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authorKartik Agaram <vc@akkartik.com>2020-09-07 16:38:14 -0700
committerKartik Agaram <vc@akkartik.com>2020-09-07 16:39:44 -0700
commit68df24fa778f7f5a2651a4623681f38dc920c490 (patch)
tree99d95cf1812e90ad6bfd4f7292ee42b6a5e7c935 /html/403unicode.mu.html
parenta0430d580719fc0fbe1fe0c92de2ec412245762c (diff)
downloadmu-68df24fa778f7f5a2651a4623681f38dc920c490.tar.gz
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
+<html>
+<head>
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+<title>Mu - 403unicode.mu</title>
+<meta name="Generator" content="Vim/8.1">
+<meta name="plugin-version" content="vim8.1_v1">
+<meta name="syntax" content="none">
+<meta name="settings" content="number_lines,use_css,pre_wrap,no_foldcolumn,expand_tabs,line_ids,prevent_copy=">
+<meta name="colorscheme" content="minimal-light">
+<style type="text/css">
+<!--
+pre { white-space: pre-wrap; font-family: monospace; color: #000000; background-color: #c6c6c6; }
+body { font-size:12pt; font-family: monospace; color: #000000; background-color: #c6c6c6; }
+a { color:inherit; }
+* { font-size:12pt; font-size: 1em; }
+.muTest { color: #5f8700; }
+.LineNr { }
+.muFunction { color: #af5f00; text-decoration: underline; }
+.SpecialChar { color: #d70000; }
+.CommentedCode { color: #8a8a8a; }
+.Comment { color: #005faf; }
+.Constant { color: #008787; }
+.Delimiter { color: #c000c0; }
+.PreProc { color: #c000c0; }
+-->
+</style>
+
+<script type='text/javascript'>
+<!--
+
+/* function to open any folds containing a jumped-to line before jumping to it */
+function JumpToLine()
+{
+  var lineNum;
+  lineNum = window.location.hash;
+  lineNum = lineNum.substr(1); /* strip off '#' */
+
+  if (lineNum.indexOf('L') == -1) {
+    lineNum = 'L'+lineNum;
+  }
+  var lineElem = document.getElementById(lineNum);
+  /* Always jump to new location even if the line was hidden inside a fold, or
+   * we corrected the raw number to a line ID.
+   */
+  if (lineElem) {
+    lineElem.scrollIntoView(true);
+  }
+  return true;
+}
+if ('onhashchange' in window) {
+  window.onhashchange = JumpToLine;
+}
+
+-->
+</script>
+</head>
+<body onload='JumpToLine();'>
+<a href='https://github.com/akkartik/mu/blob/master/403unicode.mu'>https://github.com/akkartik/mu/blob/master/403unicode.mu</a>
+<pre id='vimCodeElement'>
+<span id="L1" class="LineNr">  1 </span><span class="Comment"># Helpers for Unicode.</span>
+<span id="L2" class="LineNr">  2 </span><span class="Comment">#</span>
+<span id="L3" class="LineNr">  3 </span><span class="Comment"># Mu has no characters, only code points and graphemes.</span>
+<span id="L4" class="LineNr">  4 </span><span class="Comment"># Code points are the indivisible atoms of text streams.</span>
+<span id="L5" class="LineNr">  5 </span><span class="Comment">#   <a href="https://en.wikipedia.org/wiki/Code_point">https://en.wikipedia.org/wiki/Code_point</a></span>
+<span id="L6" class="LineNr">  6 </span><span class="Comment"># Graphemes are the smallest self-contained unit of text.</span>
+<span id="L7" class="LineNr">  7 </span><span class="Comment"># Graphemes may consist of multiple code points.</span>
+<span id="L8" class="LineNr">  8 </span><span class="Comment">#</span>
+<span id="L9" class="LineNr">  9 </span><span class="Comment"># Mu graphemes are always represented in utf-8, and they are required to fit</span>
+<span id="L10" class="LineNr"> 10 </span><span class="Comment"># in 4 bytes.</span>
+<span id="L11" class="LineNr"> 11 </span><span class="Comment">#</span>
+<span id="L12" class="LineNr"> 12 </span><span class="Comment"># Mu doesn't currently support combining code points, or graphemes made of</span>
+<span id="L13" class="LineNr"> 13 </span><span class="Comment"># multiple code points. One day we will.</span>
+<span id="L14" class="LineNr"> 14 </span><span class="Comment"># We also don't currently support code points that translate into multiple</span>
+<span id="L15" class="LineNr"> 15 </span><span class="Comment"># or wide graphemes. (In particular, Tab will never be supported.)</span>
+<span id="L16" class="LineNr"> 16 </span>
+<span id="L17" class="LineNr"> 17 </span><span class="Comment"># transliterated from tb_utf8_unicode_to_char in <a href="https://github.com/nsf/termbox">https://github.com/nsf/termbox</a></span>
+<span id="L18" class="LineNr"> 18 </span><span class="Comment"># <a href="https://wiki.tcl-lang.org/page/UTF%2D8+bit+by+bit">https://wiki.tcl-lang.org/page/UTF%2D8+bit+by+bit</a> explains the algorithm</span>
+<span id="L19" class="LineNr"> 19 </span><span class="Comment">#</span>
+<span id="L20" class="LineNr"> 20 </span><span class="Comment"># The day we want to support combining characters, this function will need to</span>
+<span id="L21" class="LineNr"> 21 </span><span class="Comment"># take multiple code points. Or something.</span>
+<span id="L22" class="LineNr"> 22 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='403unicode.mu.html#L22'>to-grapheme</a></span> in: code-point<span class="PreProc"> -&gt; </span>out/<span class="Constant">eax</span>: grapheme <span class="Delimiter">{</span>
