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<p>Below is some Java code, with a comment, from ZXing's ReedSolomon
error correction. It points out a hotspot bug with a workaround.
What would be the Squeak code to calculate the denominator? I'm
guessing that this hotspot bug does not exist in Squeak. I tried
this code and it fails:</p>
<blockquote>
<p>denominator = field <br/>
multiply: denominator <br/>
by: (field <br/>
addOrSubtract: 1<br/>
by: (field <br/>
multiply: (errorLocations at: j) <br/>
by: xiInverse)).</p>
</blockquote>
<p>Notice the commented out code in the first 2 lines of the java
comment. The computation seems to revolve around</p>
<blockquote>
<p><b>field addOrSubtract: 1 by: term</b><br/>
</p>
</blockquote>
<p>or <br/>
</p>
<blockquote>
<p><b>(term & 0x1) == 0 ? term | 1 : term & ~1;</b></p>
</blockquote>
<p>Here is the Java code. <i>
</i></p>
<blockquote>
<p>//denominator = field.multiply(denominator,<br/>
// GenericGF.addOrSubtract(1,
field.multiply(errorLocations[j], xiInverse)));<br/>
// Above should work but fails on some Apple and Linux JDKs due
to a Hotspot bug.<br/>
// Below is a funny-looking workaround from Steven Parkes<br/>
<i>int term = field.multiply(errorLocations[j], xiInverse);</i><i><br/>
</i><i>int termPlus1 = (term & 0x1) == 0 ? term | 1 : term
& ~1;</i><i><br/>
</i><i>denominator = field.multiply(denominator, termPlus1);</i></p>
</blockquote>
-- <br/>
<div class="moz-signature">---<br/>
Kindly,<br/>
Robert<br/>
<br/>
<br/>
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