Debugger now stops on undefined opcodes, as well as on unknown I/O accesses

modules/pdp11/lib/bus.js

@@ -556,8 +556,7 @@ BusPDP11.prototype.unknownAccess = function(addr, data, fByte)
          * TODO: For 22-bit machines, let's display addr as a 3-byte value (for a total of 9 octal digits)
          */
         this.dbg.printMessage("warning: unknown I/O access (" + this.dbg.toStrBase(addr, 3) + "," + this.dbg.toStrBase(data) + "," + fByte + ")", true, true);
-        this.cpu.setPC(this.cpu.getLastPC());
-        this.cpu.stopCPU();
+        if (this.dbg.stopInstruction()) return 0;
     }
     if (!this.nDisableTraps) {
         this.cpu.trap(PDP11.TRAP.BUS_ERROR, addr);

modules/pdp11/lib/cpuops.js

@@ -1763,6 +1763,9 @@ PDP11.opXOR = function(opCode)
  */
 PDP11.opUndefined = function(opCode)
 {
+    if (DEBUGGER && this.dbg) {
+        this.dbg.undefinedInstruction(opCode);
+    }
     this.trap(PDP11.TRAP.RESERVED, PDP11.REASON.RESERVED);
 };
 

modules/pdp11/lib/debugger.js

@@ -1607,6 +1607,37 @@ if (DEBUGGER) {
         return false;
     };
 
+    /**
+     * stopInstruction()
+     *
+     * TODO: Currently, the only way to prevent this call from stopping the CPU is when you're single-stepping.
+     *
+     * @this {DebuggerPDP11}
+     * @return {boolean} true if stopping is enabled, false if not
+     */
+    DebuggerPDP11.prototype.stopInstruction = function()
+    {
+        var cpu = this.cpu;
+        if (cpu.isRunning()) {
+            cpu.setPC(this.cpu.getLastPC());
+            this.stopCPU();
+            return true;
+        }
+        return false;
+    };
+
+    /**
+     * undefinedInstruction(opCode)
+     *
+     * @this {DebuggerPDP11}
+     * @param {number} opCode
+     */
+    DebuggerPDP11.prototype.undefinedInstruction = function(opCode)
+    {
+        this.printMessage("undefined opcode " + this.toStrBase(opCode), true, true);
+        this.stopInstruction();         // allow the caller to step over it if they really want a trap generated
+    };
+
     /**
      * checkMemoryRead(addr, nb)
      *