+<span id="L23" class="LineNr"> 23 </span>$to-grapheme:body: <span class="Delimiter">{</span>
+<span id="L24" class="LineNr"> 24 </span>  <span class="PreProc">var</span> c/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy in
+<span id="L25" class="LineNr"> 25 </span>  <span class="PreProc">var</span> num-trailers/<span class="Constant">ecx</span>: int <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0</span>
+<span id="L26" class="LineNr"> 26 </span>  <span class="PreProc">var</span> first/<span class="Constant">edx</span>: int <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0</span>
+<span id="L27" class="LineNr"> 27 </span>  $to-grapheme:compute-length: <span class="Delimiter">{</span>
+<span id="L28" class="LineNr"> 28 </span>    <span class="Comment"># single byte: just return it</span>
+<span id="L29" class="LineNr"> 29 </span>    compare c, <span class="Constant">0x7f</span>
+<span id="L30" class="LineNr"> 30 </span>    <span class="Delimiter">{</span>
+<span id="L31" class="LineNr"> 31 </span>      <span class="PreProc">break-if-&gt;</span>
+<span id="L32" class="LineNr"> 32 </span>      out <span class="SpecialChar">&lt;-</span> copy c
+<span id="L33" class="LineNr"> 33 </span>      <span class="PreProc">break</span> $to-grapheme:body
+<span id="L34" class="LineNr"> 34 </span>    <span class="Delimiter">}</span>
+<span id="L35" class="LineNr"> 35 </span>    <span class="Comment"># 2 bytes</span>
+<span id="L36" class="LineNr"> 36 </span>    compare c, <span class="Constant">0x7ff</span>
+<span id="L37" class="LineNr"> 37 </span>    <span class="Delimiter">{</span>
+<span id="L38" class="LineNr"> 38 </span>      <span class="PreProc">break-if-&gt;</span>
+<span id="L39" class="LineNr"> 39 </span>      num-trailers <span class="SpecialChar">&lt;-</span> copy <span class="Constant">1</span>
+<span id="L40" class="LineNr"> 40 </span>      first <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0xc0</span>
+<span id="L41" class="LineNr"> 41 </span>      <span class="PreProc">break</span> $to-grapheme:compute-length
+<span id="L42" class="LineNr"> 42 </span>    <span class="Delimiter">}</span>
+<span id="L43" class="LineNr"> 43 </span>    <span class="Comment"># 3 bytes</span>
+<span id="L44" class="LineNr"> 44 </span>    compare c, <span class="Constant">0xffff</span>
+<span id="L45" class="LineNr"> 45 </span>    <span class="Delimiter">{</span>
+<span id="L46" class="LineNr"> 46 </span>      <span class="PreProc">break-if-&gt;</span>
+<span id="L47" class="LineNr"> 47 </span>      num-trailers <span class="SpecialChar">&lt;-</span> copy <span class="Constant">2</span>
+<span id="L48" class="LineNr"> 48 </span>      first <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0xe0</span>
+<span id="L49" class="LineNr"> 49 </span>      <span class="PreProc">break</span> $to-grapheme:compute-length
+<span id="L50" class="LineNr"> 50 </span>    <span class="Delimiter">}</span>
+<span id="L51" class="LineNr"> 51 </span>    <span class="Comment"># 4 bytes</span>
+<span id="L52" class="LineNr"> 52 </span>    compare c, <span class="Constant">0x1fffff</span>
+<span id="L53" class="LineNr"> 53 </span>    <span class="Delimiter">{</span>
+<span id="L54" class="LineNr"> 54 </span>      <span class="PreProc">break-if-&gt;</span>
+<span id="L55" class="LineNr"> 55 </span>      num-trailers <span class="SpecialChar">&lt;-</span> copy <span class="Constant">3</span>
+<span id="L56" class="LineNr"> 56 </span>      first <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0xf0</span>
+<span id="L57" class="LineNr"> 57 </span>      <span class="PreProc">break</span> $to-grapheme:compute-length
+<span id="L58" class="LineNr"> 58 </span>    <span class="Delimiter">}</span>
+<span id="L59" class="LineNr"> 59 </span>    <span class="Comment"># more than 4 bytes: unsupported</span>
+<span id="L60" class="LineNr"> 60 </span>    <span class="Comment"># TODO: print to stderr</span>
+<span id="L61" class="LineNr"> 61 </span>    compare c, <span class="Constant">0x1fffff</span>
+<span id="L62" class="LineNr"> 62 </span>    <span class="Delimiter">{</span>
+<span id="L63" class="LineNr"> 63 </span>      <span class="PreProc">break-if-&gt;</span>
+<span id="L64" class="LineNr"> 64 </span>      <a href='304screen.subx.html#L122'>print-string-to-real-screen</a> <span class="Constant">&quot;unsupported code point &quot;</span>
+<span id="L65" class="LineNr"> 65 </span>      <a href='304screen.subx.html#L213'>print-int32-hex-to-real-screen</a> c
+<span id="L66" class="LineNr"> 66 </span>      <a href='304screen.subx.html#L122'>print-string-to-real-screen</a> <span class="Constant">&quot;\n&quot;</span>
+<span id="L67" class="LineNr"> 67 </span>      <span class="PreProc">var</span> exit-status/<span class="Constant">ebx</span>: int <span class="SpecialChar">&lt;-</span> copy <span class="Constant">1</span>
+<span id="L68" class="LineNr"> 68 </span>      syscall_exit
+<span id="L69" class="LineNr"> 69 </span>    <span class="Delimiter">}</span>
+<span id="L70" class="LineNr"> 70 </span>  <span class="Delimiter">}</span>
+<span id="L71" class="LineNr"> 71 </span>  <span class="Comment"># emit trailer bytes, 6 bits from 'in', first two bits '10'</span>
