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      6 <title>if-test</title>
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     10 <body>
     11 
     12 <h1>if-test</h1>
     13 
     14 <h2>Purpose</h2>
     15 
     16 <p>
     17 Branch to the given destination if the given two registers' values compare as
     18 specified.
     19 </p>
     20 <p>
     21 Note: The branch offset may not be 0. (A spin loop may be legally constructed
     22 either by branching around a backward goto or by including a nop as a target
     23 before the branch.) 
     24 </p>
     25 
     26 <h2>Details</h2>
     27 
     28 <table class="instruc">
     29 <thead>
     30 <tr>
     31   <th>Op &amp; Format</th>
     32   <th>Mnemonic / Syntax</th>
     33   <th>Arguments</th>
     34 </tr>
     35 </thead>
     36 <tbody>
     37 <tr>
     38   <td>32..37 22t</td>
     39   <td>if-<i>test</i> vA, vB, +CCCC<br/>
     40     32: if-eq<br/>
     41     33: if-ne<br/>
     42     34: if-lt<br/>
     43     35: if-ge<br/>
     44     36: if-gt<br/>
     45     37: if-le<br/>
     46   </td>
     47   <td><code>A:</code> first register to test (4 bits)<br/>
     48     <code>B:</code> second register to test (4 bits)<br/>
     49     <code>C:</code> signed branch offset (16 bits)</td>
     50 </tr>
     51 </tbody>
     52 </table>
     53 
     54 <h2>Constraints</h2>
     55 
     56 <ul>
     57   <li>
     58     A and B must be valid register indices for the current stack frame.
     59   </li>
     60   <li>
     61     Registers vA and vB must not contain a reference value.
     62   </li>
     63   <li>
     64     Registers vA and vB must not be part of a register pair.
     65   </li>
     66   <li>
     67     Registers vA and vB must not contain a floating point value (???).
     68   </li>
     69     C must of a signed offset that, when added to the PC of the instruction,
     70     points to a valid bytecode instruction inside the same method.
     71   </li> 
     72 </ul>
     73 
     74 <h2>Behavior</h2>
     75 
     76 <ul>
     77   <li>
     78     The values of registers vA and vB are compared according to the &lt;test&gt;
     79     condition. Two results are possible:
     80     <ul>
     81       <li>
     82         The condition holds. The value of C is used as a signed offset to the
     83         address of the if-&lt;test&gt; instruction. Execution continues at the
     84         resulting address.
     85       </li>
     86       <li>
     87         The condition does not hold. Execution continues at the instruction
     88         following the if-&lt;test&gt; instruction.
     89       </li>
     90     </ul>
     91   </li>
     92 </ul> 
     93 
     94 <h2>Exceptions</h2>
     95 
     96 <p>
     97 None.
     98 </p>
     99 
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