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bswap on prescott
- From: "Török Edvin" <edwintorok at gmail dot com>
- To: libc-alpha at sourceware dot org
- Date: Wed, 24 Jan 2007 23:26:44 +0200
- Subject: bswap on prescott
Hi,
If I compile a program using ntohl with '-march=prescott -O2', I get 3
ror instr., however if I compile it with '-march=pentium4 -O2', I get
the bswap instr.
Looking at bits/byteswap.h, it seems that prescott is missing from the list:
# if __WORDSIZE == 64 || (defined __i486__ || defined __pentium__ \
|| defined __pentiumpro__ || defined __pentium4__ \
|| defined __k8__ || defined __athlon__ \
|| defined __k6__)
[...]
__asm__ ("bswap %0",...
Is this intended behaviour? Which is faster on prescott: bswap, or the
3 rotations?
Best regards,
Edwin