diff --git a/Makefile b/Makefile
index 2db18638..e37275c7 100644
--- a/Makefile
+++ b/Makefile
@@ -21,3 +21,7 @@ archive:
 	git archive --prefix 8bitworkshop- -o release/8bitworkshop-tools.zip HEAD tools
 
 
+web:
+	ifconfig | grep inet
+	python2 -m SimpleHTTPServer 2>> http.out
+
diff --git a/css/ui.css b/css/ui.css
index 0c38b524..8c49b3ee 100644
--- a/css/ui.css
+++ b/css/ui.css
@@ -98,6 +98,9 @@ div.mem_info {
   margin-left:8px;
   background-color: #666;
 }
+.btn_label {
+  color: #ccc;
+}
 .btn_group.debug_group {
 }
 .btn_group.view_group {
diff --git a/index.html b/index.html
index c0427c64..962393a4 100644
--- a/index.html
+++ b/index.html
@@ -39,10 +39,11 @@ ga('send', 'pageview');
         &#9776; <span class="caret"></span>
       </a>
       <ul class="dropdown-menu" aria-labelledby="dropdownMenuButton">
-        <li><a class="dropdown-item" href="#" id="item_new_file">New File...</a></li>
+      <li><a class="dropdown-item" href="#" id="item_new_file">New File...</a></li>
       <li><a class="dropdown-item" href="#" id="item_share_file">Share File as GitHub Gist...</a></li>
       <li><a class="dropdown-item" href="#" id="item_reset_file">Revert to Original...</a></li>
-      <li><a class="dropdown-item" href="#" id="item_download_rom">Download ROM Image...</a></li>
+      <li><a class="dropdown-item" href="#" id="item_download_file">Download File</a></li>
+      <li><a class="dropdown-item" href="#" id="item_download_rom">Download ROM Image</a></li>
       <li><a class="dropdown-item" href="#" id="item_record_video">Record Video...</a></li>
       <li class="dropdown dropdown-submenu">
         <a tabindex="-1" href="#">Debug</a>
@@ -50,6 +51,12 @@ ga('send', 'pageview');
           <li><a class="dropdown-item" href="#" id="item_debug_expr">Break Expression...</a></li>
         </ul>
       </li>
+      <li class="dropdown dropdown-submenu">
+        <a tabindex="-1" href="#">Options</a>
+        <ul class="dropdown-menu">
+          <li><i id="item_low_power_check" style="display:hidden" class="fa fa-check"></i><a class="dropdown-item" href="#" id="item_low_power">Low Power Mode</a></li>
+        </ul>
+      </li>
       <hr>
       <li class="dropdown dropdown-submenu">
          <a tabindex="-1" href="#">Platform</a>
@@ -82,7 +89,7 @@ ga('send', 'pageview');
   <span class="btn_group view_group" id="speed_bar" style="display:none">
     <button id="dbg_slowest" type="submit" title="Slowest"><span class="glyphicon glyphicon-fast-backward" aria-hidden="true"></span></button>
     <button id="dbg_slower" type="submit" title="Slower"><span class="glyphicon glyphicon-backward" aria-hidden="true"></span></button>
-    <span id="fps_label">60.00</span> fps
+    <span class="label"><span id="fps_label">60.00</span> fps</span>
     <button id="dbg_faster" type="submit" title="Faster"><span class="glyphicon glyphicon-forward" aria-hidden="true"></span></button>
     <button id="dbg_fastest" type="submit" title="Faster"><span class="glyphicon glyphicon-fast-forward" aria-hidden="true"></span></button>
   </span>
@@ -224,8 +231,10 @@ ga('send', 'pageview');
 </script>
 
 <script>
+/*
   var isFirefox = navigator.userAgent.toLowerCase().indexOf('firefox') > -1;
   if (!isFirefox && platform_id != 'vcs') { $("#best_in_firefox").show(); }
+*/
 </script>
 
 </body>
diff --git a/presets/verilog/femto16.json b/presets/verilog/femto16.json
index be99d5ca..e51094f8 100644
--- a/presets/verilog/femto16.json
+++ b/presets/verilog/femto16.json
@@ -25,6 +25,7 @@
     {"fmt":"pop ~reg",           "bits":["01001",0,"00001","110"]},
     {"fmt":"rts",                "bits":["01001","111","00001","110"]},
     {"fmt":"jsr ~reg",           "bits":["01110","111","00",0,"110"]},
+    {"fmt":"jsr ~imm16",         "bits":["0001110001011000",0,"0111011100100110"]},
 
