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1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
2
3<html>
4
5<head>
6<title>move-wide</title>
7<link rel=stylesheet href="opcode.css">
8</head>
9
10<body>
11
12<h1>move-wide</h1>
13
14<h2>Purpose</h2>
15
16<p>
17Move the contents of one register-pair to another.
18</p>
19<p>
20Note: It is legal to move from vN to either vN-1 or vN+1, so implementations
21must arrange for both halves of a register pair to be read before anything is
22written.
23</p>
24
25<h2>Details</h2>
26
27<table class="instruc">
28<thead>
29<tr>
30  <th>Op &amp; Format</th>
31  <th>Mnemonic / Syntax</th>
32  <th>Arguments</th>
33</tr>
34</thead>
35<tbody>
36<tr>
37  <td>04 12x</td>
38  <td>move-wide vA, vB</td>
39  <td><code>A:</code> destination register pair (4 bits)<br/>
40    <code>B:</code> source register pair (4 bits)</td>
41</tr>
42<tr>
43  <td>05 22x</td>
44  <td>move-wide/from16 vAA, vBBBB</td>
45  <td><code>A:</code> destination register pair (8 bits)<br/>
46    <code>B:</code> source register pair (16 bits)</td>
47</tr>
48<tr>
49  <td>06 32x</td>
50  <td>move-wide/16 vAAAA, vBBBB</td>
51  <td><code>A:</code> destination register pair (16 bits)<br/>
52    <code>B:</code> source register pair (16 bits)</td>
53</tr>
54</tbody>
55</table>
56
57<h2>Constraints</h2>
58
59<ul>
60  <li>
61    Both A+1 and B+1 must be valid register indices in the current stackframe
62    (which includes A and B being valid).
63  </li>
64  <li>
65    Register vB must be the lower half of a register pair (which excludes the
66    case of it containing a reference).
67  </li>
68  <li>
69    Both register vB and v(B+1) must be defined.
70  </li>
71</ul>
72
73<h2>Behavior</h2>
74
75<ul>
76  <li>
77    The value of register vB is moved to register vA, that is, vA' = vB.
78  </li>
79  <li>
80    The value of register v(B+1) is moved to register v(A+1), that is, v(A+1)'
81    = v(B+1).
82  </li>
83  <li>
84    If register v(A-1) is the lower half of a register pair, then v(A-1)'
85    becomes undefined.
86  </li>
87  <li>
88    If register v(A+2) is the upper half of a register pair, then v(A+2)'
89    becomes undefined.
90  </li>
91  <li>
92    If A = B-1, then v(B+1)' becomes undefined.
93  </li>
94  <li>
95    If A = B+1, then v(B)' becomes undefined.
96  </li>
97</ul>
98
99<h2>Exceptions</h2>
100
101<p>
102None.
103</p>
104
105</body>
106</html>
107