about summary refs log tree commit diff stats
path: root/html/110stop.subx.html
blob: 81bc519484efeeb8724fcf5cb385d773e247c84b (plain) (blame)
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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
<!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 - 110stop.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 { }
.subxTest { color: #5f8700; }
.subxS1Comment { color: #0000af; }
.CommentedCode { color: #8a8a8a; }
.subxFunction { color: #af5f00; text-decoration: underline; }
.Normal { color: #000000; background-color: #c6c6c6; padding-bottom: 1px; }
.Constant { color: #008787; }
.subxMinorFunction { color: #875f5f; }
-->
</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/110stop.subx'>https://github.com/akkartik/mu/blob/master/110stop.subx</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr">  1 </span><span class="subxComment"># stop: dependency-injected wrapper around the exit() syscall</span>
<span id="L2" class="LineNr">  2 </span><span class="subxComment">#</span>
<span id="L3" class="LineNr">  3 </span><span class="subxComment"># We'd like to be able to write tests for functions that call exit(), and to</span>
<span id="L4" class="LineNr">  4 </span><span class="subxComment"># make assertions about whether they exit() or not in a given situation. To</span>
<span id="L5" class="LineNr">  5 </span><span class="subxComment"># achieve this we'll call exit() via a smarter wrapper called 'stop'.</span>
<span id="L6" class="LineNr">  6 </span><span class="subxComment">#</span>
<span id="L7" class="LineNr">  7 </span><span class="subxComment"># In the context of a test, calling a function X that calls 'stop' (directly</span>
<span id="L8" class="LineNr">  8 </span><span class="subxComment"># or through further intervening calls) will unwind the stack until X returns,</span>
<span id="L9" class="LineNr">  9 </span><span class="subxComment"># so that we can say check any further assertions after the execution of X. To</span>
<span id="L10" class="LineNr"> 10 </span><span class="subxComment"># achieve this end, we'll pass the return address of X as a 'target' argument</span>
<span id="L11" class="LineNr"> 11 </span><span class="subxComment"># into X, plumbing it through to 'stop'. When 'stop' gets a non-null target it</span>
<span id="L12" class="LineNr"> 12 </span><span class="subxComment"># unwinds the stack until the target. If it gets a null target it calls</span>
<span id="L13" class="LineNr"> 13 </span><span class="subxComment"># exit().</span>
<span id="L14" class="LineNr"> 14 </span><span class="subxComment">#</span>
<span id="L15" class="LineNr"> 15 </span><span class="subxComment"># We'd also like to get the exit status out of 'stop', so we'll combine the</span>
<span id="L16" class="LineNr"> 16 </span><span class="subxComment"># input target with an output status parameter into a type called 'exit-descriptor'.</span>
<span id="L17" class="LineNr"> 17 </span><span class="subxComment">#</span>
<span id="L18" class="LineNr"> 18 </span><span class="subxComment"># So the exit-descriptor looks like this:</span>
<span id="L19" class="LineNr"> 19 </span><span class="subxComment">#   target: address  # return address for 'stop' to unwind to</span>
<span id="L20" class="LineNr"> 20 </span><span class="subxComment">#   value: int  # exit status stop was called with</span>
<span id="L21" class="LineNr"> 21 </span><span class="subxComment">#</span>
<span id="L22" class="LineNr"> 22 </span><span class="subxComment"># 'stop' thus takes two parameters: an exit-descriptor and the exit status.</span>
<span id="L23" class="LineNr"> 23 </span><span class="subxComment">#</span>
<span id="L24" class="LineNr"> 24 </span><span class="subxComment"># 'stop' won't bother cleaning up any other processor state besides the stack,</span>
<span id="L25" class="LineNr"> 25 </span><span class="subxComment"># such as registers. Only esp will have a well-defined value after 'stop'</span>
<span id="L26" class="LineNr"> 26 </span><span class="subxComment"># returns. (This is a poor man's setjmp/longjmp, if you know what that is.)</span>
<span id="L27" class="LineNr"> 27 </span><span class="subxComment">#</span>
