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<title>Mu - linux/random.subx</title>
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* { font-size:12pt; font-size: 1em; }
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<a href='https://github.com/akkartik/mu/blob/main/linux/random.subx'>https://github.com/akkartik/mu/blob/main/linux/random.subx</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr"> 1 </span><span class="subxComment"># Repeatedly read 32-bit numbers from /dev/random, print them to stdout.</span>
<span id="L2" class="LineNr"> 2 </span><span class="subxComment">#</span>
<span id="L3" class="LineNr"> 3 </span><span class="subxComment"># To run:</span>
<span id="L4" class="LineNr"> 4 </span><span class="subxComment">#   $ bootstrap/bootstrap translate [01]*.subx random.subx -o random</span>
<span id="L5" class="LineNr"> 5 </span><span class="subxComment">#   $ bootstrap/bootstrap run random</span>
<span id="L6" class="LineNr"> 6 </span>
<span id="L7" class="LineNr"> 7 </span>== code 0x09000000
<span id="L8" class="LineNr"> 8 </span><span class="subxComment">#   instruction                     effective address                                                   register    displacement    immediate</span>
<span id="L9" class="LineNr"> 9 </span><span class="subxS1Comment"># . op          subop               mod             rm32          base        index         scale       r32</span>
<span id="L10" class="LineNr">10 </span><span class="subxS1Comment"># . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes</span>
<span id="L11" class="LineNr">11 </span>
<span id="L12" class="LineNr">12 </span><span class="SpecialChar">Entry</span>:
<span id="L13" class="LineNr">13 </span>    <span class="subxComment"># stream/esi = syscall(open, &quot;/dev/null&quot;, O_RDONLY, 0)  # we can't use 'fd' because it looks like a hex byte</span>
<span id="L14" class="LineNr">14 </span>    bb/copy-to-ebx  <span class="SpecialChar"><a href='random.subx.html#L55'>Filename</a></span>/imm32
<span id="L15" class="LineNr">15 </span>    b9/copy-to-ecx  0/imm32/rdonly
<span id="L16" class="LineNr">16 </span>    ba/copy-to-edx  0x180/imm32/fixed-perms
<span id="L17" class="LineNr">17 </span>    e8/call  <a href='000init.subx.html#L35'>syscall_open</a>/disp32
<span id="L18" class="LineNr">18 </span>    <span class="subxS1Comment"># . stream = eax</span>
<span id="L19" class="LineNr">19 </span>    89/copy                         3/mod/direct    6/rm32/esi   <span class="Normal"> . </span>         <span class="Normal"> . </span>           <span class="Normal"> . </span>          0/r32/eax  <span class="Normal"> . </span>             <span class="Normal"> . </span>                <span class="subxComment"># copy eax to esi</span>
<span id="L20" class="LineNr">20 </span>
<span id="L21" class="LineNr">21 </span><span class="Constant">$loop</span>:
<span id="L22" class="LineNr">22 </span>
<span id="L23" class="LineNr">23 </span>    <span class="subxComment"># syscall(read, Stream, N, 4)</span>
<span id="L24" class="LineNr">24 </span>    89/copy                         3/mod/direct    3/rm32/ebx   <span class="Normal"> . </span>         <span class="Normal"> . </span>           <span class="Normal"> . </span>          6/r32/esi  <span class="Normal"> . </span>             <span class="Normal"> . </span>                <span class="subxComment"># copy esi to ebx</span>
<span id="L25" class="LineNr">25 </span>    b9/copy-to-ecx  <span class="SpecialChar"><a href='random.subx.html#L53'>N</a></span>/imm32
<span id="L26" class="LineNr">26 </span>    ba/copy-to-edx  4/imm32/size
<span id="L27" class="LineNr">27 </span>    e8/call  <a href='000init.subx.html#L23'>syscall_read</a>/disp32
<span id="L28" class="LineNr">28 </span>
<span id="L29" class="LineNr">29 </span>    <span class="subxComment"># write-int32-hex-buffered(Stdout, *N)</span>
<span id="L30" class="LineNr">30 </span>    <span class="subxS2Comment"># . . push args</span>
<span id="L31" class="LineNr">31 </span>    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32           <span class="Normal"> . </span>           <span class="Normal"> . </span>         <span class="Normal"> . </span>          <span class="SpecialChar"><a href='random.subx.html#L53'>N</a></span>/disp32                          <span class="subxComment"># push *N</span>
<span id="L32" class="LineNr">32 </span>    68/push  <span class="SpecialChar"><a href='115write-byte.subx.html#L10'>Stdout</a></span>/imm32
<span id="L33" class="LineNr">33 </span>    <span class="subxS2Comment"># . . call</span>
<span id="L34" class="LineNr">34 </span>    e8/call  <a href='117write-int-hex.subx.html#L288'>write-int32-hex-buffered</a>/disp32
<span id="L35" class="LineNr">35 </span>
<span id="L36" class="LineNr">36 </span>    <span class="subxComment"># write-buffered(Stdout, Newline)</span>
<span id="L37" class="LineNr">37 </span>    <span class="subxS2Comment"># . . push args</span>
<span id="L38" class="LineNr">38 </span>    68/push  <span class="SpecialChar"><a href='102test.subx.html#L82'>Newline</a></span>/imm32
<span id="L39" class="LineNr">39 </span>    68/push  <span class="SpecialChar"><a href='115write-byte.subx.html#L10'>Stdout</a></span>/imm32
<span id="L40" class="LineNr">40 </span>    <span class="subxS2Comment"># . . call</span>
<span id="L41" class="LineNr">41 </span>    e8/call  <a href='116write-buffered.subx.html#L8'>write-buffered</a>/disp32
<span id="L42" class="LineNr">42 </span>    <span class="subxS2Comment"># . . discard args</span>
<span id="L43" class="LineNr">43 </span>    81          0/subop/add         3/mod/direct    4/rm32/esp   <span class="Normal"> . </span>         <span class="Normal"> . </span>           <span class="Normal"> . </span>         <span class="Normal"> . </span>         <span class="Normal"> . </span>              8/imm32           <span class="subxComment"># add to esp</span>
<span id="L44" class="LineNr">44 </span>
<span id="L45" class="LineNr">45 </span>    eb/jump  $loop/disp8
<span id="L46" class="LineNr">46 </span>
<span id="L47" class="LineNr">47 </span>    <span class="subxComment"># syscall(exit, 0)</span>
<span id="L48" class="LineNr">48 </span>    bb/copy-to-ebx  0/imm32
<span id="L49" class="LineNr">49 </span>    e8/call  <a href='000init.subx.html#L18'>syscall_exit</a>/disp32
<span id="L50" class="LineNr">50 </span>
<span id="L51" class="LineNr">51 </span>== data 0x0a000000
<span id="L52" class="LineNr">52 </span>
<span id="L53" class="LineNr">53 </span><span class="SpecialChar">N</span>:
<span id="L54" class="LineNr">54 </span>    0/imm32
<span id="L55" class="LineNr">55 </span><span class="SpecialChar">Filename</span>:
<span id="L56" class="LineNr">56 </span>    2f 64 65 76 2f 72 61 6e 64 6f 6d 00
<span id="L57" class="LineNr">57 </span><span class="subxComment">#   /  d  e  v  /  r  a  n  d  o  m  null</span>
<span id="L58" class="LineNr">58 </span>
<span id="L59" class="LineNr">59 </span><span class="subxS2Comment"># . . vim&#0058;nowrap:textwidth=0</span>
</pre>
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