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8    <title>m4x4 - 4x4 multiply</title>
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10  <body>
11    <h1>m4x4 - 4x4 multiply</h1>
12
13    <h2>Calling Format</h2>
14    <div class="section">
15      <pre class="definition">
16m4x4    dest, src0, src1
17</pre>
18    </div>
19
20    <h2>Operands</h2>
21    <div class="section">
22      <table class="arguments">
23        <thead>
24          <tr>
25            <th>Name</th>
26            <td>Registers</td>
27          </tr>
28        </thead>
29        <tr>
30          <th>dest</th>
31          <td>
32            An output register or temporary register.<br>Cannot use anything other than the default mask  { .xyzw }.<br>
33          </td>
34        </tr>
35        <tr>
36          <th>src0</th>
37          <td>
38            A temporary register, an input register, or a floating-point constant register.<br>
39          </td>
40        </tr>
41        <tr>
42          <th>src1</th>
43          <td>
44            A temporary register, an input register, or a floating-point constant register.<br>Specifies the starting register of a 4x4  matrix. (In other words, if <SPAN class="argument">src1</SPAN> is <CODE>r0</CODE>, then the 4x4 matrix is stored in <CODE>r0</CODE>, <CODE>r1</CODE>, <CODE>r2</CODE> and <CODE>r3</CODE>.)<br>
45          </td>
46        </tr>
47      </table>
48      <p class="notice">
49        You cannot specify a floating-point constant register for both <SPAN class="argument">src0</SPAN> and <SPAN class="argument">src1</SPAN>.<br> You cannot specify an input register for both <SPAN class="argument">src0</SPAN> and <SPAN class="argument">src1</SPAN> at the same time.<br> You cannot specify the same register for <SPAN class="argument">dest</SPAN> and <SPAN class="argument">src0</SPAN>.<br>
50      </p>
51      <p class="warning">
52        If you set <SPAN class="argument">dest</SPAN> to the registers that immediately follow <SPAN class="argument">src1</SPAN> (this is <SPAN class="argument">src2</SPAN>, <SPAN class="argument">src3</SPAN>, <SPAN class="argument">src4</SPAN> in Macro Expansion below), there is no way to anticipate the result because the contents of those registers will be updated during the execution of the expanded instructions.<br>
53      </p>
54    </div>
55
56    <h2>Overview</h2>
57    <div class="section">
58      <p>
59        Stores the result of multiplying a 4x4 matrix and a 4-component vector in <SPAN class="argument">dest</SPAN>.<br>
60      </p>
61    </div>
62
63    <h2>Operation</h2>
64    <div class="section">
65<pre class="definition">
66src2 = Next_Index_Of ( src1 )
67src3 = Next_Index_Of ( src2 )
68src4 = Next_Index_Of ( src3 )
69dest.x = ( src0.x * src1.x ) + ( src0.y * src1.y ) + ( src0.z * src1.z ) + ( src0.w * src1.w )
70dest.y = ( src0.x * src2.x ) + ( src0.y * src2.y ) + ( src0.z * src2.z ) + ( src0.w * src2.w )
71dest.z = ( src0.x * src3.x ) + ( src0.y * src3.y ) + ( src0.z * src3.z ) + ( src0.w * src3.w )
72dest.w = ( src0.x * src4.x ) + ( src0.y * src4.y ) + ( src0.z * src4.z ) + ( src0.w * src4.w )
73</pre>
74    </div>
75
76    <h2>Macro Expansion</h2>
77    <div class="section">
78<pre class="definition">
79dp4     dest.x, src0, src1
80dp4     dest.y, src0, src2  // src2 = next index of src1
81dp4     dest.z, src0, src3  // src3 = next index of src2
82dp4     dest.w, src0, src4  // src4 = next index of src3
83</pre>
84    </div>
85
86    <h2>Code Example</h2>
87    <div class="section">
88<pre class="definition">
89m4x4    r0, r1, c0
90// This is expanded as follows
91// dp4     r0.x, r1, c0
92// dp4     r0.y, r1, c1
93// dp4     r0.z, r1, c2
94// dp4     r0.w, r1, c3
95</pre>
96    </div>
97
98    <h2>Timetable</h2>
99    <div class="section">
100      <table class="timetable">
101        <tr>
102          <th></th>
103          <th>1</th><th>2</th><th>3</th><th>4</th><th>5</th><th>6</th><th>7</th><th>8</th><th>9</th>
104        </tr>
105        <tr>
106          <th>dp4</th>
107          <td class="read">read</td>
108          <td class="MUL">MUL</td>
109          <td class="ADD">ADD</td>
110          <td class="ADD">ADD</td>
111          <td class="post">post</td>
112          <td class="write">write</td>
113        </tr>
114        <tr>
115          <th>dp4</th>
116          <td class="empty"></td>
117          <td class="read">read</td>
118          <td class="MUL">MUL</td>
119          <td class="ADD">ADD</td>
120          <td class="ADD">ADD</td>
121          <td class="post">post</td>
122          <td class="write">write</td>
123        </tr>
124        <tr>
125          <th>dp4</th>
126          <td class="empty" colspan="2"></td>
127          <td class="read">read</td>
128          <td class="MUL">MUL</td>
129          <td class="ADD">ADD</td>
130          <td class="ADD">ADD</td>
131          <td class="post">post</td>
132          <td class="write">write</td>
133        </tr>
134        <tr>
135          <th>dp4</th>
136          <td class="empty" colspan="3"></td>
137          <td class="read">read</td>
138          <td class="MUL">MUL</td>
139          <td class="ADD">ADD</td>
140          <td class="ADD">ADD</td>
141          <td class="post">post</td>
142          <td class="write">write</td>
143          <td class="dummy"></td>
144        </tr>
145      </table>
146    </div>
147
148
149  <h2>Revision History</h2>
150  <div class="section">
151    <dl class="history">
152      <dt>2011/12/20</dt>
153      <dd>Initial version.<br />
154      </dd>
155    </dl>
156  </div>
157
158  <hr><p>CONFIDENTIAL</p></body>
159</html>