<span id="L28" class="LineNr"> 28 </span><span class="subxComment"># Before you can call any function that may call 'stop', you need to pass in an</span>
<span id="L29" class="LineNr"> 29 </span><span class="subxComment"># exit-descriptor to it. To create an exit-descriptor use 'tailor-exit-descriptor'</span>
<span id="L30" class="LineNr"> 30 </span><span class="subxComment"># below. It's not the most pleasant abstraction in the world.</span>
<span id="L31" class="LineNr"> 31 </span><span class="subxComment">#</span>
<span id="L32" class="LineNr"> 32 </span><span class="subxComment"># An exit-descriptor's target is its input, computed during 'tailor-exit-descriptor'.</span>
<span id="L33" class="LineNr"> 33 </span><span class="subxComment"># Its value is its output, computed during stop and available to the test.</span>
<span id="L34" class="LineNr"> 34 </span>
<span id="L35" class="LineNr"> 35 </span>== code
<span id="L36" class="LineNr"> 36 </span><span class="subxComment">#   instruction                     effective address                                                   register    displacement    immediate</span>
<span id="L37" class="LineNr"> 37 </span><span class="subxS1Comment"># . op          subop               mod             rm32          base        index         scale       r32</span>
<span id="L38" class="LineNr"> 38 </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="L39" class="LineNr"> 39 </span>
<span id="L40" class="LineNr"> 40 </span><span class="subxComment"># Configure an exit-descriptor for a call pushing 'nbytes' bytes of args to</span>
<span id="L41" class="LineNr"> 41 </span><span class="subxComment"># the stack.</span>
<span id="L42" class="LineNr"> 42 </span><span class="subxComment"># Ugly that we need to know the size of args. Don't allocate variables between</span>
<span id="L43" class="LineNr"> 43 </span><span class="subxComment"># tailor-exit-descriptor and the call it's for.</span>
<span id="L44" class="LineNr"> 44 </span><span class="subxFunction">tailor-exit-descriptor</span>:  <span class="subxComment"># ed: (addr exit-descriptor), nbytes: int</span>
<span id="L45" class="LineNr"> 45 </span>    <span class="subxS1Comment"># . prologue</span>
<span id="L46" class="LineNr"> 46 </span>    55/push-ebp
<span id="L47" class="LineNr"> 47 </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="L48" class="LineNr"> 48 </span>    <span class="subxS1Comment"># . save registers</span>
<span id="L49" class="LineNr"> 49 </span>    50/push-eax
<span id="L50" class="LineNr"> 50 </span>    51/push-ecx
<span id="L51" class="LineNr"> 51 </span>    <span class="subxComment"># eax = nbytes</span>
<span id="L52" class="LineNr"> 52 </span>    8b/copy                         1/mod/*+disp8   5/rm32/ebp   <span class="Normal"> . </span>         <span class="Normal"> . </span>           <span class="Normal"> . </span>          0/r32/eax   0xc/disp8      <span class="Normal"> . </span>                <span class="subxComment"># copy *(ebp+12) to eax</span>
<span id="L53" class="LineNr"> 53 </span>    <span class="subxComment"># Let X be the value of esp in the caller, before the call to tailor-exit-descriptor.</span>
<span id="L54" class="LineNr"> 54 </span>    <span class="subxComment"># The return address for a call in the caller's body will be at:</span>
<span id="L55" class="LineNr"> 55 </span>    <span class="subxComment">#   X-8 if the caller takes 4 bytes of args for the exit-descriptor (add 4 bytes for the return address)</span>
<span id="L56" class="LineNr"> 56 </span>    <span class="subxComment">#   X-12 if the caller takes 8 bytes of args</span>
<span id="L57" class="LineNr"> 57 </span>    <span class="subxComment">#   ..and so on</span>
<span id="L58" class="LineNr"> 58 </span>    <span class="subxComment"># That's the value we need to return: X-nbytes-4</span>
<span id="L59" class="LineNr"> 59 </span>    <span class="subxComment">#</span>
<span id="L60" class="LineNr"> 60 </span>    <span class="subxComment"># However, we also need to account for the perturbance to esp caused by the</span>
<span id="L61" class="LineNr"> 61 </span>    <span class="subxComment"># call to tailor-exit-descriptor. It pushes 8 bytes of args followed by 4</span>
<span id="L62" class="LineNr"> 62 </span>    <span class="subxComment"># bytes for the return address and 4 bytes to push ebp above.</span>
