diff options
| -rw-r--r-- | arch/arm/include/asm/bitops.h | 92 |
1 files changed, 9 insertions, 83 deletions
diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h index 4cab9bb823fb..c92e42a5c8f7 100644 --- a/arch/arm/include/asm/bitops.h +++ b/arch/arm/include/asm/bitops.h @@ -215,7 +215,6 @@ extern int _find_next_bit_be(const unsigned long *p, int size, int offset); #if __LINUX_ARM_ARCH__ < 5 -#include <asm-generic/bitops/ffz.h> #include <asm-generic/bitops/__fls.h> #include <asm-generic/bitops/__ffs.h> #include <asm-generic/bitops/fls.h> @@ -223,93 +222,20 @@ extern int _find_next_bit_be(const unsigned long *p, int size, int offset); #else -static inline int constant_fls(int x) -{ - int r = 32; - - if (!x) - return 0; - if (!(x & 0xffff0000u)) { - x <<= 16; - r -= 16; - } - if (!(x & 0xff000000u)) { - x <<= 8; - r -= 8; - } - if (!(x & 0xf0000000u)) { - x <<= 4; - r -= 4; - } - if (!(x & 0xc0000000u)) { - x <<= 2; - r -= 2; - } - if (!(x & 0x80000000u)) { - x <<= 1; - r -= 1; - } - return r; -} - -/* - * On ARMv5 and above those functions can be implemented around the - * clz instruction for much better code efficiency. __clz returns - * the number of leading zeros, zero input will return 32, and - * 0x80000000 will return 0. - */ -static inline unsigned int __clz(unsigned int x) -{ - unsigned int ret; - - asm("clz\t%0, %1" : "=r" (ret) : "r" (x)); - - return ret; -} - -/* - * fls() returns zero if the input is zero, otherwise returns the bit - * position of the last set bit, where the LSB is 1 and MSB is 32. - */ -static inline int fls(int x) -{ - if (__builtin_constant_p(x)) - return constant_fls(x); - - return 32 - __clz(x); -} - -/* - * __fls() returns the bit position of the last bit set, where the - * LSB is 0 and MSB is 31. Zero input is undefined. - */ -static inline unsigned long __fls(unsigned long x) -{ - return fls(x) - 1; -} - -/* - * ffs() returns zero if the input was zero, otherwise returns the bit - * position of the first set bit, where the LSB is 1 and MSB is 32. - */ -static inline int ffs(int x) -{ - return fls(x & -x); -} - /* - * __ffs() returns the bit position of the first bit set, where the - * LSB is 0 and MSB is 31. Zero input is undefined. + * On ARMv5 and above, the gcc built-ins may rely on the clz instruction + * and produce optimal inlined code in all cases. On ARMv7 it is even + * better by also using the rbit instruction. */ -static inline unsigned long __ffs(unsigned long x) -{ - return ffs(x) - 1; -} - -#define ffz(x) __ffs( ~(x) ) +#include <asm-generic/bitops/builtin-__fls.h> +#include <asm-generic/bitops/builtin-__ffs.h> +#include <asm-generic/bitops/builtin-fls.h> +#include <asm-generic/bitops/builtin-ffs.h> #endif +#include <asm-generic/bitops/ffz.h> + #include <asm-generic/bitops/fls64.h> #include <asm-generic/bitops/sched.h> |