KUO@oregon.uoregon.edu (Shijong Kuo) (02/23/90)
According to an article on 68040 in lateset DDJ, Motorola omitted floating point intructions for transcendental functions with their new CPU. Perhaps the 3.5 MFLOPS rating touted by Motorola shouldn't be taken seriously! kuo@oregon.uoregon.edu Why shouldn't everybody try to "mess up" the $50,000 ceiling of F.I.C.A.
melling@cs.psu.edu (Michael D Mellinger) (02/24/90)
In article <16342@oregon.uoregon.edu> KUO@oregon.uoregon.edu (Shijong Kuo) writes:
According to an article on 68040 in lateset DDJ, Motorola omitted
floating point intructions for transcendental functions with their new CPU.
Perhaps the 3.5 MFLOPS rating touted by Motorola shouldn't be taken seriously!
kuo@oregon.uoregon.edu
Why shouldn't everybody try to "mess up" the $50,000 ceiling of F.I.C.A.
In the lastest issue of Byte, they state that even though the
transcendenatal functions are simulated in software a 25%(might be wrong) to
100% increase can still be expected over the 68882.
- Mikedaveh@cbmvax.commodore.com (Dave Haynie) (02/27/90)
In article <16342@oregon.uoregon.edu> KUO@oregon.uoregon.edu (Shijong Kuo) writes: >According to an article on 68040 in lateset DDJ, Motorola omitted >floating point intructions for transcendental functions with their new CPU. Yup, the transcendentals are serviced by instruction trap routines. Their claim is that it'll still be better than twice the speed of an '882 for these ops. The FPU logic apparently does some cooking of the operands before trapping. >Perhaps the 3.5 MFLOPS rating touted by Motorola shouldn't be taken seriously! They are calling for a 3 clock FP add and 5 clock FP multiply. That's 120ns and 200ns, respectively. If you just ran additions, that would put you somewhere around 8 MFLOPS. Sounds like the instruction mix is pretty important, though if you think about it, hasn't it always been? The 3.5 figure was taken from some benchmark code. As with most things, a real life 68040 machine running a real OS and some real benchmarks will do wonders to clear these things up. >kuo@oregon.uoregon.edu -- Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Too much of everything is just enough