<span id="L63" class="LineNr"> 63 </span>    <span class="subxComment"># So ebp at this point is X-16.</span>
<span id="L64" class="LineNr"> 64 </span>    <span class="subxComment">#</span>
<span id="L65" class="LineNr"> 65 </span>    <span class="subxComment"># So the return address for the next call in the caller is:</span>
<span id="L66" class="LineNr"> 66 </span>    <span class="subxComment">#   ebp+8 if the caller takes 4 bytes of args</span>
<span id="L67" class="LineNr"> 67 </span>    <span class="subxComment">#   ebp+4 if the caller takes 8 bytes of args</span>
<span id="L68" class="LineNr"> 68 </span>    <span class="subxComment">#   ebp if the caller takes 12 bytes of args</span>
<span id="L69" class="LineNr"> 69 </span>    <span class="subxComment">#   ebp-4 if the caller takes 16 bytes of args</span>
<span id="L70" class="LineNr"> 70 </span>    <span class="subxComment">#   ..and so on</span>
<span id="L71" class="LineNr"> 71 </span>    <span class="subxComment"># That's ebp+12-nbytes.</span>
<span id="L72" class="LineNr"> 72 </span>    <span class="subxComment"># option 1: 6 + 3 bytes</span>
<span id="L73" class="LineNr"> 73 </span><span class="CommentedCode">#?     2d/subtract                     3/mod/direct    0/rm32/eax    .           .             .           .           .               8/imm32           # subtract from eax</span>
<span id="L74" class="LineNr"> 74 </span><span class="CommentedCode">#?     8d/copy-address                 0/mod/indirect  4/rm32/sib    5/base/ebp  0/index/eax   .           0/r32/eax   .               .                 # copy ebp+eax to eax</span>
<span id="L75" class="LineNr"> 75 </span>    <span class="subxComment"># option 2: 2 + 4 bytes</span>
<span id="L76" class="LineNr"> 76 </span>    f7          3/subop/negate      3/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>             <span class="Normal"> . </span>                <span class="subxComment"># negate eax</span>
<span id="L77" class="LineNr"> 77 </span>    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    5/base/ebp  0/index/eax  <span class="Normal"> . </span>          0/r32/eax   0xc/disp8        <span class="Normal"> . </span>              <span class="subxComment"># copy ebp+eax+12 to eax</span>
<span id="L78" class="LineNr"> 78 </span>    <span class="subxComment"># copy eax to ed-&gt;target</span>
<span id="L79" class="LineNr"> 79 </span>    8b/copy                         1/mod/*+disp8   5/rm32/ebp   <span class="Normal"> . </span>         <span class="Normal"> . </span>           <span class="Normal"> . </span>          1/r32/ecx   8/disp8        <span class="Normal"> . </span>                <span class="subxComment"># copy *(ebp+8) to ecx</span>
<span id="L80" class="LineNr"> 80 </span>    89/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 eax to *ecx</span>
<span id="L81" class="LineNr"> 81 </span>    <span class="subxComment"># initialize ed-&gt;value</span>
<span id="L82" class="LineNr"> 82 </span>    c7          0/subop/copy        1/mod/*+disp8   1/rm32/ecx   <span class="Normal"> . </span>         <span class="Normal"> . </span>           <span class="Normal"> . </span>         <span class="Normal"> . </span>          4/disp8         0/imm32           <span class="subxComment"># copy to *(ecx+4)</span>
<span id="L83" class="LineNr"> 83 </span><span class="Constant">$tailor-exit-descriptor:end</span>:
<span id="L84" class="LineNr"> 84 </span>    <span class="subxS1Comment"># . restore registers</span>
<span id="L85" class="LineNr"> 85 </span>    59/pop-to-ecx
<span id="L86" class="LineNr"> 86 </span>    58/pop-to-eax
<span id="L87" class="LineNr"> 87 </span>    <span class="subxS1Comment"># . epilogue</span>
<span id="L88" class="LineNr"> 88 </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="L89" class="LineNr"> 89 </span>    5d/pop-to-ebp
<span id="L90" class="LineNr"> 90 </span>    c3/return
<span id="L91" class="LineNr"> 91 </span>
<span id="L92" class="LineNr"> 92 </span><span class="subxFunction">stop</span>:  <span class="subxComment"># ed: (addr exit-descriptor), value: int</span>
<span id="L93" class="LineNr"> 93 </span>    <span class="subxComment"># no prologue; one way or another, we're going to clobber registers</span>
