x86: merge the simple bitops and move them to bitops.h
Some of those can be written in such a way that the same
inline assembly can be used to generate both 32 bit and
64 bit code.
For ffs and fls, x86_64 unconditionally used the cmov
instruction and i386 unconditionally used a conditional
branch over a mov instruction. In the current patch I
chose to select the version based on the availability
of the cmov instruction instead. A small detail here is
that x86_64 did not previously set CONFIG_X86_CMOV=y.
Improved comments for ffs, ffz, fls and variations.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 4da3cdb..cf3ff2c 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -398,7 +398,7 @@
# generates cmov.
config X86_CMOV
def_bool y
- depends on (MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7)
+ depends on (MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || X86_64)
config X86_MINIMUM_CPU_FAMILY
int