As far as I'm aware the SSE2 extensions are available in either mode. SSE2 provided packed 128bit integer arithmetic and 64 bit floating-point SIMD (single instruction multiple data) arithmetic as well as greater cache control and much more.
But to use 64bit integers and the extra registers (8 new GPR's oh the luxury and 8 new SSE2 registers I think) you will need to compile a 64bit .exe on a 64bit operating system.
Cheers,
Matt
-----Original Message-----
From: Peter Shenkin [mailto:[log in to unmask]]
Sent: Thursday, 26 February 2004 11:19 AM
To: [log in to unmask]
Subject: Re: A few Q's about P4 and Opteron optimization...
Hi,
Back to this for a moment.
> Opteron-specific optimizations gain in some applications from use of the
> larger register sets. The floating point units are designed to run as fast
> with scalar instructions as with parallel, in some cases. Still, PGI
> Fortran offers the option to "cache-align" arrays in order to gain
> advantage from parallel instructions. While there is an advantage in these
> optimizations, it's not as great as you appear to be looking for.
> Tim Prince
In general, are Opteron-specific optimizations available only
when compiling 64-bit executables, or when compiling 32-bit
executables as well?
Thanks,
-P.
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