mu/html/mu-init.subx.html

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<a href='https://github.com/akkartik/mu/blob/master/mu-init.subx'>https://github.com/akkartik/mu/blob/master/mu-init.subx</a>
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<span id="L1" class="LineNr"> 1 </span><span class="subxComment"># Initialize the minimal runtime for Mu programs.</span>
<span id="L2" class="LineNr"> 2 </span><span class="subxComment">#</span>
<span id="L3" class="LineNr"> 3 </span><span class="subxComment"># See translate_mu for how this file is used.</span>
<span id="L4" class="LineNr"> 4 </span><span class="subxComment">#</span>
<span id="L5" class="LineNr"> 5 </span><span class="subxComment"># Mu programs start at a function called 'main' with this signature:</span>
<span id="L6" class="LineNr"> 6 </span><span class="subxComment"># fn main args: (addr array addr array byte) -&gt; _/ebx: int</span>
<span id="L7" class="LineNr"> 7 </span><span class="subxComment"># If your program doesn't need commandline arguments you can drop it:</span>
<span id="L8" class="LineNr"> 8 </span><span class="subxComment"># fn main -&gt; _/ebx: int</span>
<span id="L9" class="LineNr"> 9 </span><span class="subxComment">#</span>
<span id="L10" class="LineNr">10 </span><span class="subxComment"># Notice that the output must be in ebx, so that the exit() syscall can pick</span>
<span id="L11" class="LineNr">11 </span><span class="subxComment"># it up.</span>
<span id="L12" class="LineNr">12 </span>
<span id="L13" class="LineNr">13 </span>== code
<span id="L14" class="LineNr">14 </span>
<span id="L15" class="LineNr">15 </span><span class="SpecialChar">Entry</span>:
<span id="L16" class="LineNr">16 </span> <span class="subxComment"># we don't use ebp in Entry; just initialize it</span>
<span id="L17" class="LineNr">17 </span> bd/copy-to-ebp 0/imm32
<span id="L18" class="LineNr">18 </span> <span class="subxH1Comment"># - save argc and argv</span>
<span id="L19" class="LineNr">19 </span> <span class="subxComment"># var argc-and-argv/esi</span>
<span id="L20" class="LineNr">20 </span> 89/&lt;- %esi 4/r32/esp
<span id="L21" class="LineNr">21 </span><span class="Constant">$Entry:initialize-heap</span>:
<span id="L22" class="LineNr">22 </span> <span class="subxH1Comment"># - initialize the heap</span>
<span id="L23" class="LineNr">23 </span> (<a href='104new-segment.subx.html#L40'>new-segment</a> *<span class="SpecialChar"><a href='120allocate.subx.html#L34'>Heap-size</a></span> <span class="SpecialChar"><a href='120allocate.subx.html#L27'>Heap</a></span>)
<span id="L24" class="LineNr">24 </span><span class="Constant">$Entry:initialize-args</span>:
<span id="L25" class="LineNr">25 </span> <span class="subxH1Comment"># - convert argv from null-terminated 'kernel' strings to length-prefixed Mu strings</span>
<span id="L26" class="LineNr">26 </span> <span class="subxComment"># var argc/edx: int</span>
<span id="L27" class="LineNr">27 </span> 8b/-&gt; *esi 2/r32/edx
<span id="L28" class="LineNr">28 </span> <span class="subxComment"># argc is in words; convert it to bytes</span>
<span id="L29" class="LineNr">29 </span> c1/shift 4/subop/left %edx 2/imm8
<span id="L30" class="LineNr">30 </span> <span class="subxComment"># var tmp/ebx: handle</span>
<span id="L31" class="LineNr">31 </span> 68/push 0/imm32
<span id="L32" class="LineNr">32 </span> 68/push 0/imm32
<span id="L33" class="LineNr">33 </span> 89/&lt;- %ebx 4/r32/esp
<span id="L34" class="LineNr">34 </span> <span class="subxComment"># var args/edi: (addr array (addr array byte))</span>
<span id="L35" class="LineNr">35 </span> (<a href='120allocate.subx.html#L576'>allocate-array</a> <span class="SpecialChar"><a href='120allocate.subx.html#L27'>Heap</a></span> %edx %ebx)
<span id="L36" class="LineNr">36 </span> (<a href='120allocate.subx.html#L256'>lookup</a> *ebx *(ebx+4)) <span class="subxComment"># =&gt; eax</span>
<span id="L37" class="LineNr">37 </span> 89/&lt;- %edi 0/r32/eax
<span id="L38" class="LineNr">38 </span> <span class="subxComment"># var curr/ecx: (addr kernel-string) = argv</span>
<span id="L39" class="LineNr">39 </span> 8d/copy-address *(esi+4) 1/r32/ecx
<span id="L40" class="LineNr">40 </span> <span class="subxComment"># var max/edx: (addr kernel-string) = argv+4+argc</span>
<span id="L41" class="LineNr">41 </span> 8d/copy-address *(ecx+edx) 2/r32/edx
<span id="L42" class="LineNr">42 </span> <span class="subxComment"># var dest/esi: (addr (addr array byte)) = args+4</span>
<span id="L43" class="LineNr">43 </span> 8d/copy-address *(edi+4) 6/r32/esi
<span id="L44" class="LineNr">44 </span> {
<span id="L45" class="LineNr">45 </span> <span class="subxComment"># if (curr &gt;= max) break</span>
<span id="L46" class="LineNr">46 </span> 39/compare %ecx 2/r32/edx
<span id="L47" class="LineNr">47 </span> 73/jump-if-addr&gt;= <span class="Constant">break</span>/disp8
<span id="L48" class="LineNr">48 </span> <span class="subxComment"># *dest = kernel-string-to-string(*curr)</span>
<span id="L49" class="LineNr">49 </span> (<a href='303kernel-string.subx.html#L7'>kernel-string-to-string</a> <span class="SpecialChar"><a href='120allocate.subx.html#L27'>Heap</a></span> *ecx %ebx)
<span id="L50" class="LineNr">50 </span> (<a href='120allocate.subx.html#L256'>lookup</a> *ebx *(ebx+4)) <span class="subxComment"># =&gt; eax</span>
<span id="L51" class="LineNr">51 </span> 89/&lt;- *esi 0/r32/eax
<span id="L52" class="LineNr">52 </span> <span class="subxComment"># curr += 4</span>
<span id="L53" class="LineNr">53 </span> 81 0/subop/add %ecx 4/imm32
<span id="L54" class="LineNr">54 </span> <span class="subxComment"># dest += 4</span>
<span id="L55" class="LineNr">55 </span> 81 0/subop/add %esi 4/imm32
<span id="L56" class="LineNr">56 </span> <span class="subxComment">#</span>
<span id="L57" class="LineNr">57 </span> eb/jump <span class="Constant">loop</span>/disp8
<span id="L58" class="LineNr">58 </span> }
<span id="L59" class="LineNr">59 </span> <span class="subxH1Comment"># - run Mu program</span>
<span id="L60" class="LineNr">60 </span> (main %edi) <span class="subxComment"># =&gt; ebx</span>
<span id="L61" class="LineNr">61 </span> <span class="subxH1Comment"># - exit</span>
<span id="L62" class="LineNr">62 </span> (syscall_exit)
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