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| author |   Alexander van Heukelum <heukelum@mailshack.com> | 2008-03-15 18:31:49 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2008-04-26 19:21:16 +0200 |
| commit | 56a6b1eb7bfb5ace0b5cb9c149f502fbd101b8ab (patch) | |
| tree | 46d3781050938b0649fc89cd8e7f612cacb66984 /include/asm-ia64 | |
| parent | generic: introduce a generic __fls implementation (diff) | |
| download | linux-dev-56a6b1eb7bfb5ace0b5cb9c149f502fbd101b8ab.tar.xz linux-dev-56a6b1eb7bfb5ace0b5cb9c149f502fbd101b8ab.zip | |
generic: implement __fls on all 64-bit archs
Implement __fls on all 64-bit archs:
alpha has an implementation of fls64.
Added __fls(x) = fls64(x) - 1.
ia64 has fls, but not __fls.
Added __fls based on code of fls.
mips and powerpc have __ilog2, which is the same as __fls.
Added __fls = __ilog2.
parisc, s390, sh and sparc64:
Include generic __fls.
x86_64 already has __fls.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-ia64')
| -rw-r--r-- | include/asm-ia64/bitops.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/asm-ia64/bitops.h b/include/asm-ia64/bitops.h index 953d3df9dd22..e2ca80037335 100644 --- a/include/asm-ia64/bitops.h +++ b/include/asm-ia64/bitops.h @@ -407,6 +407,22 @@ fls (int t) return ia64_popcnt(x); } +/* + * Find the last (most significant) bit set. Undefined for x==0. + * Bits are numbered from 0..63 (e.g., __fls(9) == 3). + */ +static inline unsigned long +__fls (unsigned long x) +{ + x |= x >> 1; + x |= x >> 2; + x |= x >> 4; + x |= x >> 8; + x |= x >> 16; + x |= x >> 32; + return ia64_popcnt(x) - 1; +} + #include <asm-generic/bitops/fls64.h> /* |