1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
<!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 - 080zero-out.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; }
.LineNr { }
.subxS1Comment { color: #0000af; }
.subxFunction { color: #af5f00; text-decoration: underline; }
.Normal { color: #000000; background-color: #c6c6c6; padding-bottom: 1px; }
.Constant { color: #008787; }
.subxTest { color: #5f8700; }
-->
</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/080zero-out.subx'>https://github.com/akkartik/mu/blob/master/080zero-out.subx</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr"> 1 </span><span class="subxComment"># Fill a region of memory with zeroes.</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">zero-out</span>: <span class="subxComment"># start : address, len : int</span>
<span id="L9" class="LineNr"> 9 </span> <span class="subxComment"># pseudocode:</span>
<span id="L10" class="LineNr">10 </span> <span class="subxComment"># curr/esi = start</span>
<span id="L11" class="LineNr">11 </span> <span class="subxComment"># i/ecx = 0</span>
<span id="L12" class="LineNr">12 </span> <span class="subxComment"># while true</span>
<span id="L13" class="LineNr">13 </span> <span class="subxComment"># if (i >= len) break</span>
<span id="L14" class="LineNr">14 </span> <span class="subxComment"># *curr = 0</span>
<span id="L15" class="LineNr">15 </span> <span class="subxComment"># ++curr</span>
<span id="L16" class="LineNr">16 </span> <span class="subxComment"># ++i</span>
<span id="L17" class="LineNr">17 </span> <span class="subxComment">#</span>
<span id="L18" class="LineNr">18 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L19" class="LineNr">19 </span> 55/push-ebp
<span id="L20" class="LineNr">20 </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="L21" class="LineNr">21 </span> <span class="subxS1Comment"># . save registers</span>
<span id="L22" class="LineNr">22 </span> 50/push-eax
<span id="L23" class="LineNr">23 </span> 51/push-ecx
<span id="L24" class="LineNr">24 </span> 52/push-edx
<span id="L25" class="LineNr">25 </span> 56/push-esi
<span id="L26" class="LineNr">26 </span> <span class="subxComment"># curr/esi = start</span>
<span id="L27" class="LineNr">27 </span> 8b/copy 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 6/r32/esi 8/disp8 <span class="Normal"> . </span> <span class="subxComment"># copy *(ebp+8) to esi</span>
<span id="L28" class="LineNr">28 </span> <span class="subxComment"># i/ecx = 0</span>
<span id="L29" class="LineNr">29 </span> 31/xor 3/mod/direct 1/rm32/ecx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 1/r32/ecx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="subxComment"># clear ecx</span>
<span id="L30" class="LineNr">30 </span> <span class="subxComment"># edx = len</span>
<span id="L31" class="LineNr">31 </span> 8b/copy 1/mod/*+disp8 5/rm32/ebp <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 2/r32/edx 0xc/disp8 <span class="Normal"> . </span> <span class="subxComment"># copy *(ebp+12) to edx</span>
<span id="L32" class="LineNr">32 </span><span class="Constant">$zero-out:loop</span>:
<span id="L33" class="LineNr">33 </span> <span class="subxComment"># if (i >= len) break</span>
<span id="L34" class="LineNr">34 </span> 39/compare 3/mod/direct 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"># compare ecx with edx</span>
<span id="L35" class="LineNr">35 </span> 7d/jump-if-greater-or-equal $zero-out:end/disp8
<span id="L36" class="LineNr">36 </span> <span class="subxComment"># *curr = 0</span>
<span id="L37" class="LineNr">37 </span> c6 0/subop/copy 0/mod/direct 6/rm32/esi <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> 0/imm8 <span class="subxComment"># copy byte to *esi</span>
<span id="L38" class="LineNr">38 </span> <span class="subxComment"># ++curr</span>
<span id="L39" class="LineNr">39 </span> 46/increment-esi
<span id="L40" class="LineNr">40 </span> <span class="subxComment"># ++i</span>
<span id="L41" class="LineNr">41 </span> 41/increment-ecx
<span id="L42" class="LineNr">42 </span> eb/jump $zero-out:<span class="Constant">loop</span>/disp8
<span id="L43" class="LineNr">43 </span><span class="Constant">$zero-out:end</span>:
<span id="L44" class="LineNr">44 </span> <span class="subxS1Comment"># . restore registers</span>
<span id="L45" class="LineNr">45 </span> 5e/pop-to-esi
<span id="L46" class="LineNr">46 </span> 5a/pop-to-edx
<span id="L47" class="LineNr">47 </span> 59/pop-to-ecx
<span id="L48" class="LineNr">48 </span> 58/pop-to-eax
<span id="L49" class="LineNr">49 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L50" class="LineNr">50 </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="L51" class="LineNr">51 </span> 5d/pop-to-ebp
<span id="L52" class="LineNr">52 </span> c3/return
<span id="L53" class="LineNr">53 </span>
<span id="L54" class="LineNr">54 </span><span class="subxTest">test-zero-out</span>:
<span id="L55" class="LineNr">55 </span> <span class="subxS1Comment"># . prologue</span>
<span id="L56" class="LineNr">56 </span> 55/push-ebp
<span id="L57" class="LineNr">57 </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="L58" class="LineNr">58 </span> <span class="subxComment"># region/ecx = 34, 35, 36, 37</span>
<span id="L59" class="LineNr">59 </span> 68/push 0x37363534/imm32
<span id="L60" class="LineNr">60 </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="L61" class="LineNr">61 </span> <span class="subxComment"># zero-out(ecx, 3)</span>
<span id="L62" class="LineNr">62 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L63" class="LineNr">63 </span> 68/push 3/imm32/len
<span id="L64" class="LineNr">64 </span> 51/push-ecx
<span id="L65" class="LineNr">65 </span> <span class="subxS2Comment"># . . call</span>
<span id="L66" class="LineNr">66 </span> e8/call <a href='080zero-out.subx.html#L8'>zero-out</a>/disp32
<span id="L67" class="LineNr">67 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L68" class="LineNr">68 </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="L69" class="LineNr">69 </span> <span class="subxComment"># first 3 bytes cleared, fourth left alone</span>
<span id="L70" class="LineNr">70 </span> <span class="subxS1Comment"># . check-ints-equal(*ecx, 0x37000000, msg)</span>
<span id="L71" class="LineNr">71 </span> <span class="subxS2Comment"># . . push args</span>
<span id="L72" class="LineNr">72 </span> 68/push <span class="Constant">"F - test-zero-out"</span>/imm32
<span id="L73" class="LineNr">73 </span> 68/push 0x37000000/imm32
<span id="L74" class="LineNr">74 </span> ff 6/subop/push 0/mod/indirect 1/rm32/ecx <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="Normal"> . </span> <span class="subxComment"># push *ecx</span>
<span id="L75" class="LineNr">75 </span> <span class="subxS2Comment"># . . call</span>
<span id="L76" class="LineNr">76 </span> e8/call <a href='051test.subx.html#L24'>check-ints-equal</a>/disp32
<span id="L77" class="LineNr">77 </span> <span class="subxS2Comment"># . . discard args</span>
<span id="L78" class="LineNr">78 </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="L79" class="LineNr">79 </span> <span class="subxS1Comment"># . epilogue</span>
<span id="L80" class="LineNr">80 </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="L81" class="LineNr">81 </span> 5d/pop-to-ebp
<span id="L82" class="LineNr">82 </span> c3/return
<span id="L83" class="LineNr">83 </span>
<span id="L84" class="LineNr">84 </span><span class="subxS2Comment"># . . vim:nowrap:textwidth=0</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->
|