[Openmcl-devel] Wrong multiplication

Waldek Hebisch hebisch at math.uni.wroc.pl
Sat Jan 5 14:40:24 PST 2013

> >>>>> "gb" == Gary Byers <gb at clozure.com> writes:
>   gb> (* most-negative-fixnum some-bignum) ; either arg order
>   gb> 
>   gb> will produce an incorrect result on all architectures that CCL runs on.
>   gb> (The incorrect result will also likely differ on each invocation.)
>   gb> 
>   gb> The bad news: this bug has likely been around forever.
>   This really is quite astonishing! CCL has been around for 25 years; it has
>   been considered as a platform for use in space; it is used intensively
>   as a theorem prover (ACL2) runtime; I assume that people have run
>   the Maxima test suite on it. I myself have run many days worth of random
>   integer testing. And noone had detected the bug until now ...

FYI, this bug showed up in FriCAS testsuite.  While I have run FriCAS
tests several times on 64-bit Closure CL, apparently this is first
time when somebody looked at test results on 32-bit Closure CL.

                              Waldek Hebisch
hebisch at math.uni.wroc.pl 

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