path: root/lib/Makefile
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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 /lib/Makefile
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 'lib/Makefile')
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/Makefile b/lib/Makefile
index 2e152aed7198..abe63a8ad143 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -39,7 +39,10 @@ lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
lib-$(CONFIG_GENERIC_FIND_FIRST_BIT) += find_next_bit.o
lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
obj-$(CONFIG_GENERIC_FIND_LAST_BIT) += find_last_bit.o
+CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS))
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
obj-$(CONFIG_BTREE) += btree.o
obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o

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