diff options
| author | David Howells <dhowells@redhat.com> | 2006-09-25 23:32:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-26 08:48:54 -0700 |
| commit | a8ad27d03f17e6154c61e81d4a7028c56ca6390d (patch) | |
| tree | 14d0367af1fafa359733b04326a95a4fe39557c5 | |
| parent | 92fc707208bb2e601c24b5ab65db37bcb361b658 (diff) | |
| download | linux-a8ad27d03f17e6154c61e81d4a7028c56ca6390d.tar.bz2 | |
[PATCH] FRV: Implement fls64()
Implement fls64() for FRV without recource to conditional jumps.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | include/asm-frv/bitops.h | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/include/asm-frv/bitops.h b/include/asm-frv/bitops.h index 97fb746f76c7..591eecc1f8cd 100644 --- a/include/asm-frv/bitops.h +++ b/include/asm-frv/bitops.h @@ -186,7 +186,47 @@ static inline int __test_bit(int nr, const volatile void * addr) bit; \ }) -#include <asm-generic/bitops/fls64.h> +/** + * fls64 - find last bit set in a 64-bit value + * @n: the value to search + * + * This is defined the same way as ffs: + * - return 64..1 to indicate bit 63..0 most significant bit set + * - return 0 to indicate no bits set + */ +static inline __attribute__((const)) +int fls64(u64 n) +{ + union { + u64 ll; + struct { u32 h, l; }; + } _; + int bit, x, y; + + _.ll = n; + + asm(" subcc.p %3,gr0,gr0,icc0 \n" + " subcc %4,gr0,gr0,icc1 \n" + " ckne icc0,cc4 \n" + " ckne icc1,cc5 \n" + " norcr cc4,cc5,cc6 \n" + " csub.p %0,%0,%0 ,cc6,1 \n" + " orcr cc5,cc4,cc4 \n" + " andcr cc4,cc5,cc4 \n" + " cscan.p %3,gr0,%0 ,cc4,0 \n" + " setlos #64,%1 \n" + " cscan.p %4,gr0,%0 ,cc4,1 \n" + " setlos #32,%2 \n" + " csub.p %1,%0,%0 ,cc4,0 \n" + " csub %2,%0,%0 ,cc4,1 \n" + : "=&r"(bit), "=r"(x), "=r"(y) + : "0r"(_.h), "r"(_.l) + : "icc0", "icc1", "cc4", "cc5", "cc6" + ); + return bit; + +} + #include <asm-generic/bitops/sched.h> #include <asm-generic/bitops/hweight.h> |