diff --git a/src/devices.ts b/src/devices.ts
index 825834a2..83d017ae 100644
--- a/src/devices.ts
+++ b/src/devices.ts
@@ -113,68 +113,6 @@ export function xorshift32(x : number) : number {
   return x;
 }
 
-/// HOOKS
-
-export interface Hook<T> {
-  //target : T;
-  unhook();
-}
-
-export class BusHook implements Hook<Bus> {
-  //target : Bus;
-  constructor(bus : Bus, profiler : ProbeBus) {
-    //this.target = bus;
-    var oldread = bus.read.bind(bus);
-    var oldwrite = bus.write.bind(bus);
-    bus.read = (a:number):number => {
-      var val = oldread(a);
-      profiler.logRead(a,val);
-      return val;
-    }
-    bus.write = (a:number,v:number) => {
-      profiler.logWrite(a,v);
-      oldwrite(a,v);
-    }
-    this.unhook = () => {
-      bus.read = oldread;
-      bus.write = oldwrite;
-    }
-  }
-  unhook : () => void;
-}
-
-export class CPUClockHook implements Hook<CPU&ClockBased> {
-  //target : CPU&ClockBased;
-  constructor(cpu : CPU&ClockBased, profiler : ProbeCPU) {
-    //this.target = cpu;
-    var oldclock = cpu.advanceClock.bind(cpu);
-    cpu.advanceClock = () => {
-      profiler.logExecute(cpu.getPC());
-      return oldclock();
-    }
-    this.unhook = () => {
-      cpu.advanceClock = oldclock;
-    }
-  }
-  unhook : () => void;
-}
-
-export class CPUInsnHook implements Hook<CPU&InstructionBased> {
-  //target : CPU&InstructionBased;
-  constructor(cpu : CPU&InstructionBased, profiler : ProbeCPU) {
-    //this.target = cpu;
-    var oldinsn = cpu.advanceInsn.bind(cpu);
-    cpu.advanceInsn = () => {
-      profiler.logExecute(cpu.getPC());
-      return oldinsn();
-    }
-    this.unhook = () => {
-      cpu.advanceInsn = oldinsn;
-    }
-  }
-  unhook : () => void;
-}
-
 /// PROFILER
 
 export interface ProbeTime {
@@ -184,7 +122,7 @@ export interface ProbeTime {
 }
 
 export interface ProbeCPU {
-  logExecute(address:number);
+  logExecute(address:number, SP:number);
   logInterrupt(type:number);
   logIllegal(address:number);
 }
@@ -288,7 +226,7 @@ export abstract class BasicHeadlessMachine implements HasCPU, Bus, AcceptsROM, P
   advanceCPU() {
     var c = this.cpu as any;
     var n = 1;
-    if (this.cpu.isStable()) { this.probe.logExecute(this.cpu.getPC()); }
+    if (this.cpu.isStable()) { this.probe.logExecute(this.cpu.getPC(), this.cpu.getSP()); }
     if (c.advanceClock) { c.advanceClock(); }
     else if (c.advanceInsn) { n = c.advanceInsn(1); }
     this.probe.logClocks(n);
diff --git a/src/platform/nes.ts b/src/platform/nes.ts
index a2cb3690..917814d5 100644
--- a/src/platform/nes.ts
+++ b/src/platform/nes.ts
@@ -138,7 +138,7 @@ class JSNESPlatform extends Base6502Platform implements Platform, Probeable {
     // insert debug hook
     this.nes.cpu._emulate = this.nes.cpu.emulate;
     this.nes.cpu.emulate = () => {
-      this.probe.logExecute(this.nes.cpu.REG_PC-1);
+      this.probe.logExecute(this.nes.cpu.REG_PC-1, this.nes.cpu.REG_SP);
       var cycles = this.nes.cpu._emulate();
       this.evalDebugCondition();
       this.probe.logClocks(cycles);
diff --git a/src/recorder.ts b/src/recorder.ts
index 2f333cf9..9b04dcff 100644
--- a/src/recorder.ts
+++ b/src/recorder.ts
@@ -130,6 +130,8 @@ export enum ProbeFlags {
   VRAM_WRITE	= 0x07000000,
   INTERRUPT	= 0x08000000,
   ILLEGAL	= 0x09000000,
+  SP_PUSH	= 0x0a000000,
+  SP_POP	= 0x0b000000,
   SCANLINE	= 0x7e000000,
   FRAME		= 0x7f000000,
 }
@@ -145,6 +147,7 @@ export class ProbeRecorder implements ProbeAll {
   idx = 0;
   fclk = 0;
   sl = 0;
+  cur_sp = -1;
   m : Probeable;
   singleFrame : boolean = true;
 
