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<a href='https://github.com/akkartik/mu/blob/main/121new-stream.subx'>https://github.com/akkartik/mu/blob/main/121new-stream.subx</a>
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<span id="L1" class="LineNr"> 1 </span><span class="subxComment"># Helper to allocate a stream on the heap.</span>
<span id="L2" class="LineNr"> 2 </span>
<span id="L3" class="LineNr"> 3 </span>== code
<span id="L4" class="LineNr"> 4 </span><span class="subxComment"># instruction effective address register displacement immediate</span>
<span id="L5" class="LineNr"> 5 </span><span class="subxS1Comment"># . op subop mod rm32 base index scale r32</span>
<span id="L6" class="LineNr"> 6 </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="L7" class="LineNr"> 7 </span>
<span id="L8" class="LineNr"> 8 </span><span class="subxFunction">new-stream</span>: <span class="subxComment"># ad: (addr allocation-descriptor), length: int, elemsize: int, out: (addr handle stream _)</span>
<span id="L9" class="LineNr"> 9 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L10" class="LineNr"> 10 </span> 55/push-ebp
<span id="L11" class="LineNr"> 11 </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="L12" class="LineNr"> 12 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L13" class="LineNr"> 13 </span> 50/push-eax
<span id="L14" class="LineNr"> 14 </span> 52/push-edx
<span id="L15" class="LineNr"> 15 </span> <span class="subxComment"># var size/edx: int = elemsize*length (clobbering eax)</span>
<span id="L16" class="LineNr"> 16 </span> <span class="subxS1Comment"># . eax = elemsize</span>
<span id="L17" class="LineNr"> 17 </span> 8b/copy 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 0/r32/eax 0x10/disp8 <span class="Normal"> . </span> <span class="subxComment"># copy *(ebp+16) to eax</span>
<span id="L18" class="LineNr"> 18 </span> <span class="subxS1Comment"># . eax *= length</span>
<span id="L19" class="LineNr"> 19 </span> 31/xor 3/mod/direct 2/rm32/edx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 2/r32/edx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="subxComment"># clear edx</span>
<span id="L20" class="LineNr"> 20 </span> f7 4/subop/multiply 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> 0xc/disp8 <span class="Normal"> . </span> <span class="subxComment"># multiply *(ebp+12) into edx:eax</span>
<span id="L21" class="LineNr"> 21 </span> <span class="subxS1Comment"># . if overflow abort</span>
<span id="L22" class="LineNr"> 22 </span> 81 7/subop/compare 3/mod/direct 2/rm32/edx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 0/imm32 <span class="subxComment"># compare edx</span>
<span id="L23" class="LineNr"> 23 </span> 75/jump-if-!= $new-stream:<a href='317abort.subx.html#L5'>abort</a>/disp8
<span id="L24" class="LineNr"> 24 </span> <span class="subxS1Comment"># . edx = elemsize*length</span>
<span id="L25" class="LineNr"> 25 </span> 89/copy 3/mod/direct 2/rm32/edx <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 edx</span>
<span id="L26" class="LineNr"> 26 </span> <span class="subxComment"># var n/eax: int = size + 12 (for read, write and size)</span>
<span id="L27" class="LineNr"> 27 </span> 05/add-to-eax 0xc/imm32
<span id="L28" class="LineNr"> 28 </span> <span class="subxComment"># allocate(ad, n, out)</span>
<span id="L29" class="LineNr"> 29 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L30" class="LineNr"> 30 </span> ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 0x14/disp8 <span class="Normal"> . </span> <span class="subxComment"># push *(ebp+20)</span>
<span id="L31" class="LineNr"> 31 </span> 50/push-eax
<span id="L32" class="LineNr"> 32 </span> ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 8/disp8 <span class="Normal"> . </span> <span class="subxComment"># push *(ebp+8)</span>
<span id="L33" class="LineNr"> 33 </span> <span class="subxS2Comment"># . . call</span>
<span id="L34" class="LineNr"> 34 </span> e8/call <a href='120allocate.subx.html#L43'>allocate</a>/disp32
<span id="L35" class="LineNr"> 35 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L36" class="LineNr"> 36 </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> 0xc/imm32 <span class="subxComment"># add to esp</span>
