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<title>if-test</title>
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<h1>if-test</h1>
<h2>Purpose</h2>
<p>
Branch to the given destination if the given two registers' values compare as
specified.
</p>
<p>
Note: The branch offset may not be 0. (A spin loop may be legally constructed
either by branching around a backward goto or by including a nop as a target
before the branch.)
</p>
<h2>Details</h2>
<table class="instruc">
<thead>
<tr>
<th>Op & Format</th>
<th>Mnemonic / Syntax</th>
<th>Arguments</th>
</tr>
</thead>
<tbody>
<tr>
<td>32..37 22t</td>
<td>if-<i>test</i> vA, vB, +CCCC<br/>
32: if-eq<br/>
33: if-ne<br/>
34: if-lt<br/>
35: if-ge<br/>
36: if-gt<br/>
37: if-le<br/>
</td>
<td><code>A:</code> first register to test (4 bits)<br/>
<code>B:</code> second register to test (4 bits)<br/>
<code>C:</code> signed branch offset (16 bits)</td>
</tr>
</tbody>
</table>
<h2>Constraints</h2>
<ul>
<li>
A and B must be valid register indices for the current stack frame.
</li>
<li>
Registers vA and vB must not contain a reference value.
</li>
<li>
Registers vA and vB must not be part of a register pair.
</li>
<li>
Registers vA and vB must not contain a floating point value (???).
</li>
C must of a signed offset that, when added to the PC of the instruction,
points to a valid bytecode instruction inside the same method.
</li>
</ul>
<h2>Behavior</h2>
<ul>
<li>
The values of registers vA and vB are compared according to the <test>
condition. Two results are possible:
<ul>
<li>
The condition holds. The value of C is used as a signed offset to the
address of the if-<test> instruction. Execution continues at the
resulting address.
</li>
<li>
The condition does not hold. Execution continues at the instruction
following the if-<test> instruction.
</li>
</ul>
</li>
</ul>
<h2>Exceptions</h2>
<p>
None.
</p>
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