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Subject: Re: IA-64 vs OOOE (attn Taylor, Hyatt)

Author: Matt Taylor

Date: 23:19:04 02/11/03

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On February 11, 2003 at 22:39:48, Robert Hyatt wrote:

<snip>
>And I believe the VC _will_ produce CMOV instructions, but you have to
>specifically tell it to produce p6 code only, not something that will run
>on all architectures.  Intel produces them, or at least it did the last time
>I spent any effort looking at .s output...  GCC also does this and has caused
>some problems for me for early AMDs that didn't support CMOV...

I used the /G6 option in VC 7 -- optimize for Pentium Pro. Out of the help
files, it says this sets _M_IX86 to 600. Presumably it would enable Pentium Pro
instructions. I see no other relevant options.

I don't know if I have ever claimed that GCC does not generate cmov, but I
discovered a couple days ago that it does. GCC's default target is the 386, and
that obviously didn't have cmov, so it normally doesn't generate cmov. I should
have realized that I needed to do -march=athlon. Doh!

>BTW if you didn't read, posts were somehow dropped into /dev/null by some
>sort of glitch.  Whether they have come back or not I have not yet checked...

That's pretty funny. Oh well.

-Matt



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