Mail Archives: djgpp/1997/01/07/19:40:42
On Mon, 6 Jan 1997, Paul Shirley wrote:
[...]
> First: floating point is slower at add and subtracts. If all you ever do
> is add/sub then integer will be 2* faster *at least*. If you use
> multiplies floating point is ~4-12* faster. Pipelined you get that 12*
> speedup.
> Divides are slightly faster in fpu but a lot less hassle than fixed
> point. If you use single precision fpu mode they are always 2* faster.
> Also its possible to continue issuing integer instructions while a float
> divide executes. That allows tricks like performing a perspective divide
> in effectively 1 clk.
[...]
is this true for 486's? or just Pentiums? i'm hacking at some MPEG audio
code (MAPLAY -- UNIX-based really) so that it can run faster on 486's (the
generic MAPLAY chokes on anything less than a Pentium-60) and I would love
to learn about quickie speedups of FP code.
thanks
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| Orlando Andico email: orly AT gibson DOT eee DOT upd DOT edu DOT ph |
| IRC Lab/EE Dept/UP Diliman http://gibson.eee.upd.edu.ph/~orly |
| "through adventure we are not adventuresome" -- 10000 Maniacs |
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