Message-ID: <320F3542.2180@pobox.oleane.com> Date: Mon, 12 Aug 1996 15:44:34 +0200 From: Francois Charton Organization: CCMSA MIME-Version: 1.0 To: Hans-Bernhard Broeker CC: djgpp AT delorie DOT com Subject: Re: Re : Compiling povray 3.0 with djgpp 2.0 References: <199608121316 DOT PAA12374 AT acp3bf DOT physik DOT rwth-aachen DOT de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hans-Bernhard Broeker wrote: > > Could you please diagnose this a bit further? > Sorry, I did it but forgot to post the info : I had one in "pow" function, actually in __ieee_754_pow() function from libm.a. I also got an exception somewhere else because I reprogrammed povray *not* to use pow (replacing pow(x,y) by exp(y*log(x))) and got another exception when compiling with optimisation on... (however, I didn't keep the corresponding source and executable). On the pow problem, I posted something yesterday : which seems to hint a defect in libm.a pow() function. > Generally, I'd suggest to turn off fp exceptions for something like a > raytracing program, that doesn't actually handle this kind of errors > anyway, probably. See 'info libc alpha _control87' for details. This sounds like "hiding the dust under the carpet"... fp exception happen because something wrong is happening, probably because either the math libraries or the calculation algorithms you use do not handle some special case, or have a bug in it. If it is the case, the result of the calculations may be wrong... Regards, F. Charton