+<span id="L72" class="LineNr"> 72 </span>  <span class="PreProc">var</span> result/<span class="Constant">edi</span>: int <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0</span>
+<span id="L73" class="LineNr"> 73 </span>  <span class="Delimiter">{</span>
+<span id="L74" class="LineNr"> 74 </span>    compare num-trailers, <span class="Constant">0</span>
+<span id="L75" class="LineNr"> 75 </span>    <span class="PreProc">break-if-&lt;=</span>
+<span id="L76" class="LineNr"> 76 </span>    <span class="PreProc">var</span> tmp/<span class="Constant">esi</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L77" class="LineNr"> 77 </span>    tmp <span class="SpecialChar">&lt;-</span> and <span class="Constant">0x3f</span>
+<span id="L78" class="LineNr"> 78 </span>    tmp <span class="SpecialChar">&lt;-</span> or <span class="Constant">0x80</span>
+<span id="L79" class="LineNr"> 79 </span>    result <span class="SpecialChar">&lt;-</span> shift-left <span class="Constant">8</span>
+<span id="L80" class="LineNr"> 80 </span>    result <span class="SpecialChar">&lt;-</span> or tmp
+<span id="L81" class="LineNr"> 81 </span>    <span class="Comment"># update loop state</span>
+<span id="L82" class="LineNr"> 82 </span>    c <span class="SpecialChar">&lt;-</span> shift-right <span class="Constant">6</span>
+<span id="L83" class="LineNr"> 83 </span>    num-trailers <span class="SpecialChar">&lt;-</span> decrement
+<span id="L84" class="LineNr"> 84 </span>    <span class="PreProc">loop</span>
+<span id="L85" class="LineNr"> 85 </span>  <span class="Delimiter">}</span>
+<span id="L86" class="LineNr"> 86 </span>  <span class="Comment"># emit engine</span>
+<span id="L87" class="LineNr"> 87 </span>  result <span class="SpecialChar">&lt;-</span> shift-left <span class="Constant">8</span>
+<span id="L88" class="LineNr"> 88 </span>  result <span class="SpecialChar">&lt;-</span> or c
+<span id="L89" class="LineNr"> 89 </span>  result <span class="SpecialChar">&lt;-</span> or first
+<span id="L90" class="LineNr"> 90 </span>  <span class="Comment">#</span>
+<span id="L91" class="LineNr"> 91 </span>  out <span class="SpecialChar">&lt;-</span> copy result
+<span id="L92" class="LineNr"> 92 </span><span class="Delimiter">}</span>
+<span id="L93" class="LineNr"> 93 </span><span class="Delimiter">}</span>
+<span id="L94" class="LineNr"> 94 </span>
+<span id="L95" class="LineNr"> 95 </span><span class="Comment"># single-byte code point have identical graphemes</span>
+<span id="L96" class="LineNr"> 96 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L96'>test-to-grapheme-single-byte</a></span> <span class="Delimiter">{</span>
+<span id="L97" class="LineNr"> 97 </span>  <span class="PreProc">var</span> in-int/<span class="Constant">ecx</span>: int <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0</span>
+<span id="L98" class="LineNr"> 98 </span>  <span class="Delimiter">{</span>
+<span id="L99" class="LineNr"> 99 </span>    compare in-int, <span class="Constant">0x7f</span>
+<span id="L100" class="LineNr">100 </span>    <span class="PreProc">break-if-&gt;</span>
+<span id="L101" class="LineNr">101 </span>    <span class="PreProc">var</span> in/<span class="Constant">eax</span>: code-point <span class="SpecialChar">&lt;-</span> copy in-int
+<span id="L102" class="LineNr">102 </span>    <span class="PreProc">var</span> out/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L22'>to-grapheme</a> in
+<span id="L103" class="LineNr">103 </span>    <span class="PreProc">var</span> out-int/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy out
+<span id="L104" class="LineNr">104 </span>    <a href='102test.subx.html#L23'>check-ints-equal</a> out-int, in-int, <span class="Constant">&quot;F - test-to-grapheme-single-byte&quot;</span>
+<span id="L105" class="LineNr">105 </span>    in-int <span class="SpecialChar">&lt;-</span> increment
+<span id="L106" class="LineNr">106 </span>    <span class="PreProc">loop</span>
+<span id="L107" class="LineNr">107 </span>  <span class="Delimiter">}</span>
+<span id="L108" class="LineNr">108 </span><span class="Delimiter">}</span>
+<span id="L109" class="LineNr">109 </span>
+<span id="L110" class="LineNr">110 </span>                                                              <span class="Comment"># byte       | byte      | byte      | byte</span>
+<span id="L111" class="LineNr">111 </span><span class="Comment"># smallest 2-byte utf-8</span>
+<span id="L112" class="LineNr">112 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L112'>test-to-grapheme-two-bytes-min</a></span> <span class="Delimiter">{</span>
+<span id="L113" class="LineNr">113 </span>  <span class="PreProc">var</span> in/<span class="Constant">eax</span>: code-point <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0x80</span>                         <span class="Comment">#                                 10     00-0000</span>
+<span id="L114" class="LineNr">114 </span>  <span class="PreProc">var</span> out/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L22'>to-grapheme</a> in