<span id="L94" class="LineNr"> 94 </span>    <span class="subxComment"># eax = ed</span>
<span id="L95" class="LineNr"> 95 </span>    8b/copy                         1/mod/*+disp8   4/rm32/sib    4/base/esp  4/index/none <span class="Normal"> . </span>          0/r32/eax   4/disp8        <span class="Normal"> . </span>                <span class="subxComment"># copy *(esp+4) to eax</span>
<span id="L96" class="LineNr"> 96 </span>    <span class="subxComment"># if (ed == 0) really exit</span>
<span id="L97" class="LineNr"> 97 </span>    3d/compare-eax-and 0/imm32
<span id="L98" class="LineNr"> 98 </span>    74/jump-if-=  $stop:real/disp8
<span id="L99" class="LineNr"> 99 </span>    <span class="subxComment"># if (ed-&gt;target == 0) really exit</span>
<span id="L100" class="LineNr">100 </span>    81          7/subop/compare     0/mod/indirect  0/rm32/eax   <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 *eax</span>
<span id="L101" class="LineNr">101 </span>    74/jump-if-=  $stop:real/disp8
<span id="L102" class="LineNr">102 </span><span class="Constant">$stop:fake</span>:
<span id="L103" class="LineNr">103 </span>    <span class="subxComment"># ed-&gt;value = value+1</span>
<span id="L104" class="LineNr">104 </span>    8b/copy                         1/mod/*+disp8   4/rm32/sib    4/base/esp  4/index/none <span class="Normal"> . </span>          1/r32/ecx   8/disp8        <span class="Normal"> . </span>                <span class="subxComment"># copy *(esp+8) to ecx</span>
<span id="L105" class="LineNr">105 </span>    41/increment-ecx
<span id="L106" class="LineNr">106 </span>    89/copy                         1/mod/*+disp8   0/rm32/eax   <span class="Normal"> . </span>         <span class="Normal"> . </span>           <span class="Normal"> . </span>          1/r32/ecx   4/disp8        <span class="Normal"> . </span>                <span class="subxComment"># copy ecx to *(eax+4)</span>
<span id="L107" class="LineNr">107 </span>    <span class="subxComment"># perform a non-local jump to ed-&gt;target</span>
<span id="L108" class="LineNr">108 </span>    8b/copy                         0/mod/indirect  0/rm32/eax   <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 *eax to esp</span>
<span id="L109" class="LineNr">109 </span><span class="Constant">$stop:end1</span>:
<span id="L110" class="LineNr">110 </span>    <span class="subxComment"># never gets here</span>
<span id="L111" class="LineNr">111 </span>    c3/return  <span class="subxComment"># doesn't return to caller</span>
<span id="L112" class="LineNr">112 </span><span class="Constant">$stop:real</span>:
<span id="L113" class="LineNr">113 </span>    <span class="subxS1Comment"># . syscall(exit, value)</span>
<span id="L114" class="LineNr">114 </span>    8b/copy                         1/mod/*+disp8   4/rm32/sib    4/base/esp  4/index/none <span class="Normal"> . </span>          3/r32/ebx   8/disp8        <span class="Normal"> . </span>                <span class="subxComment"># copy *(esp+8) to ebx</span>
<span id="L115" class="LineNr">115 </span>    e8/call  syscall_exit/disp32
<span id="L116" class="LineNr">116 </span><span class="Constant">$stop:end2</span>:
<span id="L117" class="LineNr">117 </span>    <span class="subxComment"># never gets here</span>
<span id="L118" class="LineNr">118 </span>    c3/return  <span class="subxComment"># doesn't return to caller</span>
<span id="L119" class="LineNr">119 </span>
<span id="L120" class="LineNr">120 </span><span class="subxTest">test-stop-skips-returns-on-exit</span>:
<span id="L121" class="LineNr">121 </span>    <span class="subxComment"># This looks like the standard prologue, but is here for different reasons.</span>
<span id="L122" class="LineNr">122 </span>    <span class="subxComment"># A function calling 'stop' can't rely on ebp persisting past the call.</span>
<span id="L123" class="LineNr">123 </span>    <span class="subxComment">#</span>
<span id="L124" class="LineNr">124 </span>    <span class="subxComment"># Use ebp here as a stable base to refer to locals and arguments from in the</span>
<span id="L125" class="LineNr">125 </span>    <span class="subxComment"># presence of push/pop/call instructions.</span>
<span id="L126" class="LineNr">126 </span>    <span class="subxComment"># *Don't* use ebp as a way to restore esp.</span>
