Date: Sun, 5 Oct 1997 15:56:31 +1000 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, reilly@zeta.org.au Cc: freebsd-current@FreeBSD.ORG, rcarter@consys.com Subject: Re: xlock: caught signal 8 while running galaxy mode. Message-ID: <199710050556.PAA20163@godzilla.zeta.org.au>
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>after all), but all I can say is Bah, Humbug! I do numerical (DSP) work >all the time, and I'd much rather the floating point maths was >absolutely as fast as it possibly could be, rather than worrying about But you would rather not write it all in assembler? :-) >the last few bits of precision. I usually work with 32-bit floats >anyway. Consistency of floating point results is a myth, and >dependance on every bit of precision, and rounding modes is algorithmic >error. IEEE floating point is consistent, and some algorithms depend on it. >I recently tried to port some speech recognition code that runs fine on >two different DSPs, a Dec Alpha, a Sparc and a SCO Pentium box to my >FreeBSD machine. The HMM is expected to underflow all the time. In >the brief time I had available, I could not figure out how to stop the >FreeBSD maths from trapping at that point, and I couldn't write a trap >handler that would ignore the error and continue, so I gave up. So Do you mean overflow? FreeBSD masks underflow, denormal and precision exceptions by default. Continuing from SIGFPE handlers is much harder than masking FP exceptions, at least on i386's. Bruce
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