+<span id="L115" class="LineNr">115 </span>  <span class="PreProc">var</span> out-int/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy out
+<span id="L116" class="LineNr">116 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> out-int, <span class="Constant">0x80c2</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L22'>to-grapheme</a>/2a&quot;</span>      <span class="Comment">#                         110 0-0010  10 00-0000</span>
+<span id="L117" class="LineNr">117 </span><span class="Delimiter">}</span>
+<span id="L118" class="LineNr">118 </span>
+<span id="L119" class="LineNr">119 </span><span class="Comment"># largest 2-byte utf-8</span>
+<span id="L120" class="LineNr">120 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L120'>test-to-grapheme-two-bytes-max</a></span> <span class="Delimiter">{</span>
+<span id="L121" class="LineNr">121 </span>  <span class="PreProc">var</span> in/<span class="Constant">eax</span>: code-point <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0x7ff</span>                        <span class="Comment">#                             1-1111     11-1111</span>
+<span id="L122" class="LineNr">122 </span>  <span class="PreProc">var</span> out/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L22'>to-grapheme</a> in
+<span id="L123" class="LineNr">123 </span>  <span class="PreProc">var</span> out-int/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy out
+<span id="L124" class="LineNr">124 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> out-int, <span class="Constant">0xbfdf</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L22'>to-grapheme</a>/2b&quot;</span>      <span class="Comment">#                         110 1-1111  10 11-1111</span>
+<span id="L125" class="LineNr">125 </span><span class="Delimiter">}</span>
+<span id="L126" class="LineNr">126 </span>
+<span id="L127" class="LineNr">127 </span><span class="Comment"># smallest 3-byte utf-8</span>
+<span id="L128" class="LineNr">128 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L128'>test-to-grapheme-three-bytes-min</a></span> <span class="Delimiter">{</span>
+<span id="L129" class="LineNr">129 </span>  <span class="PreProc">var</span> in/<span class="Constant">eax</span>: code-point <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0x800</span>                        <span class="Comment">#                            10-0000     00-0000</span>
+<span id="L130" class="LineNr">130 </span>  <span class="PreProc">var</span> out/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L22'>to-grapheme</a> in
+<span id="L131" class="LineNr">131 </span>  <span class="PreProc">var</span> out-int/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy out
+<span id="L132" class="LineNr">132 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> out-int, <span class="Constant">0x80a0e0</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L22'>to-grapheme</a>/3a&quot;</span>    <span class="Comment">#              1110 0000  10 10-0000  10 00-0000</span>
+<span id="L133" class="LineNr">133 </span><span class="Delimiter">}</span>
+<span id="L134" class="LineNr">134 </span>
+<span id="L135" class="LineNr">135 </span><span class="Comment"># largest 3-byte utf-8</span>
+<span id="L136" class="LineNr">136 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L136'>test-to-grapheme-three-bytes-max</a></span> <span class="Delimiter">{</span>
+<span id="L137" class="LineNr">137 </span>  <span class="PreProc">var</span> in/<span class="Constant">eax</span>: code-point <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0xffff</span>                       <span class="Comment">#                   1111     11-1111     11-1111</span>
+<span id="L138" class="LineNr">138 </span>  <span class="PreProc">var</span> out/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L22'>to-grapheme</a> in
+<span id="L139" class="LineNr">139 </span>  <span class="PreProc">var</span> out-int/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy out
+<span id="L140" class="LineNr">140 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> out-int, <span class="Constant">0xbfbfef</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L22'>to-grapheme</a>/3b&quot;</span>    <span class="Comment">#              1110 1111  10 11-1111  10 11-1111</span>
+<span id="L141" class="LineNr">141 </span><span class="Delimiter">}</span>
+<span id="L142" class="LineNr">142 </span>
+<span id="L143" class="LineNr">143 </span><span class="Comment"># smallest 4-byte utf-8</span>
+<span id="L144" class="LineNr">144 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L144'>test-to-grapheme-four-bytes-min</a></span> <span class="Delimiter">{</span>
+<span id="L145" class="LineNr">145 </span>  <span class="PreProc">var</span> in/<span class="Constant">eax</span>: code-point <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0x10000</span>                      <span class="Comment">#                 1-0000     00-0000     00-0000</span>
+<span id="L146" class="LineNr">146 </span>  <span class="PreProc">var</span> out/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L22'>to-grapheme</a> in
