recent commit to pirofti made me wonder why don't we take an advantage
of the 64 bit bswap instruction on amd64?
Index: arch/amd64/include/endian.h
===================================================================
RCS file: /home/cvs/src/sys/arch/amd64/include/endian.h,v
retrieving revision 1.3
diff -u -p -r1.3 endian.h
--- arch/amd64/include/endian.h 13 Dec 2005 00:35:22 -0000 1.3
+++ arch/amd64/include/endian.h 11 Mar 2011 15:47:40 -0000
@@ -36,12 +36,11 @@
__swap32md_x; \
})
-/* XXX - I'm sure there is a better way on this cpu. */
#define __swap64md(x) ({
\
u_int64_t __swap64md_x = (x); \
\
- (u_int64_t)__swap32md(__swap64md_x >> 32) | \
- (u_int64_t)__swap32md(__swap64md_x & 0xffffffff) << 32; \
+ __asm ("bswapq %1" : "+r" (__swap64md_x)); \
+ __swap64md_x; \
})
#define __swap16md(x) ({
\