<span id="L37" class="LineNr"> 37 </span> <span class="subxComment"># eax = out->payload</span>
<span id="L38" class="LineNr"> 38 </span> 8b/copy 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 0/r32/eax 0x14/disp8 <span class="Normal"> . </span> <span class="subxComment"># copy *(ebp+20) to eax</span>
<span id="L39" class="LineNr"> 39 </span> 8b/copy 1/mod/*+disp8 0/rm32/eax <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+4) to eax</span>
<span id="L40" class="LineNr"> 40 </span> <span class="subxComment"># skip payload->allocid</span>
<span id="L41" class="LineNr"> 41 </span> 05/add-to-eax 4/imm32
<span id="L42" class="LineNr"> 42 </span> <span class="subxComment"># eax->size = size</span>
<span id="L43" class="LineNr"> 43 </span> 89/copy 1/mod/*+disp8 0/rm32/eax <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 2/r32/edx 8/disp8 <span class="Normal"> . </span> <span class="subxComment"># copy edx to *(eax+8)</span>
<span id="L44" class="LineNr"> 44 </span> <span class="subxComment"># clear-stream(eax)</span>
<span id="L45" class="LineNr"> 45 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L46" class="LineNr"> 46 </span> 50/push-eax
<span id="L47" class="LineNr"> 47 </span> <span class="subxS2Comment"># . . call</span>
<span id="L48" class="LineNr"> 48 </span> e8/call <a href='106stream.subx.html#L20'>clear-stream</a>/disp32
<span id="L49" class="LineNr"> 49 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L50" class="LineNr"> 50 </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> 4/imm32 <span class="subxComment"># add to esp</span>
<span id="L51" class="LineNr"> 51 </span><span class="Constant">$new-stream:end</span>:
<span id="L52" class="LineNr"> 52 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L53" class="LineNr"> 53 </span> 5a/pop-to-edx
<span id="L54" class="LineNr"> 54 </span> 58/pop-to-eax
<span id="L55" class="LineNr"> 55 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L56" class="LineNr"> 56 </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="L57" class="LineNr"> 57 </span> 5d/pop-to-ebp
<span id="L58" class="LineNr"> 58 </span> c3/return
<span id="L59" class="LineNr"> 59 </span>
<span id="L60" class="LineNr"> 60 </span><span class="Constant">$new-stream:<a href='317abort.subx.html#L5'>abort</a></span>:
<span id="L61" class="LineNr"> 61 </span> (<a href='317abort.subx.html#L5'>abort</a> <span class="Constant">"new-stream: size too large"</span>)
<span id="L62" class="LineNr"> 62 </span> <span class="subxComment"># never gets here</span>
<span id="L63" class="LineNr"> 63 </span>
<span id="L64" class="LineNr"> 64 </span><span class="subxTest">test-new-stream</span>:
<span id="L65" class="LineNr"> 65 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L66" class="LineNr"> 66 </span> 55/push-ebp
<span id="L67" class="LineNr"> 67 </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="L68" class="LineNr"> 68 </span> <span class="subxComment"># var ad/ecx: allocation-descriptor containing 16 bytes</span>
<span id="L69" class="LineNr"> 69 </span> <span class="subxS1Comment"># . var end/ecx: (addr byte)</span>
<span id="L70" class="LineNr"> 70 </span> 89/<- %ecx 4/r32/esp
<span id="L71" class="LineNr"> 71 </span> <span class="subxS1Comment"># . var start/edx: (addr byte) = end - 32</span>
<span id="L72" class="LineNr"> 72 </span> 81 5/subop/subtract %esp 0x20/imm32
<span id="L73" class="LineNr"> 73 </span> 89/<- %edx 4/r32/esp
<span id="L74" class="LineNr"> 74 </span> <span class="subxS1Comment"># . ad = {start, end}</span>
<span id="L75" class="LineNr"> 75 </span> 51/push-ecx
<span id="L76" class="LineNr"> 76 </span> 52/push-edx
<span id="L77" class="LineNr"> 77 </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="L78" class="LineNr"> 78 </span> <span class="subxComment"># var start/edx = ad->curr</span>
<span id="L79" class="LineNr"> 79 </span> 8b/copy 0/mod/indirect 1/rm32/ecx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 2/r32/edx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="subxComment"># copy *ecx to edx</span>
<span id="L80" class="LineNr"> 80 </span> <span class="subxComment"># var h/ebx: (handle stream byte)</span>
<span id="L81" class="LineNr"> 81 </span> 68/push 0/imm32