+<span id="L147" class="LineNr">147 </span>  <span class="PreProc">var</span> out-int/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy out
+<span id="L148" class="LineNr">148 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> out-int, <span class="Constant">0x808090f0</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L22'>to-grapheme</a>/4a&quot;</span>  <span class="Comment"># 1111-0 000  10 01-0000  10 00-0000  10 00-0000</span>
+<span id="L149" class="LineNr">149 </span><span class="Delimiter">}</span>
+<span id="L150" class="LineNr">150 </span>
+<span id="L151" class="LineNr">151 </span><span class="Comment"># largest 4-byte utf-8</span>
+<span id="L152" class="LineNr">152 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L152'>test-to-grapheme-four-bytes-max</a></span> <span class="Delimiter">{</span>
+<span id="L153" class="LineNr">153 </span>  <span class="PreProc">var</span> in/<span class="Constant">eax</span>: code-point <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0x1fffff</span>                     <span class="Comment">#        111     11-1111     11-1111     11-1111</span>
+<span id="L154" class="LineNr">154 </span>  <span class="PreProc">var</span> out/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L22'>to-grapheme</a> in
+<span id="L155" class="LineNr">155 </span>  <span class="PreProc">var</span> out-int/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy out
+<span id="L156" class="LineNr">156 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> out-int, <span class="Constant">0xbfbfbff7</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L22'>to-grapheme</a>/4b&quot;</span>  <span class="Comment"># 1111-0 111  10 11-1111  10 11-1111  10 11-1111</span>
+<span id="L157" class="LineNr">157 </span><span class="Delimiter">}</span>
+<span id="L158" class="LineNr">158 </span>
+<span id="L159" class="LineNr">159 </span><span class="Comment"># read the next grapheme from a stream of bytes</span>
+<span id="L160" class="LineNr">160 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='403unicode.mu.html#L160'>read-grapheme</a></span> in: (addr stream byte)<span class="PreProc"> -&gt; </span>out/<span class="Constant">eax</span>: grapheme <span class="Delimiter">{</span>
+<span id="L161" class="LineNr">161 </span>$read-grapheme:body: <span class="Delimiter">{</span>
+<span id="L162" class="LineNr">162 </span>  <span class="PreProc">var</span> c/<span class="Constant">eax</span>: byte <span class="SpecialChar">&lt;-</span> <a href='112read-byte.subx.html#L273'>read-byte</a> in
+<span id="L163" class="LineNr">163 </span>  <span class="PreProc">var</span> num-trailers/<span class="Constant">ecx</span>: int <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0</span>
+<span id="L164" class="LineNr">164 </span>  $read-grapheme:compute-length: <span class="Delimiter">{</span>
+<span id="L165" class="LineNr">165 </span>    <span class="Comment"># single byte: just return it</span>
+<span id="L166" class="LineNr">166 </span>    compare c, <span class="Constant">0xc0</span>
+<span id="L167" class="LineNr">167 </span>    <span class="Delimiter">{</span>
+<span id="L168" class="LineNr">168 </span>      <span class="PreProc">break-if-&gt;=</span>
+<span id="L169" class="LineNr">169 </span>      out <span class="SpecialChar">&lt;-</span> copy c
+<span id="L170" class="LineNr">170 </span>      num-trailers <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0</span>
+<span id="L171" class="LineNr">171 </span>      <span class="PreProc">break</span> $read-grapheme:body
+<span id="L172" class="LineNr">172 </span>    <span class="Delimiter">}</span>
+<span id="L173" class="LineNr">173 </span>    compare c, <span class="Constant">0xfe</span>
+<span id="L174" class="LineNr">174 </span>    <span class="Delimiter">{</span>
+<span id="L175" class="LineNr">175 </span>      <span class="PreProc">break-if-&lt;</span>
+<span id="L176" class="LineNr">176 </span>      out <span class="SpecialChar">&lt;-</span> copy c
+<span id="L177" class="LineNr">177 </span>      <span class="PreProc">break</span> $read-grapheme:body
+<span id="L178" class="LineNr">178 </span>    <span class="Delimiter">}</span>
+<span id="L179" class="LineNr">179 </span>    <span class="Comment"># 2 bytes</span>
+<span id="L180" class="LineNr">180 </span>    compare c, <span class="Constant">0xe0</span>
+<span id="L181" class="LineNr">181 </span>    <span class="Delimiter">{</span>
+<span id="L182" class="LineNr">182 </span>      <span class="PreProc">break-if-&gt;=</span>
+<span id="L183" class="LineNr">183 </span>      num-trailers <span class="SpecialChar">&lt;-</span> copy <span class="Constant">1</span>
+<span id="L184" class="LineNr">184 </span>      <span class="PreProc">break</span> $read-grapheme:compute-length
+<span id="L185" class="LineNr">185 </span>    <span class="Delimiter">}</span>
+<span id="L186" class="LineNr">186 </span>    <span class="Comment"># 3 bytes</span>
+<span id="L187" class="LineNr">187 </span>    compare c, <span class="Constant">0xf0</span>
+<span id="L188" class="LineNr">188 </span>    <span class="Delimiter">{</span>
+<span id="L189" class="LineNr">189 </span>      <span class="PreProc">break-if-&gt;=</span>
