Article View: comp.os.msdos.programmer
Article #4535Re: Microsoft C actually does something better!
From: Kevin D. Quitt
Date: Tue, 05 Feb 1991 18:40
Date: Tue, 05 Feb 1991 18:40
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1822 bytes
In article <1991Feb5.020455.26710@maytag.waterloo.edu> dmurdoch@watstat.waterloo.edu (Duncan Murdoch) writes:
>In article <8904@sail.LABS.TEK.COM> toma@sail.LABS.TEK.COM (Tom Almy) writes:
>>Microsoft C has been bad-mouthed here by myself and others over the years,
>>but this past weekend I discovered at least one place where it beats the
>>major competition -- the math library. Two cases:
>>
>>Case 1: { double x=1e200; printf("%g",x*x); }
>>(With some compilers, the 80x87 has to have the overflow trap masked off).
>
>I tried your tests in Turbo Pascal 6.0, and was pleasantly surprised at the
>results. (TP 6.0 has some real problems with esoteric floating point code.)
>>
>>Microsoft C (V6.00A): prints +inf (correct!)
>
>MSC may be correct for C, but TP prints 1.00000000E+0400, which is even more
>correct. (This is because TP promotes expressions to the 10 byte extended
>type.) When I forced the result to go into a double, I got an overflow
>error; when I masked those, I got INF.
It's more correct mathematically, but not according to the C language
spec. There *are* (non-standard) ways in MSC to use the 10-byte reals.
--
_
Kevin D. Quitt demott!kdq kdq@demott.com
DeMott Electronics Co. 14707 Keswick St. Van Nuys, CA 91405-1266
VOICE (818) 988-4975 FAX (818) 997-1190 MODEM (818) 997-4496 PEP last
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!usc!srhqla!demott!kdq From: kdq@demott.com (Kevin D. Quitt) Newsgroups: comp.os.msdos.programmer Subject: Re: Microsoft C actually does something better! Message-ID: <1991Feb5.184015.9539@demott.com> Date: 5 Feb 91 18:40:15 GMT References: <8904@sail.LABS.TEK.COM> <1991Feb5.020455.26710@maytag.waterloo.edu> Organization: DeMott Electronics Co., Van Nuys CA Lines: 26