     {"fmt":"bcc ~rel8",          "bits":["10000001",0]},
     {"fmt":"bcs ~rel8",          "bits":["10001001",0]},
diff --git a/presets/verilog/test.asm b/presets/verilog/test.asm
index 10a161be..503d460a 100644
--- a/presets/verilog/test.asm
+++ b/presets/verilog/test.asm
@@ -19,8 +19,8 @@
       mov       ax,@$4ffe
       mov       dx,@ClearTiles
       jsr       dx
-      mov       dx,@ClearSprites
-      jsr       dx
+      mov       ex,@ClearSprites
+      jsr       ex
       reset
 InitPageTable:
       mov       ax,@$6000       ; screen buffer
diff --git a/src/ui.js b/src/ui.js
index 78121e96..9d011301 100644
--- a/src/ui.js
+++ b/src/ui.js
@@ -372,6 +372,11 @@ function _downloadROMImage(e) {
   saveAs(blob, getCurrentFilename()+".rom");
 }
 
+function _downloadSourceFile(e) {
+  var blob = new Blob([editor.getValue()], {type: "text/plain;charset=utf-8"});
+  saveAs(blob, getCurrentFilename());
+}
+
 function populateExamples(sel) {
   sel.append($("<option />").text("--------- Examples ---------").attr('disabled',true));
   for (var i=0; i<PRESETS.length; i++) {
@@ -1312,6 +1317,7 @@ function setupDebugControls(){
   else
     $("#item_debug_expr").hide();
   $("#item_download_rom").click(_downloadROMImage);
+  $("#item_download_file").click(_downloadSourceFile);
   $("#item_record_video").click(_recordVideo);
   if (platform.setFrameRate && platform.getFrameRate) {
     $("#speed_bar").show();
diff --git a/src/worker/assembler.js b/src/worker/assembler.js
index 2ac8275b..6c308ba7 100644
--- a/src/worker/assembler.js
+++ b/src/worker/assembler.js
@@ -124,24 +124,30 @@ var Assembler = function(spec) {
   self.buildInstruction = function(rule, m) {
     var opcode = 0;
     var oplen = 0;
+    // iterate over each component of the rule output ("bits")
     for (var i=0; i<rule.bits.length; i++) {
       var b = rule.bits[i];
       var n,x;
+      // is a string? then it's a bit constant
+      // TODO
       if (b.length) {
         n = b.length;
         x = parseInt(b,2);
       } else {
+        // it's an indexed variable, look up its variable
         var id = m[b+1];
         var v = spec.vars[rule.varlist[b]];
         if (!v) {
           return {error:"Could not find matching identifier for '" + m[0] + "'"};
         }
         n = v.bits;
+        // is it an enumerated type? look up the index of its keyword
         if (v.toks) {
           x = v.toks.indexOf(id);
           if (x < 0)
             return null;
         } else {
+          // otherwise, parse it as a constant
           x = parseConst(id, n);
           // is it a label? add fixup
           if (isNaN(x)) {
@@ -158,14 +164,16 @@ var Assembler = function(spec) {
     }
     if (oplen == 0)
       warning("Opcode had zero length");
+    else if (oplen > 32)
+      warning("Opcodes > 32 bits not supported");
     else if ((oplen % width) != 0)
       warning("Opcode was not word-aligned (" + oplen + " bits)");
     return {opcode:opcode, nbits:oplen};
   }
 
   self.loadArch = function(arch) {
-    if (self.loadFile) {
-      var json = self.loadFile(arch + ".json");
+    if (self.loadJSON) {
+      var json = self.loadJSON(arch + ".json");
       if (json && json.vars && json.rules) {
         spec = json;
         preprocessRules();
@@ -292,13 +300,16 @@ if (typeof module !== 'undefined' && require.main === module) {
   var stdinBuffer = fs.readFileSync(0);
   var code = stdinBuffer.toString();
   var asm = new Assembler();
-  asm.loadFile = function(filename) {
-    return fs.readFileSync(filename, 'utf8');
+  asm.loadJSON = function(filename) {
+    return JSON.parse(fs.readFileSync(filename, 'utf8'));
+  };
+  asm.loadInclude = function(filename) {
+    filename = filename.substr(1, filename.length-2); // remove quotes
+    //return fs.readFileSync(filename, 'utf8');
+  };
+  asm.loadModule = function(top_module) {
+   //TODO
   };
   var out = asm.assembleFile(code);
-  if (out.errors) {
-    console.log(out.errors);
-  } else {
-    console.log(out.outwords);
-  }
+  console.log(out);
 }
diff --git a/src/worker/workermain.js b/src/worker/workermain.js
index 81dc8351..2179e864 100644
--- a/src/worker/workermain.js
+++ b/src/worker/workermain.js
@@ -1126,7 +1126,7 @@ function compileJSASM(asmcode, platform, options, is_inline) {
   load("assembler");
   var asm = new Assembler();
   var includes = [];
-  asm.loadFile = function(filename) {
+  asm.loadJSON = function(filename) {
     // TODO: what if it comes from dependencies?
     var path = '../../presets/' + platform + '/' + filename;
     var xhr = new XMLHttpRequest();