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
|
<!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 - subx/011direct_addressing.cc</title>
<meta name="Generator" content="Vim/7.4">
<meta name="plugin-version" content="vim7.4_v2">
<meta name="syntax" content="cpp">
<meta name="settings" content="number_lines,use_css,pre_wrap,no_foldcolumn,expand_tabs,line_ids,prevent_copy=">
<meta name="colorscheme" content="minimal">
<style type="text/css">
<!--
pre { white-space: pre-wrap; font-family: monospace; color: #aaaaaa; background-color: #080808; }
body { font-size: 12pt; font-family: monospace; color: #aaaaaa; background-color: #080808; }
a { color:#eeeeee; text-decoration: none; }
a:hover { text-decoration: underline; }
* { font-size: 12pt; font-size: 1em; }
.Constant { color: #00a0a0; }
.Special { color: #c00000; }
.Conceal { color: #4e4e4e; }
.SalientComment { color: #00ffff; }
.Comment { color: #9090ff; }
.Comment a { color:#0000ee; text-decoration:underline; }
.Delimiter { color: #800080; }
.LineNr { color: #444444; }
.Identifier { color: #c0a020; }
.Normal { color: #aaaaaa; background-color: #080808; padding-bottom: 1px; }
.PreProc { color: #800080; }
.cSpecial { color: #008000; }
.traceContains { color: #008000; }
-->
</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;
}
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();'>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr"> 1 </span><span class="Comment">//: operating directly on a register</span>
<span id="L2" class="LineNr"> 2 </span>
<span id="L3" class="LineNr"> 3 </span><span class="Delimiter">:(scenario add_r32_to_r32)</span>
<span id="L4" class="LineNr"> 4 </span><span class="Special">% Reg[0].i = 0x10;</span>
<span id="L5" class="LineNr"> 5 </span><span class="Special">% Reg[3].i = 1;</span>
<span id="L6" class="LineNr"> 6 </span><span class="Comment"># op ModR/M SIB displacement immediate</span>
<span id="L7" class="LineNr"> 7 </span> <span class="PreProc">0</span><span class="Constant">1</span> d8 <span class="Comment"># add EBX (reg 3) to EAX (reg 0)</span>
<span id="L8" class="LineNr"> 8 </span><span class="traceContains">+run: add reg 3 to effective address</span>
<span id="L9" class="LineNr"> 9 </span><span class="traceContains">+run: effective address is reg 0</span>
<span id="L10" class="LineNr">10 </span><span class="traceContains">+run: storing 0x00000011</span>
<span id="L11" class="LineNr">11 </span>
<span id="L12" class="LineNr">12 </span><span class="Delimiter">:(before "End Single-Byte Opcodes")</span>
<span id="L13" class="LineNr">13 </span><span class="Normal">case</span> <span class="Constant">0x01</span>: <span class="Delimiter">{</span> <span class="Comment">// add r32 to r/m32</span>
<span id="L14" class="LineNr">14 </span> <span class="Normal">uint8_t</span> modrm = next<span class="Delimiter">();</span>
<span id="L15" class="LineNr">15 </span> <span class="Normal">uint8_t</span> arg2 = <span class="Delimiter">(</span>modrm>><span class="Constant">3</span><span class="Delimiter">)</span>&<span class="Constant">0x7</span><span class="Delimiter">;</span>
<span id="L16" class="LineNr">16 </span> trace<span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">"add reg "</span> << NUM<span class="Delimiter">(</span>arg2<span class="Delimiter">)</span> << <span class="Constant">" to effective address"</span> << end<span class="Delimiter">();</span>
<span id="L17" class="LineNr">17 </span> <span class="Normal">int32_t</span>* arg1 = effective_address<span class="Delimiter">(</span>modrm<span class="Delimiter">);</span>
<span id="L18" class="LineNr">18 </span> BINARY_ARITHMETIC_OP<span class="Delimiter">(</span>+<span class="Delimiter">,</span> *arg1<span class="Delimiter">,</span> Reg[arg2]<span class="Delimiter">.</span>i<span class="Delimiter">);</span>
<span id="L19" class="LineNr">19 </span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L20" class="LineNr">20 </span><span class="Delimiter">}</span>
<span id="L21" class="LineNr">21 </span>
<span id="L22" class="LineNr">22 </span><span class="Delimiter">:(code)</span>
<span id="L23" class="LineNr">23 </span><span class="Comment">// Implement tables 2-2 and 2-3 in the Intel manual, Volume 2.</span>
<span id="L24" class="LineNr">24 </span><span class="Comment">// We return a pointer so that instructions can write to multiple bytes in</span>
<span id="L25" class="LineNr">25 </span><span class="Comment">// 'Mem' at once.</span>
<span id="L26" class="LineNr">26 </span><span class="Normal">int32_t</span>* effective_address<span class="Delimiter">(</span><span class="Normal">uint8_t</span> modrm<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L27" class="LineNr">27 </span> <span class="Normal">uint8_t</span> mod = <span class="Delimiter">(</span>modrm>><span class="Constant">6</span><span class="Delimiter">);</span>
