pjones@samba.acs.unc.edu (paul jones) (09/19/90)
Does anyone have a good reference for MAC Co-Processors?
I have heard of one called the Sane co-processor and would
like more information on this and any other MAC co-processors.
Please reply to email:
knott@conga.acs.unc.edu
Thanks!fiddler@concertina.Eng.Sun.COM (Steve Hix) (09/20/90)
In article <1104@beguine.UUCP>, pjones@samba.acs.unc.edu (paul jones) writes: > > Does anyone have a good reference for MAC Co-Processors? > I have heard of one called the Sane co-processor and would > like more information on this and any other MAC co-processors. SANE is the Standard Apple Numerics Engine. Essentially implements the IEEE floating-point numeric standard for various Apple computers. That means for everything from the Apple II to the Mac. For anything of Apple's that doesn't have a math coprocessor, this is the way to get good numerics...a bit slow, perhaps, compared to a 68882, but you will at least know how correct your math is going to be, and the degree of error therein. On the other hand, you *could* look at a 68881/68882 as a SANE coprocessor...they do pretty much the same job. -- ------------ The only drawback with morning is that it comes at such an inconvenient time of day. ------------
philip@pescadero.Stanford.EDU (Philip Machanick) (09/20/90)
In article <142737@sun.Eng.Sun.COM>, fiddler@concertina.Eng.Sun.COM (Steve Hix) writes: [...] > On the other hand, you *could* look at a 68881/68882 as a SANE > coprocessor...they do pretty much the same job. Sort of - but SANE even with a 68881/6882 is about 20 times slower than code run directly on the coprocessor. Apple maintains some of their routines are more accurate than the IEEE standard, and this justifies the slowness. Philip Machanick philip@pescadero.stanford.edu
fiddler@concertina.Eng.Sun.COM (Steve Hix) (09/21/90)
In article <1990Sep19.230715.15188@Neon.Stanford.EDU>, philip@pescadero.Stanford.EDU (Philip Machanick) writes: > In article <142737@sun.Eng.Sun.COM>, fiddler@concertina.Eng.Sun.COM > (Steve Hix) writes: > [...] > > On the other hand, you *could* look at a 68881/68882 as a SANE > > coprocessor...they do pretty much the same job. > > Sort of - but SANE even with a 68881/6882 is about 20 times slower than > code run directly on the coprocessor. Apple maintains some of their routines are more > accurate than the IEEE standard, and this justifies the slowness. I thought that that went without saying. Apparently not. If you can't run a 68881/2 on your machine, SANE is about the only game in town. (Even then, you'll end up dealing with one application's or another's own math usage, if they don't use SANE or a math coprocessor. Like Microsoft.) Btw, some of the team that developed SANE at Apple were on the IEEE committee that developed the floating-point standard. Don't forget, even under SANE or an '881/2, there will still be some degree of error in a greater or lesser portion of your math results. At least with SANE or some other IEEE-compliant floating point option, you'll know how much error there is. -- ------------ The only drawback with morning is that it comes at such an inconvenient time of day. ------------