Path: chuka.playstation.co.uk!news
From: "pal" <pal_news@hotmail.com>
Newsgroups: scee.yaroze.freetalk.english
Subject: Re: Daft Question [long]
Date: 2 Sep 2001 22:28:11 GMT
Organization: PlayStation Net Yaroze (SCEE)
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Steven Osman <sosman@terratron.com> wrote in article
<3b9250e6.158216893@www.netyaroze-europe.com>...
><snip>Remember that the processor can take UP TO 32 cycles...  presumably,
>that would be if it has to do a tonne of additions<snip>

Indeed according to mips docs it processes 1bit per cycle; a whole mul/div
always takes 32 cycles (although I don't know whether mul/divs can be done
less-than-32bit-ly) or a bit more depending on instruction variants. What
is meant by "up to" is that, as mul/divs are processed in parallel in
something like a second dedicated alu, other instructions can be executed
until the result of the mul/div is actually used.
Ie if you have something like:
a *= b
x += y
x += a
the first line will be executed in parallel with the second, so that those
first two lines will take 32 cycles.
In the following order however the first two lines would take 1+32 cycles:
x += y
a *= b
x += a