<!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 - 053new-segment.subx</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,no_foldcolumn,expand_tabs,line_ids,prevent_copy=">
<meta name="colorscheme" content="minimal-light">
<style type="text/css">
<!--
pre { 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; }
.subxComment { color: #005faf; }
.subxS2Comment { color: #8a8a8a; }
.subxFunction { color: #af5f00; text-decoration: underline; }
.LineNr { }
.subxS1Comment { color: #0000af; }
.SpecialChar { color: #d70000; }
.Normal { color: #000000; background-color: #c6c6c6; padding-bottom: 1px; }
.subxMinorFunction { color: #875f5f; }
.Constant { color: #008787; }
-->
</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/053new-segment.subx'>https://github.com/akkartik/mu/blob/master/053new-segment.subx</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr"> 1 </span><span class="subxComment"># Create a new segment (pool of memory for allocating chunks from) in the form</span>
<span id="L2" class="LineNr"> 2 </span><span class="subxComment"># of an *allocation descriptor* that can be passed to the memory allocator</span>
<span id="L3" class="LineNr"> 3 </span><span class="subxComment"># (defined in a later layer).</span>
<span id="L4" class="LineNr"> 4 </span><span class="subxComment">#</span>
<span id="L5" class="LineNr"> 5 </span><span class="subxComment"># Currently an allocation descriptor consists of just the bounds of the pool of</span>
<span id="L6" class="LineNr"> 6 </span><span class="subxComment"># available memory:</span>
<span id="L7" class="LineNr"> 7 </span><span class="subxComment">#</span>
<span id="L8" class="LineNr"> 8 </span><span class="subxComment"># curr: address</span>
<span id="L9" class="LineNr"> 9 </span><span class="subxComment"># end: address</span>
<span id="L10" class="LineNr">10 </span><span class="subxComment">#</span>
<span id="L11" class="LineNr">11 </span><span class="subxComment"># This isn't enough information to reclaim individual allocations. We can't</span>
<span id="L12" class="LineNr">12 </span><span class="subxComment"># support arbitrary reclamation yet.</span>
<span id="L13" class="LineNr">13 </span>
<span id="L14" class="LineNr">14 </span>== code
<span id="L15" class="LineNr">15 </span><span class="subxComment"># instruction effective address register displacement immediate</span>
<span id="L16" class="LineNr">16 </span><span class="subxS1Comment"># . op subop mod rm32 base index scale r32</span>
<span id="L17" class="LineNr">17 </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="L18" class="LineNr">18 </span>
<span id="L19" class="LineNr">19 </span><span class="SpecialChar">Entry</span>: <span class="subxComment"># manual test</span>
<span id="L20" class="LineNr">20 </span> <span class="subxComment"># var ad/ecx: allocation-descriptor</span>
<span id="L21" class="LineNr">21 </span> 68/push 0/imm32/limit
<span id="L22" class="LineNr">22 </span> 68/push 0/imm32/curr
<span id="L23" class="LineNr">23 </span> 89/copy 3/mod/direct 1/rm32/ecx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 4/r32/esp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="subxComment"># copy esp to ecx</span>
<span id="L24" class="LineNr">24 </span> <span class="subxComment"># new-segment(0x1000, ad)</span>
<span id="L25" class="LineNr">25 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L26" class="LineNr">26 </span> 51/push-ecx
<span id="L27" class="LineNr">27 </span> 68/push 0x1000/imm32
<span id="L28" class="LineNr">28 </span> <span class="subxS2Comment"># . . call</span>
<span id="L29" class="LineNr">29 </span> e8/call <a href='053new-segment.subx.html#L41'>new-segment</a>/disp32
<span id="L30" class="LineNr">30 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L31" class="LineNr">31 </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="L32" class="LineNr">32 </span> <span class="subxComment"># var eax: (addr _) = ad->curr</span>
<span id="L33" class="LineNr">33 </span> 8b/copy 0/mod/indirect 1/rm32/ecx <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 *ecx to eax</span>
<span id="L34" class="LineNr">34 </span> <span class="subxComment"># write to *eax to check that we have access to the newly-allocated segment</span>
<span id="L35" class="LineNr">35 </span> c7 0/subop/copy 0/mod/direct 0/rm32/eax <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 0x34/imm32 <span class="subxComment"># copy to *eax</span>
<span id="L36" class="LineNr">36 </span> <span class="subxComment"># syscall(exit, eax)</span>
<span id="L37" class="LineNr">37 </span> 89/copy 3/mod/direct 3/rm32/ebx <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 ebx</span>
<span id="L38" class="LineNr">38 </span> b8/copy-to-eax 1/imm32/exit
<span id="L39" class="LineNr">39 </span> cd/syscall 0x80/imm8
<span id="L40" class="LineNr">40 </span>
<span id="L41" class="LineNr">41 </span><span class="subxFunction">new-segment</span>: <span class="subxComment"># len: int, ad: (addr allocation-descriptor)</span>