<span id="L127" class="LineNr">127 </span>    55/push-ebp
<span id="L128" class="LineNr">128 </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="L129" class="LineNr">129 </span>    <span class="subxComment"># Make room for an exit descriptor on the stack. That's almost always the</span>
<span id="L130" class="LineNr">130 </span>    <span class="subxComment"># right place for it, available only as long as it's legal to use. Once this</span>
<span id="L131" class="LineNr">131 </span>    <span class="subxComment"># containing function returns we'll need a new exit descriptor.</span>
<span id="L132" class="LineNr">132 </span>    <span class="subxComment"># var ed/eax: exit-descriptor</span>
<span id="L133" class="LineNr">133 </span>    68/push  0/imm32
<span id="L134" class="LineNr">134 </span>    68/push  0/imm32
<span id="L135" class="LineNr">135 </span>    89/copy                         3/mod/direct    0/rm32/eax   <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 eax</span>
<span id="L136" class="LineNr">136 </span>    <span class="subxComment"># Size the exit-descriptor precisely for the next call below, to _test-stop-1.</span>
<span id="L137" class="LineNr">137 </span>    <span class="subxComment"># tailor-exit-descriptor(ed, 4)</span>
<span id="L138" class="LineNr">138 </span>    <span class="subxS2Comment"># . . push args</span>
<span id="L139" class="LineNr">139 </span>    68/push  4/imm32/nbytes-of-args-for-_test-stop-1
<span id="L140" class="LineNr">140 </span>    50/push-eax
<span id="L141" class="LineNr">141 </span>    <span class="subxS2Comment"># . . call</span>
<span id="L142" class="LineNr">142 </span>    e8/call  <a href='110stop.subx.html#L44'>tailor-exit-descriptor</a>/disp32
<span id="L143" class="LineNr">143 </span>    <span class="subxS2Comment"># . . discard args</span>
<span id="L144" class="LineNr">144 </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="L145" class="LineNr">145 </span>    <span class="subxS1Comment"># . _test-stop-1(ed)</span>
<span id="L146" class="LineNr">146 </span>    <span class="subxS2Comment"># . . push args</span>
<span id="L147" class="LineNr">147 </span>    50/push-eax
<span id="L148" class="LineNr">148 </span>    <span class="subxS2Comment"># . . call</span>
<span id="L149" class="LineNr">149 </span>    e8/call  <a href='110stop.subx.html#L170'>_test-stop-1</a>/disp32
<span id="L150" class="LineNr">150 </span>    <span class="subxComment"># registers except esp may be clobbered at this point</span>
<span id="L151" class="LineNr">151 </span>    <span class="subxComment"># restore args</span>
<span id="L152" class="LineNr">152 </span>    58/pop-to-eax
<span id="L153" class="LineNr">153 </span>    <span class="subxComment"># check that _test-stop-1 tried to call exit(1)</span>
<span id="L154" class="LineNr">154 </span>    <span class="subxS1Comment"># . check-ints-equal(ed-&gt;value, 2, msg)  # i.e. stop was called with value 1</span>
<span id="L155" class="LineNr">155 </span>    <span class="subxS2Comment"># . . push args</span>
<span id="L156" class="LineNr">156 </span>    68/push  <span class="Constant">&quot;F - test-stop-skips-returns-on-exit&quot;</span>/imm32
<span id="L157" class="LineNr">157 </span>    68/push  2/imm32
<span id="L158" class="LineNr">158 </span>    <span class="subxS2Comment"># . . push ed-&gt;value</span>
<span id="L159" class="LineNr">159 </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>          4/disp8        <span class="Normal"> . </span>                <span class="subxComment"># push *(eax+4)</span>
<span id="L160" class="LineNr">160 </span>    <span class="subxS2Comment"># . . call</span>
<span id="L161" class="LineNr">161 </span>    e8/call  <a href='102test.subx.html#L23'>check-ints-equal</a>/disp32
<span id="L162" class="LineNr">162 </span>    <span class="subxS2Comment"># . . discard args</span>
<span id="L163" class="LineNr">163 </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="L164" class="LineNr">164 </span>    <span class="subxS1Comment"># . epilogue</span>
<span id="L165" class="LineNr">165 </span>    <span class="subxComment"># don't restore esp from ebp; manually reclaim locals</span>