<span id="L82" class="LineNr"> 82 </span> 68/push 0/imm32
<span id="L83" class="LineNr"> 83 </span> 89/copy 3/mod/direct 3/rm32/ebx <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 ebx</span>
<span id="L84" class="LineNr"> 84 </span> <span class="subxComment"># new-stream(ad, 3, 2, h)</span>
<span id="L85" class="LineNr"> 85 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L86" class="LineNr"> 86 </span> 53/push-ebx
<span id="L87" class="LineNr"> 87 </span> 68/push 2/imm32
<span id="L88" class="LineNr"> 88 </span> 68/push 3/imm32
<span id="L89" class="LineNr"> 89 </span> 51/push-ecx
<span id="L90" class="LineNr"> 90 </span> <span class="subxS2Comment"># . . call</span>
<span id="L91" class="LineNr"> 91 </span> e8/call <a href='121new-stream.subx.html#L8'>new-stream</a>/disp32
<span id="L92" class="LineNr"> 92 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L93" class="LineNr"> 93 </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> 0x10/imm32 <span class="subxComment"># add to esp</span>
<span id="L94" class="LineNr"> 94 </span> <span class="subxComment"># eax = out->payload</span>
<span id="L95" class="LineNr"> 95 </span> 8b/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 *(ebx+4) to eax</span>
<span id="L96" class="LineNr"> 96 </span> <span class="subxComment"># check-ints-equal(eax, edx, msg)</span>
<span id="L97" class="LineNr"> 97 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L98" class="LineNr"> 98 </span> 68/push <span class="Constant">"F - <a href='121new-stream.subx.html#L64'>test-new-stream</a>: returns current pointer of allocation descriptor"</span>/imm32
<span id="L99" class="LineNr"> 99 </span> 52/push-edx
<span id="L100" class="LineNr">100 </span> 50/push-eax
<span id="L101" class="LineNr">101 </span> <span class="subxS2Comment"># . . call</span>
<span id="L102" class="LineNr">102 </span> e8/call <a href='502test.mu.html#L2'>check-ints-equal</a>/disp32
<span id="L103" class="LineNr">103 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L104" class="LineNr">104 </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> 0xc/imm32 <span class="subxComment"># add to esp</span>
<span id="L105" class="LineNr">105 </span> <span class="subxComment"># skip payload->allocid</span>
<span id="L106" class="LineNr">106 </span> 05/add-to-eax 4/imm32
<span id="L107" class="LineNr">107 </span> <span class="subxComment"># check-ints-equal(eax->size, 6, msg)</span>
<span id="L108" class="LineNr">108 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L109" class="LineNr">109 </span> 68/push <span class="Constant">"F - <a href='121new-stream.subx.html#L64'>test-new-stream</a>: sets size correctly"</span>/imm32
<span id="L110" class="LineNr">110 </span> 68/push 6/imm32
<span id="L111" class="LineNr">111 </span> ff 6/subop/push 1/mod/*+disp8 0/rm32/eax <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 8/disp8 <span class="subxComment"># push *(eax+8)</span>
<span id="L112" class="LineNr">112 </span> <span class="subxS2Comment"># . . call</span>
<span id="L113" class="LineNr">113 </span> e8/call <a href='502test.mu.html#L2'>check-ints-equal</a>/disp32
<span id="L114" class="LineNr">114 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L115" class="LineNr">115 </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> 0xc/imm32 <span class="subxComment"># add to esp</span>
<span id="L116" class="LineNr">116 </span> <span class="subxComment"># the rest is delegated to clear-stream() so we won't bother checking it</span>
<span id="L117" class="LineNr">117 </span> <span class="subxS1Comment"># . reclaim locals</span>
<span id="L118" class="LineNr">118 </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> 0x30/imm32 <span class="subxComment"># add to esp</span>
<span id="L119" class="LineNr">119 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L120" class="LineNr">120 </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="L121" class="LineNr">121 </span> 5d/pop-to-ebp
<span id="L122" class="LineNr">122 </span> c3/return
<span id="L123" class="LineNr">123 </span>
<span id="L124" class="LineNr">124 </span><span class="subxS2Comment"># . . vim:nowrap:textwidth=0</span>
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