<span id="L28" class="LineNr">28 </span> <span class="Comment">// ignore middle 3 'reg opcode' bits</span>
<span id="L29" class="LineNr">29 </span> <span class="Normal">uint8_t</span> rm = modrm & <span class="Constant">0x7</span><span class="Delimiter">;</span>
<span id="L30" class="LineNr">30 </span> <span class="Normal">int32_t</span>* result = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L31" class="LineNr">31 </span> <span class="Normal">switch</span> <span class="Delimiter">(</span>mod<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L32" class="LineNr">32 </span> <span class="Normal">case</span> <span class="Constant">3</span>:
<span id="L33" class="LineNr">33 </span> <span class="Conceal">¦</span> <span class="Comment">// mod 3 is just register direct addressing</span>
<span id="L34" class="LineNr">34 </span> <span class="Conceal">¦</span> trace<span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">"effective address is reg "</span> << NUM<span class="Delimiter">(</span>rm<span class="Delimiter">)</span> << end<span class="Delimiter">();</span>
<span id="L35" class="LineNr">35 </span> <span class="Conceal">¦</span> result = &Reg[rm]<span class="Delimiter">.</span>i<span class="Delimiter">;</span>
<span id="L36" class="LineNr">36 </span> <span class="Conceal">¦</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L37" class="LineNr">37 </span> <span class="Comment">// End Mod Special-cases</span>
<span id="L38" class="LineNr">38 </span> <span class="Normal">default</span>:
<span id="L39" class="LineNr">39 </span> <span class="Conceal">¦</span> cerr << <span class="Constant">"unrecognized mod bits: "</span> << NUM<span class="Delimiter">(</span>mod<span class="Delimiter">)</span> << <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
<span id="L40" class="LineNr">40 </span> <span class="Conceal">¦</span> exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L41" class="LineNr">41 </span> <span class="Delimiter">}</span>
<span id="L42" class="LineNr">42 </span> <span class="Identifier">return</span> result<span class="Delimiter">;</span>
<span id="L43" class="LineNr">43 </span><span class="Delimiter">}</span>
<span id="L44" class="LineNr">44 </span>
<span id="L45" class="LineNr">45 </span><span class="SalientComment">//:: subtract</span>
<span id="L46" class="LineNr">46 </span>
<span id="L47" class="LineNr">47 </span><span class="Delimiter">:(scenario subtract_r32_from_r32)</span>
<span id="L48" class="LineNr">48 </span><span class="Special">% Reg[0].i = 10;</span>
<span id="L49" class="LineNr">49 </span><span class="Special">% Reg[3].i = 1;</span>
<span id="L50" class="LineNr">50 </span><span class="Comment"># op ModR/M SIB displacement immediate</span>
<span id="L51" class="LineNr">51 </span> <span class="Constant">29</span> d8 <span class="Comment"># subtract EBX (reg 3) from EAX (reg 0)</span>
<span id="L52" class="LineNr">52 </span><span class="traceContains">+run: subtract reg 3 from effective address</span>
<span id="L53" class="LineNr">53 </span><span class="traceContains">+run: effective address is reg 0</span>
<span id="L54" class="LineNr">54 </span><span class="traceContains">+run: storing 0x00000009</span>
<span id="L55" class="LineNr">55 </span>
<span id="L56" class="LineNr">56 </span><span class="Delimiter">:(before "End Single-Byte Opcodes")</span>
<span id="L57" class="LineNr">57 </span><span class="Normal">case</span> <span class="Constant">0x29</span>: <span class="Delimiter">{</span> <span class="Comment">// subtract r32 from r/m32</span>
<span id="L58" class="LineNr">58 </span> <span class="Normal">uint8_t</span> modrm = next<span class="Delimiter">();</span>
<span id="L59" class="LineNr">59 </span> <span class="Normal">uint8_t</span> arg2 = <span class="Delimiter">(</span>modrm>><span class="Constant">3</span><span class="Delimiter">)</span>&<span class="Constant">0x7</span><span class="Delimiter">;</span>
<span id="L60" class="LineNr">60 </span> trace<span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">"subtract reg "</span> << NUM<span class="Delimiter">(</span>arg2<span class="Delimiter">)</span> << <span class="Constant">" from effective address"</span> << end<span class="Delimiter">();</span>
<span id="L61" class="LineNr">61 </span> <span class="Normal">int32_t</span>* arg1 = effective_address<span class="Delimiter">(</span>modrm<span class="Delimiter">);</span>
<span id="L62" class="LineNr">62 </span> BINARY_ARITHMETIC_OP<span class="Delimiter">(</span>-<span class="Delimiter">,</span> *arg1<span class="Delimiter">,</span> Reg[arg2]<span class="Delimiter">.</span>i<span class="Delimiter">);</span>
<span id="L63" class="LineNr">63 </span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L64" class="LineNr">64 </span><span class="Delimiter">}</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->
|