Comment 1 for bug 974406
Revision history for this message
| Christophe Rhodes (csr21-cantab) wrote Re: [Bug 974406] [NEW] Bug in LOGAND (from random testing) | #1 |
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1b1ed1a
(Get the code!)
Christophe Rhodes <email address hidden> writes:
status fixcommitted
done
commit 52b1041d3a14eaa
Author: Christophe Rhodes <email address hidden>
Date: Thu Apr 5 19:55:05 2012 +0100
Fix bug in unsigned modular arithmetic using a signed implementation
If we aim to be clever by implementing an unsigned modular arithmetic
computation using signed arithmetic, we need to make sure that we
don't accidentally contaminate the computation with any extraneous
high bits. This means that we must be sure to cut constants to the
appropriate width, as well as computations, so do so; this fixes
bug #974406 from Paul Dietz. (In addition the change from cutting
to the requested width to the implementation width fixes #903821,
so Go Team!)
Test cases. Minimally horrible test case for #903821; far worse
suggestions were made on #sbcl IRC...