milo@ndmath.UUCP (Greg Corson) (12/08/86)
I have been working on a porting a large fortran (don't flame me...I didn't write it) graphics package to the Mac. Recently I had a chance to run it on a Hyperdrive 2000 system which has the 68881 floating point chip. The program was compiled in Microsoft (aka Absoft) Fortran 77. The problem is that there does not appear to be a way to get Microsoft Fortran to recognize the floating point chip! Hyperdrive patches the SANE calls to use the 68881 floating point but Microsoft fortran does not call SANE (it has it's own floating point library). A "use hardware floating point" option is briefly mentioned in the manual, however this option has been removed from the options dialog box in the Mac version of the compiler so it can't be used. The graphics program (a hidden-line/surface package) does all its math in floating point so I am sure the use of the floating point chip would be a big help. Can anyone at Microsoft/Absoft/Apple/Hyperdrive tell me how to get Microsoft Fortran to recognize the floating point chip? Greg Corson ...seismo!iuvax!kangaro!milo
rs4u#@ANDREW.CMU.EDU (Richard Siegel) (12/09/86)
[Line-Eater? What Line-Eater? *Chomp* 8-) ]
Organization: Carnegie-Mellon University, Pittsburgh, Pa.
Position: Confused Undergraduate
To get MS/Absoft Fortran to use the 68881, you need to purchase from {Absoft,
Microsoft} a version of the compiler that includes a library that does the
68881 calls instead of the Absoft floating-point package. I believe you can
purchase that library separately, or as part of MacFortran/020, which is a
68020 Fortran compiler.
Sorry, I can't help as to the price...
By the way, MacFortran's floating-point performance on a regular Macintosh is
simply INCREDIBLE; it's on the order of 10 times faster than SANE at {x, /,
+, -}; I'm not sure of the improvement for transcendentals. It's a shame that
those routines can't be used by other programs, perhaps in place of the
regular SANE package...
Good luck!
--Rich
Richard M. Siegel
Arpanet: rs4u@andrew.cmu.edu (the only way to get to me!)
Disclaimer --> Disclaimers are bogus.