+<span id="L190" class="LineNr">190 </span>      num-trailers <span class="SpecialChar">&lt;-</span> copy <span class="Constant">2</span>
+<span id="L191" class="LineNr">191 </span>      <span class="PreProc">break</span> $read-grapheme:compute-length
+<span id="L192" class="LineNr">192 </span>    <span class="Delimiter">}</span>
+<span id="L193" class="LineNr">193 </span>    <span class="Comment"># 4 bytes</span>
+<span id="L194" class="LineNr">194 </span>    compare c, <span class="Constant">0xf8</span>
+<span id="L195" class="LineNr">195 </span>    <span class="Delimiter">{</span>
+<span id="L196" class="LineNr">196 </span>      <span class="PreProc">break-if-&gt;=</span>
+<span id="L197" class="LineNr">197 </span>      num-trailers <span class="SpecialChar">&lt;-</span> copy <span class="Constant">3</span>
+<span id="L198" class="LineNr">198 </span>      <span class="PreProc">break</span> $read-grapheme:compute-length
+<span id="L199" class="LineNr">199 </span>    <span class="Delimiter">}</span>
+<span id="L200" class="LineNr">200 </span>$read-grapheme:abort: <span class="Delimiter">{</span>
+<span id="L201" class="LineNr">201 </span>      <span class="Comment"># TODO: print to stderr</span>
+<span id="L202" class="LineNr">202 </span>      <a href='304screen.subx.html#L122'>print-string-to-real-screen</a> <span class="Constant">&quot;utf-8 encodings larger than 4 bytes are not supported. First byte seen: &quot;</span>
+<span id="L203" class="LineNr">203 </span>      <span class="PreProc">var</span> n/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L204" class="LineNr">204 </span>      <a href='304screen.subx.html#L213'>print-int32-hex-to-real-screen</a> n
+<span id="L205" class="LineNr">205 </span>      <a href='304screen.subx.html#L122'>print-string-to-real-screen</a> <span class="Constant">&quot;\n&quot;</span>
+<span id="L206" class="LineNr">206 </span>      <span class="PreProc">var</span> exit-status/<span class="Constant">ebx</span>: int <span class="SpecialChar">&lt;-</span> copy <span class="Constant">1</span>
+<span id="L207" class="LineNr">207 </span>      syscall_exit
+<span id="L208" class="LineNr">208 </span>    <span class="Delimiter">}</span>
+<span id="L209" class="LineNr">209 </span>  <span class="Delimiter">}</span>
+<span id="L210" class="LineNr">210 </span>  <span class="Comment"># prepend trailer bytes</span>
+<span id="L211" class="LineNr">211 </span>  <span class="PreProc">var</span> result/<span class="Constant">edi</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L212" class="LineNr">212 </span>  <span class="PreProc">var</span> num-byte-shifts/<span class="Constant">edx</span>: int <span class="SpecialChar">&lt;-</span> copy <span class="Constant">1</span>
+<span id="L213" class="LineNr">213 </span>  <span class="Delimiter">{</span>
+<span id="L214" class="LineNr">214 </span>    compare num-trailers, <span class="Constant">0</span>
+<span id="L215" class="LineNr">215 </span>    <span class="PreProc">break-if-&lt;=</span>
+<span id="L216" class="LineNr">216 </span>    <span class="PreProc">var</span> tmp/<span class="Constant">eax</span>: byte <span class="SpecialChar">&lt;-</span> <a href='112read-byte.subx.html#L273'>read-byte</a> in
+<span id="L217" class="LineNr">217 </span>    <span class="PreProc">var</span> tmp2/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy tmp
+<span id="L218" class="LineNr">218 </span>    tmp2 <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L257'>shift-left-bytes</a> tmp2, num-byte-shifts
+<span id="L219" class="LineNr">219 </span>    result <span class="SpecialChar">&lt;-</span> or tmp2
+<span id="L220" class="LineNr">220 </span>    <span class="Comment"># update loop state</span>
+<span id="L221" class="LineNr">221 </span>    num-byte-shifts <span class="SpecialChar">&lt;-</span> increment
+<span id="L222" class="LineNr">222 </span>    num-trailers <span class="SpecialChar">&lt;-</span> decrement
+<span id="L223" class="LineNr">223 </span>    <span class="PreProc">loop</span>
+<span id="L224" class="LineNr">224 </span>  <span class="Delimiter">}</span>
+<span id="L225" class="LineNr">225 </span>  out <span class="SpecialChar">&lt;-</span> copy result
+<span id="L226" class="LineNr">226 </span><span class="Delimiter">}</span>
+<span id="L227" class="LineNr">227 </span><span class="Delimiter">}</span>
+<span id="L228" class="LineNr">228 </span>
+<span id="L229" class="LineNr">229 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L229'>test-read-grapheme</a></span> <span class="Delimiter">{</span>
+<span id="L230" class="LineNr">230 </span>  <span class="PreProc">var</span> s: (stream byte <span class="Constant">0x30</span>)
+<span id="L231" class="LineNr">231 </span>  <span class="PreProc">var</span> s2/<span class="Constant">ecx</span>: (addr stream byte) <span class="SpecialChar">&lt;-</span> address s
+<span id="L232" class="LineNr">232 </span>  <a href='108write.subx.html#L24'>write</a> s2, <span class="Constant">&quot;aΒc世d界e&quot;</span>
+<span id="L233" class="LineNr">233 </span>  <span class="PreProc">var</span> c/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L160'>read-grapheme</a> s2
