[comp.arch] cycle counts; was Re: R4000 details?????

enbody@ss8.cps.msu.edu (Dr Richard Enbody) (02/06/91)

Michael Slater states
|> 
|> >How many cycles for an integer multiply and divide?
|> 
|> Multiply is half the cycles of an R3000, divide is the same.
|> 
|> >How about the cycle counts for the FP operations?
|> 
|> Mostly the same as for R3000; multiply is 25% faster.  Of course, all are
|> faster because of higher clock rate. (Note cycle count is based on cycles of
|> the 50-MHz external clock, not 100-MHz internal clock, so speedup is by a
|> factor of 50/33, not 100/33, comparing to a 33-MHz R3000/3010.)
|> 
|> 
|> Michael Slater, Editor and Publisher, Microprocessor Report
|> mslater@cup.portal.com   707/823-4004   fax: 707/823-0504

I don't know how many cycles are needed for these operations
in the R3000.  Can anyone fill me in or give them for the R4000?
I am curious about how fast multiplication and division have become
in absolute terms.

For comparison, how many cycles were needed for multiplication and
division on a much older chip, e.g. the original IBM PC (weren't they
done in software?).

Thanks.