[PATCH 2/5] ARM: findbit: provide more efficient ARMv7 implementation

[Russell King (Oracle)]

Provide a more efficient ARMv7 implementation to determine the first
set bit in the supplied value.

Signed-off-by: Russell King (Oracle) <rmk at armlinux.org.uk>
---
 arch/arm/lib/findbit.S | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S
index 4c584bc4704b..256e095d490b 100644
--- a/arch/arm/lib/findbit.S
+++ b/arch/arm/lib/findbit.S
@@ -170,7 +170,11 @@ ENDPROC(_find_next_bit_be)
  * One or more bits in the LSB of r3 are assumed to be set.
  */
 .L_found:
-#if __LINUX_ARM_ARCH__ >= 5
+#if __LINUX_ARM_ARCH__ >= 7
+		rbit	r3, r3			@ reverse bits
+		clz	r3, r3			@ count high zero bits
+		add	r0, r2, r3		@ add offset of first set bit
+#elif __LINUX_ARM_ARCH__ >= 5
 		rsb	r0, r3, #0
 		and	r3, r3, r0		@ mask out lowest bit set
 		clz	r3, r3			@ count high zero bits
-- 
2.30.2