Mail Archives: djgpp/1998/09/15/20:15:57
>I heard that gcc 2.8.1 (djgpp) supports the -mpentium command, if so, what
>benifits does it give?
Well, theoretically gcc should be able to provide code that runs better on a
pentium than it would otherwise when given that option. Gcc has a cost
table for various operations (add, shift, mul, div, ...) and it selects one
based on what cpu you tell it to use. It helps it make decisions when you
write something like x*320. It can determine whether it would be faster to
do some lea and adds and shifts or to just do a mul. There is also a -march
command (which more the pentium is a noop) but if you ask for 486 you will
enable gcc to use bswap, and if you do ppro it will be able to use the
conditional move instructions. This will generate code that doesn't run on
an earlier version of the cpu.
>Also when is djgpp going to officially support optimizations for the
pentium?
Doubtful ever. I think cygnus is adding some ppro specific stuff, which may
benefit pentium also.
> PGCC is cool, but doesn't support djgpp (using gcc 2.8.1)
PGCC is its own complete compiler environment. It will never 'support' gcc
2.8.1 or any other version of gcc. It is equivalent to it, but with the
pentium optimizations.
, so what's a
>person to do?
>
>
>Also is -fstrength-reduce stable yet? I heard it is, and it isn't. What's
>up?
>
>tom
>
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