When compiling via gcc, there's the __builtin_prefetch function:

http://gcc.gnu.org/onlinedocs/gcc-3.3.3/gcc/Other-Builtins.html (about 2/3rds of the way down the page)

Thanks, I wasn't aware of that.

see also: http://gcc.gnu.org/projects/prefetch.html

I didn't read it very carefully, but it's not clear (on the x86 cpus) if there is a prefetch instruction that is common between the amd & intel flavours, ie would a ghc binary with prefetch be portable between P3/P4/Athlon.

P3/P4 and Athlon have different prefetch instructions. However, Athlon64 supports the P3/P4 instructions. Cheers, Simon