path: root/scripts/Makefile.lib
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authorBorislav Petkov <borislav.petkov@amd.com>2010-03-05 17:34:46 +0100
committerH. Peter Anvin <hpa@zytor.com>2010-04-06 15:52:11 -0700
commitd61931d89be506372d01a90d1755f6d0a9fafe2d (patch)
tree652c34238edcb6c558163abc3cd9d6ce7c5f91a5 /scripts/Makefile.lib
parent1527bc8b928dd1399c3d3467dd47d9ede210978a (diff)
x86: Add optimized popcnt variants
Add support for the hardware version of the Hamming weight function, popcnt, present in CPUs which advertize it under CPUID, Function 0x0000_0001_ECX[23]. On CPUs which don't support it, we fallback to the default lib/hweight.c sw versions. A synthetic benchmark comparing popcnt with __sw_hweight64 showed almost a 3x speedup on a F10h machine. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> LKML-Reference: <20100318112015.GC11152@aftab> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'scripts/Makefile.lib')
1 files changed, 4 insertions, 0 deletions
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index f9bdf264473d..cbcd654215e6 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -245,3 +245,7 @@ quiet_cmd_lzo = LZO $@
cmd_lzo = (cat $(filter-out FORCE,$^) | \
lzop -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
(rm -f $@ ; false)
+# misc stuff
+# ---------------------------------------------------------------------------

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