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PPC: Added fls, fls64, __ilog2_u64, and ffs64 to bitops

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fls64, __ilog2_u64, ffs64 are variants that work on an u64,
and fls is used to implement them.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This commit is contained in:
Kumar Gala 2008-06-11 10:14:06 -05:00 committed by Wolfgang Denk
parent 83002a77cb
commit 4928e97c85
1 changed files with 52 additions and 0 deletions
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52
include/asm-ppc/bitops.h
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@ -152,6 +152,7 @@ extern __inline__ int test_bit(int nr, __const__ volatile void *addr)
}
/* Return the bit position of the most significant 1 bit in a word */
/* - the result is undefined when x == 0 */
extern __inline__ int __ilog2(unsigned int x)
{
int lz;
@ -167,6 +168,57 @@ extern __inline__ int ffz(unsigned int x)
return __ilog2(x & -x);
}
/*
* fls: find last (most-significant) bit set.
* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
*
* On powerpc, __ilog2(0) returns -1, but this is not safe in general
*/
static __inline__ int fls(unsigned int x)
{
return __ilog2(x) + 1;
}
/**
* fls64 - find last set bit in a 64-bit word
* @x: the word to search
*
* This is defined in a similar way as the libc and compiler builtin
* ffsll, but returns the position of the most significant set bit.
*
* fls64(value) returns 0 if value is 0 or the position of the last
* set bit if value is nonzero. The last (most significant) bit is
* at position 64.
*/
#if BITS_PER_LONG == 32
static inline int fls64(__u64 x)
{
__u32 h = x >> 32;
if (h)
return fls(h) + 32;
return fls(x);
}
#elif BITS_PER_LONG == 64
static inline int fls64(__u64 x)
{
if (x == 0)
return 0;
return __ilog2(x) + 1;
}
#else
#error BITS_PER_LONG not 32 or 64
#endif
static inline int __ilog2_u64(u64 n)
{
return fls64(n) - 1;
}
static inline int ffs64(u64 x)
{
return __ilog2_u64(x & -x) + 1ull;
}
#ifdef __KERNEL__
/*