From 06fbefd10046a0fae7e588b7c6d25fb51811b931 Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Wed, 19 Apr 2017 00:20:54 +0200 Subject: add a_clz_64 helper function counts leading zero bits of a 64bit int, undefined on zero input. (has nothing to do with atomics, added to atomic.h so target specific helper functions are together.) there is a logarithmic generic implementation and another in terms of a 32bit a_clz_32 on targets where that's available. --- arch/powerpc/atomic_arch.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/powerpc') diff --git a/arch/powerpc/atomic_arch.h b/arch/powerpc/atomic_arch.h index f31566b2..5b65cde7 100644 --- a/arch/powerpc/atomic_arch.h +++ b/arch/powerpc/atomic_arch.h @@ -37,3 +37,10 @@ static inline void a_store(volatile int *p, int v) *p = v; a_post_llsc(); } + +#define a_clz_32 a_clz_32 +static inline int a_clz_32(uint32_t x) +{ + __asm__ ("cntlzw %0, %1" : "=r"(x) : "r"(x)); + return x; +} -- cgit v1.2.1