->dispatch(DivCommand(DIV_CMD_PITCH,i,(chan[i].vibratoDepth*vibTable[chan[i].vibratoPos])>>4));
+    }
+    if (chan[i].portaSpeed>0) {
+      if (dispatch->dispatch(DivCommand(DIV_CMD_NOTE_PORTA,i,chan[i].portaSpeed,chan[i].portaNote))==2) {
+        chan[i].portaSpeed=0;
+      }
+    }
   }
 
   // system tick