From: kagel AT quasar DOT bloomberg DOT com Date: Thu, 6 Feb 1997 10:46:31 -0500 Message-Id: <9702061546.AA26462@quasar.bloomberg.com > To: eliz AT is DOT elta DOT co DOT il Cc: myskin AT inp DOT nsk DOT su, djgpp AT delorie DOT com In-Reply-To: (message from Eli Zaretskii on Thu, 6 Feb 1997 17:47:21 +0200 (IST)) Subject: Re: double-->int: What's wrong here? Reply-To: kagel AT dg1 DOT bloomberg DOT com Errors-To: postmaster AT ns1 Date: Thu, 6 Feb 1997 17:47:21 +0200 (IST) From: Eli Zaretskii X-Sender: eliz AT is Cc: myskin AT inp DOT nsk DOT su, djgpp AT delorie DOT com Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Content-Length: 1127 On Thu, 6 Feb 1997 kagel AT quasar DOT bloomberg DOT com wrote: > Are you sure? Did you run that small test program with and without + 0.5? > If not, please do. I'm pretty sure it will help. > > Same exact results. BTW I am testing on a DG using GCC I am not home to test > DJGPP on my Cyrix 686 so this may be the difference in internal precision > between the x87 and M88100's MMU. x87 is weird, and its DJGPP setup is not necessarily the most correct one. The code should be run on a PC to be sure. > I'm just saying we do not now enough yet to > dismiss this guy's problem as sloppy floating point source code. I didn't say ``sloppy''. I just wanted to convey my general experience No value judgement intended. that being defensive about FP computations is much more productive than digging deep into the mysteries of x87 trying to understand who is to blame (although there was a time when I did my share of such digging). Right, but I do not think it will help in this case. I WILL try it at home tonight, however, if it is an FPU or emulator issue rather than a code generator issue or even a red herring, I may get different results since my Cyrix 686 MAY return different results from Intel 387, 486, P5, PPro; AMD 486, 586, 686; Cyrix 486, 586 or the emulator. Just as the M88100 MMU on my DG here returns the expected results, unlike myskin's setup. > (BTW I agree with your recommendation in the general case, though, I > usually use 0.505 as an error correction value.) That's for second-graders ;-). First, people need to be convinced to add any value at all. Agreed. -- Art S. Kagel, kagel AT quasar DOT bloomberg DOT com A proverb is no proverb to you 'till life has illustrated it. -- John Keats