diff --git a/index.html b/index.html
index 52be4dc6..cf234db9 100644
--- a/index.html
+++ b/index.html
@@ -278,6 +278,9 @@ if (window.location.host.endsWith('8bitworkshop.com')) {
     <div class="emucontrols-williams text-center small control-insns" style="display:none">
       <span class="control-def"><span class="control-key">A W S D</span> Move</span>
       <span class="control-def"><span class="control-key">&#x2190;&#x2191;&#x2193;&#x2192;</span> Fire</span>
+      <span class="control-def"><span class="control-key">\</span> Coin</span>
+      <span class="control-def"><span class="control-key small">Enter</span> Start</span>
+      <span class="control-def"><span class="control-key small">6 7 8 9</span> Extra</span>
     </div>
     <div class="emucontrols-astrocade text-center small control-insns" style="display:none">
       <span class="control-def"><span class="control-key">&#x2190;&#x2191;&#x2193;&#x2192;</span> Joystick</span>
diff --git a/presets/williams/test.xasm b/presets/williams/test.xasm
new file mode 100644
index 00000000..19db0727
--- /dev/null
+++ b/presets/williams/test.xasm
@@ -0,0 +1,28 @@
+
+palette	equ	$c000
+vidmem	equ	$0
+wdogx39	equ	$cbff
+
+Start:
+	ldx	#0
+Loop:
+        lda	>PALCONST,x
+        sta	palette,x
+        leax	1,x
+        cpx	#16
+        bne	Loop
+        
+	ldx	#0
+Loop2:
+        lda	#$39
+        sta	wdogx39
+        stx	,x
+        leax	1,x
+        cpx	#$9800
+        bne	Loop2
+        
+	jmp	Loop	; endless loop
+
+PALCONST:
+	fcb	$1,$2,$4,$8,$10,$20,$40,$80
+	fcb	$88,$c0,$e0,$f0,$f8,$fc,$fe,$ff
diff --git a/src/worker/workermain.ts b/src/worker/workermain.ts
index 7407615f..bfede6cf 100644
--- a/src/worker/workermain.ts
+++ b/src/worker/workermain.ts
@@ -104,6 +104,17 @@ var PLATFORM_PARAMS = {
       {name:'I/O Registers',start:0x6000,size:0x2000,type:'io'},
     ],
   },
+  'williams': {
+    code_start: 0x0,
+    rom_size: 0xc000,
+    data_start: 0x9800,
+    data_size: 0x2800,
+    stack_end: 0xc000,
+    extra_segments:[
+      {name:'Video RAM',start:0x0000,size:0xc000,type:'ram'},
+      {name:'I/O Registers',start:0xc000,size:0x1000,type:'io'},
+    ],
+  },
   'williams-z80': {
     code_start: 0x0,
     rom_size: 0x9800,
@@ -1908,10 +1919,9 @@ function translateShowdown(step:BuildStep) {
   };
 }
 
-// TODO
+// http://datapipe-blackbeltsystems.com/windows/flex/asm09.html
 function assembleXASM6809(step:BuildStep) {
   load("xasm6809");
-  var origin = 0; // TODO: configurable
   var alst = "";
   var lasterror = null;
   var errors = [];
@@ -1938,21 +1948,37 @@ function assembleXASM6809(step:BuildStep) {
   });
   var FS = Module['FS'];
   //setupFS(FS);
-  var code = getWorkFileAsString(step.path);
-  FS.writeFile("main.asm", code);
-  Module.callMain(["-c", "-l", "-s", "-y", "-o=main.bin", "main.asm"]);
+  populateFiles(step, FS, {
+    mainFilePath:'main.asm'
+  });
+  var binpath = step.prefix + '.bin';
+  var lstpath = step.prefix + '.lst'; // in stdout
+  Module.callMain(["-c", "-l", "-s", "-y", "-o="+binpath, step.path]);
   if (errors.length)
     return {errors:errors};
-  var aout = FS.readFile("main.bin", {encoding:'binary'});
-  putWorkFile('main.bin', aout);
-  // 00001    0000 [ 2] 1048                asld
-  var asmlines = parseListing(alst, /^\s*([0-9A-F]+)\s+([0-9A-F]+)\s+\[([0-9 ]+)\]\s+(\d+) (.*)/i, 1, 2, 4);
-  // TODO
+  var aout = FS.readFile(binpath, {encoding:'binary'});
+  if (aout.length == 0) {
+    console.log(alst);
+    errors.push({line:0, msg:"Empty output file"});
+    return {errors:errors};
+  }
+  putWorkFile(binpath, aout);
+  putWorkFile(lstpath, alst);
+  // TODO: symbol map
+  //mond09     0000     
+  var symbolmap = {};
+  //00005  W 0003 [ 8] A6890011            lda   >PALETTE,x
+  //00012    0011      0C0203              fcb   12,2,3
+  var asmlines = parseListing(alst, /^\s*([0-9]+) .+ ([0-9A-F]+)\s+\[([0-9 ]+)\]\s+([0-9A-F]+) (.*)/i, 1, 2, 4, 3);
+  var listings = {};
+  listings[step.prefix+'.lst'] = {lines:asmlines, text:alst};
+  var segments = step.params.extra_segments;
   return {
-      output:aout,
-      errors:errors,
-      lines:asmlines,
-      intermediate:{listing:alst},
+    output:aout,
+    listings:listings,
+    errors:errors,
+    symbolmap:symbolmap,
+    segments:segments
   };
 }
 
diff --git a/test/cli/testworker.js b/test/cli/testworker.js
index 5b1dfe90..6ef97a61 100644
--- a/test/cli/testworker.js
+++ b/test/cli/testworker.js
@@ -217,11 +217,9 @@ describe('Worker', function() {
   it('should NOT preprocess SDCC', function(done) {
     compile('sdcc', 'int x=0\n#bah\n', 'mw8080bw', done, 0, 0, 1);
   });
-  /*
   it('should compile XASM6809', function(done) {
     compile('xasm6809', '\tasld\n\tasld\n', 'williams', done, 4, 2, 0);
   });
-  */
   it('should link two files with SDCC', function(done) {
     var msgs = [
     {