<span id="L42" class="LineNr">42 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L43" class="LineNr">43 </span> 55/push-ebp
<span id="L44" class="LineNr">44 </span> 89/copy 3/mod/direct 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 4/r32/esp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="subxComment"># copy esp to ebp</span>
<span id="L45" class="LineNr">45 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L46" class="LineNr">46 </span> 50/push-eax
<span id="L47" class="LineNr">47 </span> 53/push-ebx
<span id="L48" class="LineNr">48 </span> <span class="subxComment"># copy len to _mmap-new-segment->len</span>
<span id="L49" class="LineNr">49 </span> 8b/copy 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 0/r32/eax 8/disp8 <span class="Normal"> . </span> <span class="subxComment"># copy *(ebp+8) to eax</span>
<span id="L50" class="LineNr">50 </span> 89/copy 0/mod/indirect 5/rm32/.disp32 <span class="Normal"> . </span> <span class="Normal"> . </span> 0/r32/eax $_mmap-new-segment:len/disp32 <span class="subxComment"># copy eax to *$_mmap-new-segment:len</span>
<span id="L51" class="LineNr">51 </span> <span class="subxComment"># mmap(_mmap-new-segment)</span>
<span id="L52" class="LineNr">52 </span> bb/copy-to-ebx <a href='053new-segment.subx.html#L75'>_mmap-new-segment</a>/imm32
<span id="L53" class="LineNr">53 </span> b8/copy-to-eax 0x5a/imm32/mmap
<span id="L54" class="LineNr">54 </span> cd/syscall 0x80/imm8
<span id="L55" class="LineNr">55 </span> <span class="subxComment"># copy {eax, eax+len} to *ad</span>
<span id="L56" class="LineNr">56 </span> <span class="subxS1Comment"># . ebx = ad</span>
<span id="L57" class="LineNr">57 </span> 8b/copy 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 3/r32/ebx 0xc/disp8 <span class="Normal"> . </span> <span class="subxComment"># copy *(ebp+12) to ebx</span>
<span id="L58" class="LineNr">58 </span> <span class="subxS1Comment"># . ad->curr = eax</span>
<span id="L59" class="LineNr">59 </span> 89/copy 0/mod/indirect 3/rm32/ebx <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 *ebx</span>
<span id="L60" class="LineNr">60 </span> <span class="subxS1Comment"># . ad->end = eax+len</span>
<span id="L61" class="LineNr">61 </span> 03/add 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 0/r32/eax 8/disp8 <span class="Normal"> . </span> <span class="subxComment"># add *(ebp+8) to eax</span>
<span id="L62" class="LineNr">62 </span> 89/copy 1/mod/*+disp8 3/rm32/ebx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 0/r32/eax 4/disp8 <span class="Normal"> . </span> <span class="subxComment"># copy eax to *(ebx+4)</span>
<span id="L63" class="LineNr">63 </span><span class="Constant">$new-segment:end</span>:
<span id="L64" class="LineNr">64 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L65" class="LineNr">65 </span> 5b/pop-to-ebx
<span id="L66" class="LineNr">66 </span> 58/pop-to-eax
<span id="L67" class="LineNr">67 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L68" class="LineNr">68 </span> 89/copy 3/mod/direct 4/rm32/esp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 5/r32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="subxComment"># copy ebp to esp</span>
<span id="L69" class="LineNr">69 </span> 5d/pop-to-ebp
<span id="L70" class="LineNr">70 </span> c3/return
<span id="L71" class="LineNr">71 </span>
<span id="L72" class="LineNr">72 </span>== data
<span id="L73" class="LineNr">73 </span>
<span id="L74" class="LineNr">74 </span><span class="subxComment"># various constants used here were found in the Linux sources (search for file mman-common.h)</span>
<span id="L75" class="LineNr">75 </span><span class="subxMinorFunction">_mmap-new-segment</span>: <span class="subxComment"># mmap_arg_struct</span>
<span id="L76" class="LineNr">76 </span> <span class="subxComment"># addr</span>
<span id="L77" class="LineNr">77 </span> 0/imm32
<span id="L78" class="LineNr">78 </span><span class="Constant">$_mmap-new-segment:len</span>:
<span id="L79" class="LineNr">79 </span> <span class="subxComment"># len</span>
<span id="L80" class="LineNr">80 </span> 0/imm32
<span id="L81" class="LineNr">81 </span> <span class="subxComment"># protection flags</span>
<span id="L82" class="LineNr">82 </span> 3/imm32 <span class="subxComment"># PROT_READ | PROT_WRITE</span>
<span id="L83" class="LineNr">83 </span> <span class="subxComment"># sharing flags</span>
<span id="L84" class="LineNr">84 </span> 0x22/imm32 <span class="subxComment"># MAP_PRIVATE | MAP_ANONYMOUS</span>
<span id="L85" class="LineNr">85 </span> <span class="subxComment"># fd</span>
<span id="L86" class="LineNr">86 </span> -1/imm32 <span class="subxComment"># since MAP_ANONYMOUS is specified</span>
<span id="L87" class="LineNr">87 </span> <span class="subxComment"># offset</span>
<span id="L88" class="LineNr">88 </span> 0/imm32 <span class="subxComment"># since MAP_ANONYMOUS is specified</span>
<span id="L89" class="LineNr">89 </span>
<span id="L90" class="LineNr">90 </span><span class="subxS2Comment"># . . vim:nowrap:textwidth=0</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->