+<span id="L234" class="LineNr">234 </span>  <span class="PreProc">var</span> n/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L235" class="LineNr">235 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> n, <span class="Constant">0x61</span>, <span class="Constant">&quot;F - test grapheme/0&quot;</span>
+<span id="L236" class="LineNr">236 </span>  <span class="PreProc">var</span> c/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L160'>read-grapheme</a> s2
+<span id="L237" class="LineNr">237 </span>  <span class="PreProc">var</span> n/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L238" class="LineNr">238 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> n, <span class="Constant">0x92ce</span>, <span class="Constant">&quot;F - test grapheme/1&quot;</span>  <span class="Comment"># greek capital letter beta</span>
+<span id="L239" class="LineNr">239 </span>  <span class="PreProc">var</span> c/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L160'>read-grapheme</a> s2
+<span id="L240" class="LineNr">240 </span>  <span class="PreProc">var</span> n/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L241" class="LineNr">241 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> n, <span class="Constant">0x63</span>, <span class="Constant">&quot;F - test grapheme/2&quot;</span>
+<span id="L242" class="LineNr">242 </span>  <span class="PreProc">var</span> c/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L160'>read-grapheme</a> s2
+<span id="L243" class="LineNr">243 </span>  <span class="PreProc">var</span> n/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L244" class="LineNr">244 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> n, <span class="Constant">0x96b8e4</span>, <span class="Constant">&quot;F - test grapheme/3&quot;</span>
+<span id="L245" class="LineNr">245 </span>  <span class="PreProc">var</span> c/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L160'>read-grapheme</a> s2
+<span id="L246" class="LineNr">246 </span>  <span class="PreProc">var</span> n/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L247" class="LineNr">247 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> n, <span class="Constant">0x64</span>, <span class="Constant">&quot;F - test grapheme/4&quot;</span>
+<span id="L248" class="LineNr">248 </span>  <span class="PreProc">var</span> c/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L160'>read-grapheme</a> s2
+<span id="L249" class="LineNr">249 </span>  <span class="PreProc">var</span> n/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L250" class="LineNr">250 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> n, <span class="Constant">0x8c95e7</span>, <span class="Constant">&quot;F - test grapheme/5&quot;</span>
+<span id="L251" class="LineNr">251 </span>  <span class="PreProc">var</span> c/<span class="Constant">eax</span>: grapheme <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L160'>read-grapheme</a> s2
+<span id="L252" class="LineNr">252 </span>  <span class="PreProc">var</span> n/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> copy c
+<span id="L253" class="LineNr">253 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> n, <span class="Constant">0x65</span>, <span class="Constant">&quot;F - test grapheme/6&quot;</span>
+<span id="L254" class="LineNr">254 </span><span class="Delimiter">}</span>
+<span id="L255" class="LineNr">255 </span>
+<span id="L256" class="LineNr">256 </span><span class="Comment"># needed because available primitives only shift by a literal/constant number of bits</span>
+<span id="L257" class="LineNr">257 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='403unicode.mu.html#L257'>shift-left-bytes</a></span> n: int, k: int<span class="PreProc"> -&gt; </span>result/<span class="Constant">eax</span>: int <span class="Delimiter">{</span>
+<span id="L258" class="LineNr">258 </span>  <span class="PreProc">var</span> i/<span class="Constant">ecx</span>: int <span class="SpecialChar">&lt;-</span> copy <span class="Constant">0</span>
+<span id="L259" class="LineNr">259 </span>  result <span class="SpecialChar">&lt;-</span> copy n
+<span id="L260" class="LineNr">260 </span>  <span class="Delimiter">{</span>
+<span id="L261" class="LineNr">261 </span>    compare i, k
+<span id="L262" class="LineNr">262 </span>    <span class="PreProc">break-if-&gt;=</span>
+<span id="L263" class="LineNr">263 </span>    compare i, <span class="Constant">4</span>  <span class="Comment"># only 4 bytes in 32 bits</span>
+<span id="L264" class="LineNr">264 </span>    <span class="PreProc">break-if-&gt;=</span>
+<span id="L265" class="LineNr">265 </span>    result <span class="SpecialChar">&lt;-</span> shift-left <span class="Constant">8</span>
+<span id="L266" class="LineNr">266 </span>    i <span class="SpecialChar">&lt;-</span> increment
+<span id="L267" class="LineNr">267 </span>    <span class="PreProc">loop</span>
+<span id="L268" class="LineNr">268 </span>  <span class="Delimiter">}</span>
+<span id="L269" class="LineNr">269 </span><span class="Delimiter">}</span>
+<span id="L270" class="LineNr">270 </span>