<span id="L166" class="LineNr">166 </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="L167" class="LineNr">167 </span>    5d/pop-to-ebp
<span id="L168" class="LineNr">168 </span>    c3/return
<span id="L169" class="LineNr">169 </span>
<span id="L170" class="LineNr">170 </span><span class="subxMinorFunction">_test-stop-1</span>:  <span class="subxComment"># ed: (addr exit-descriptor)</span>
<span id="L171" class="LineNr">171 </span>    <span class="subxS1Comment"># . prologue</span>
<span id="L172" class="LineNr">172 </span>    55/push-ebp
<span id="L173" class="LineNr">173 </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="L174" class="LineNr">174 </span>    <span class="subxComment"># _test-stop-2(ed)</span>
<span id="L175" class="LineNr">175 </span>    <span class="subxS2Comment"># . . push args</span>
<span id="L176" class="LineNr">176 </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="L177" class="LineNr">177 </span>    <span class="subxS2Comment"># . . call</span>
<span id="L178" class="LineNr">178 </span>    e8/call  <a href='110stop.subx.html#L197'>_test-stop-2</a>/disp32
<span id="L179" class="LineNr">179 </span>    <span class="subxComment"># should never get past this point</span>
<span id="L180" class="LineNr">180 </span><span class="Constant">$_test-stop-1:dead-end</span>:
<span id="L181" class="LineNr">181 </span>    <span class="subxS2Comment"># . . discard args</span>
<span id="L182" class="LineNr">182 </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="L183" class="LineNr">183 </span>    <span class="subxComment"># signal test failed: check-ints-equal(1, 0, msg)</span>
<span id="L184" class="LineNr">184 </span>    <span class="subxS2Comment"># . . push args</span>
<span id="L185" class="LineNr">185 </span>    68/push  <span class="Constant">&quot;F - test-stop-skips-returns-on-exit&quot;</span>/imm32
<span id="L186" class="LineNr">186 </span>    68/push  0/imm32
<span id="L187" class="LineNr">187 </span>    68/push  1/imm32
<span id="L188" class="LineNr">188 </span>    <span class="subxS2Comment"># . . call</span>
<span id="L189" class="LineNr">189 </span>    e8/call  <a href='102test.subx.html#L23'>check-ints-equal</a>/disp32
<span id="L190" class="LineNr">190 </span>    <span class="subxS2Comment"># . . discard args</span>
<span id="L191" class="LineNr">191 </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="L192" class="LineNr">192 </span>    <span class="subxS1Comment"># . epilogue</span>
<span id="L193" class="LineNr">193 </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="L194" class="LineNr">194 </span>    5d/pop-to-ebp
<span id="L195" class="LineNr">195 </span>    c3/return
<span id="L196" class="LineNr">196 </span>
<span id="L197" class="LineNr">197 </span><span class="subxMinorFunction">_test-stop-2</span>:  <span class="subxComment"># ed: (addr exit-descriptor)</span>
<span id="L198" class="LineNr">198 </span>    <span class="subxS1Comment"># . prologue</span>
<span id="L199" class="LineNr">199 </span>    55/push-ebp
<span id="L200" class="LineNr">200 </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="L201" class="LineNr">201 </span>    <span class="subxS1Comment"># . stop(ed, 1)</span>
<span id="L202" class="LineNr">202 </span>    <span class="subxS2Comment"># . . push args</span>
<span id="L203" class="LineNr">203 </span>    68/push  1/imm32
<span id="L204" class="LineNr">204 </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="L205" class="LineNr">205 </span>    <span class="subxS2Comment"># . . call</span>
<span id="L206" class="LineNr">206 </span>    e8/call  <a href='110stop.subx.html#L92'>stop</a>/disp32
<span id="L207" class="LineNr">207 </span>    <span class="subxComment"># should never get past this point</span>
<span id="L208" class="LineNr">208 </span><span class="Constant">$_test-stop-2:dead-end</span>:
<span id="L209" class="LineNr">209 </span>    <span class="subxS1Comment"># . epilogue</span>
<span id="L210" class="LineNr">210 </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="L211" class="LineNr">211 </span>    5d/pop-to-ebp
<span id="L212" class="LineNr">212 </span>    c3/return
<span id="L213" class="LineNr">213 </span>
<span id="L214" class="LineNr">214 </span><span class="subxS2Comment"># . . vim&#0058;nowrap:textwidth=0</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->