Updated Closure Compiler to v20160911, so now we have a version that supports ECMAScript 6, but I'm not going to go bonkers on ES6 features just yet; the first feature I'm going to use is support for octal and binary constants (of the form 0onnnn and 0bnnnn)

modules/pdp11/lib/debugger.js

@@ -146,7 +146,7 @@ function DebuggerPDP11(parmsDbg)
         /*
          * Initialize DebuggerPDP11 message support
          */
-        this.afnDumpers = [];
+        this.afnDumpers = {};
         this.messageInit(parmsDbg['messages']);
 
         this.sInitCommands = parmsDbg['commands'];
@@ -3682,7 +3682,7 @@ if (DEBUGGER) {
     {
         var a = this.parseCommand(sCmds, fSave);
         for (var s in a) {
-            if (!this.doCommand(a[s])) return false;
+            if (!this.doCommand(a[+s])) return false;
         }
         return true;
     };

modules/pdp11/lib/defines.js

@@ -233,6 +233,12 @@ var PDP11 = {
         NORMAL:     0x0,        // write byte or word normally
         ZERO:       0x1,        // zero byte or word
         SIGNEXT:    0x2         // sign-extend a byte to a word
+    },
+    /*
+     * Assorted special (UNIBUS) addresses
+     */
+    UNIBUS: {
+        PSW:        0o177776
     }
 };