+<span id="L271" class="LineNr">271 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L271'>test-shift-left-bytes-0</a></span> <span class="Delimiter">{</span>
+<span id="L272" class="LineNr">272 </span>  <span class="PreProc">var</span> result/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L257'>shift-left-bytes</a> <span class="Constant">1</span>, <span class="Constant">0</span>
+<span id="L273" class="LineNr">273 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> result, <span class="Constant">1</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L257'>shift-left-bytes</a> 0&quot;</span>
+<span id="L274" class="LineNr">274 </span><span class="Delimiter">}</span>
+<span id="L275" class="LineNr">275 </span>
+<span id="L276" class="LineNr">276 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L276'>test-shift-left-bytes-1</a></span> <span class="Delimiter">{</span>
+<span id="L277" class="LineNr">277 </span>  <span class="PreProc">var</span> result/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L257'>shift-left-bytes</a> <span class="Constant">1</span>, <span class="Constant">1</span>
+<span id="L278" class="LineNr">278 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> result, <span class="Constant">0x100</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L257'>shift-left-bytes</a> 1&quot;</span>
+<span id="L279" class="LineNr">279 </span><span class="Delimiter">}</span>
+<span id="L280" class="LineNr">280 </span>
+<span id="L281" class="LineNr">281 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L281'>test-shift-left-bytes-2</a></span> <span class="Delimiter">{</span>
+<span id="L282" class="LineNr">282 </span>  <span class="PreProc">var</span> result/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L257'>shift-left-bytes</a> <span class="Constant">1</span>, <span class="Constant">2</span>
+<span id="L283" class="LineNr">283 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> result, <span class="Constant">0x10000</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L257'>shift-left-bytes</a> 2&quot;</span>
+<span id="L284" class="LineNr">284 </span><span class="Delimiter">}</span>
+<span id="L285" class="LineNr">285 </span>
+<span id="L286" class="LineNr">286 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L286'>test-shift-left-bytes-3</a></span> <span class="Delimiter">{</span>
+<span id="L287" class="LineNr">287 </span>  <span class="PreProc">var</span> result/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L257'>shift-left-bytes</a> <span class="Constant">1</span>, <span class="Constant">3</span>
+<span id="L288" class="LineNr">288 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> result, <span class="Constant">0x1000000</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L257'>shift-left-bytes</a> 3&quot;</span>
+<span id="L289" class="LineNr">289 </span><span class="Delimiter">}</span>
+<span id="L290" class="LineNr">290 </span>
+<span id="L291" class="LineNr">291 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L291'>test-shift-left-bytes-4</a></span> <span class="Delimiter">{</span>
+<span id="L292" class="LineNr">292 </span>  <span class="PreProc">var</span> result/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L257'>shift-left-bytes</a> <span class="Constant">1</span>, <span class="Constant">4</span>
+<span id="L293" class="LineNr">293 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> result, <span class="Constant">0</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L257'>shift-left-bytes</a> 4&quot;</span>
+<span id="L294" class="LineNr">294 </span><span class="Delimiter">}</span>
+<span id="L295" class="LineNr">295 </span>
+<span id="L296" class="LineNr">296 </span><span class="PreProc">fn</span> <span class="muTest"><a href='403unicode.mu.html#L296'>test-shift-left-bytes-5</a></span> <span class="Delimiter">{</span>
+<span id="L297" class="LineNr">297 </span>  <span class="PreProc">var</span> result/<span class="Constant">eax</span>: int <span class="SpecialChar">&lt;-</span> <a href='403unicode.mu.html#L257'>shift-left-bytes</a> <span class="Constant">1</span>, <span class="Constant">5</span>
+<span id="L298" class="LineNr">298 </span>  <a href='102test.subx.html#L23'>check-ints-equal</a> result, <span class="Constant">0</span>, <span class="Constant">&quot;F - <a href='403unicode.mu.html#L257'>shift-left-bytes</a> &gt;4&quot;</span>
+<span id="L299" class="LineNr">299 </span><span class="Delimiter">}</span>
+<span id="L300" class="LineNr">300 </span>
+<span id="L301" class="LineNr">301 </span><span class="Comment"># To run all tests, uncomment this and run:</span>
+<span id="L302" class="LineNr">302 </span><span class="Comment">#   $ ./translate_mu  &amp;&amp;  ./a.elf</span>
+<span id="L303" class="LineNr">303 </span><span class="CommentedCode">#? fn main -&gt; r/ebx: int {</span>
+<span id="L304" class="LineNr">304 </span><span class="CommentedCode">#?   run-tests</span>
+<span id="L305" class="LineNr">305 </span><span class="CommentedCode">#?   r &lt;- copy 0</span>
+<span id="L306" class="LineNr">306 </span><span class="CommentedCode">#? }</span>
+</pre>
+</body>
+</html>
+<!-- vim: set foldmethod=manual : -->