@@ -161,7 +164,7 @@ export class ProbeRecorder implements ProbeAll {
     this.idx = 0;
   }
   log(a:number) {
-    // TODO: coalesce READ and EXECUTE
+    // TODO: coalesce READ and EXECUTE and PUSH/POP
     if (this.idx >= this.buf.length) return;
     this.buf[this.idx++] = a;
   }
@@ -198,7 +201,16 @@ export class ProbeRecorder implements ProbeAll {
     this.sl = 0;
     if (this.singleFrame) this.reset();
   }
-  logExecute(address:number) {
+  logExecute(address:number, SP:number) {
+    if (this.cur_sp !== SP) {
+      if (SP < this.cur_sp) {
+        this.log(ProbeFlags.SP_PUSH | (this.cur_sp - SP));
+      }
+      if (SP > this.cur_sp) {
+        this.log(ProbeFlags.SP_POP | (SP - this.cur_sp));
+      }
+      this.cur_sp = SP;
+    }
     this.log(address | ProbeFlags.EXECUTE);
   }
   logInterrupt(type:number) {
diff --git a/src/ui.ts b/src/ui.ts
index 121e0d16..4d910494 100644
--- a/src/ui.ts
+++ b/src/ui.ts
@@ -276,6 +276,9 @@ function refreshWindowList() {
     addWindowItem("#crtheatmap", "CRT Probe", () => {
       return new Views.RasterPCHeatMapView();
     });
+    addWindowItem("#spheatmap", "Stack Probe", () => {
+      return new Views.RasterStackMapView();
+    });
   }
   addWindowItem('#asseteditor', 'Asset Editor', () => {
     return new Views.AssetEditorView();
diff --git a/src/views.ts b/src/views.ts
index eea15802..55d9e941 100644
--- a/src/views.ts
+++ b/src/views.ts
@@ -1055,7 +1055,6 @@ export class RasterHeatMapView extends ProbeBitmapViewBase implements ProjectVie
     data = data | rgb | 0xff000000;
     this.datau32[iofs] = data;
   }
-  
 }
 */
 
@@ -1069,7 +1068,43 @@ export class RasterPCHeatMapView extends ProbeBitmapViewBase implements ProjectV
     data = data | rgb | 0xff000000;
     this.datau32[iofs] = data;
   }
-  
+}
+
+export class RasterStackMapView extends ProbeBitmapViewBase implements ProjectView {
+  pcstack = [];
+  pushed = false;
+  color = 0;
+  root = {};
+
+  drawEvent(op, addr, col, row) {
+    var iofs = col + row * this.canvas.width;
+    if (op == ProbeFlags.SP_PUSH) {
+      this.pcstack.push({});
+      this.pushed = true;
+    } else if (op == ProbeFlags.SP_POP) {
+      var entry = this.pcstack.pop();
+      if (entry && entry.addr !== undefined) {
+        var node = this.root;
+        for (var e of this.pcstack) {
+          if (node[e.addr]) {
+            node = node[e.addr];
+          } else {
+            node = node[e.addr] = {};
+          }
+        }
+      }
+      //if (this.pcstack.length == 1) console.log(this.root);
+      this.pushed = false;
+    } else if (op == ProbeFlags.EXECUTE) {
+      if (this.pushed) {
+        this.pcstack.pop();
+        this.pcstack.push({addr:addr, scol:col, srow:row});
+        this.pushed = false;
+      }
+    }
+    var data = 0xff224488 << this.pcstack.length;
+    this.datau32[iofs] = data;
+  }
 }
 
 ///