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author | Stefano Babic <sbabic@denx.de> | 2015-11-12 17:13:26 +0100 |
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committer | Stefano Babic <sbabic@denx.de> | 2015-11-12 17:13:26 +0100 |
commit | 5f5620ab2679608f94b3a77e51c77d0a770103bd (patch) | |
tree | ec983c06d2f62384909968bb870add121b8a1502 /include/asm-generic/bitops/__fls.h | |
parent | 78e9ca52edaab74ad645d719676ff4c24d2f462c (diff) | |
parent | 038be18fd95aa6283eafb85ceabc0b880976424b (diff) |
Merge git://git.denx.de/u-boot
Diffstat (limited to 'include/asm-generic/bitops/__fls.h')
-rw-r--r-- | include/asm-generic/bitops/__fls.h | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/include/asm-generic/bitops/__fls.h b/include/asm-generic/bitops/__fls.h new file mode 100644 index 0000000000..a60a7ccb67 --- /dev/null +++ b/include/asm-generic/bitops/__fls.h @@ -0,0 +1,43 @@ +#ifndef _ASM_GENERIC_BITOPS___FLS_H_ +#define _ASM_GENERIC_BITOPS___FLS_H_ + +#include <asm/types.h> + +/** + * __fls - find last (most-significant) set bit in a long word + * @word: the word to search + * + * Undefined if no set bit exists, so code should check against 0 first. + */ +static __always_inline unsigned long __fls(unsigned long word) +{ + int num = BITS_PER_LONG - 1; + +#if BITS_PER_LONG == 64 + if (!(word & (~0ul << 32))) { + num -= 32; + word <<= 32; + } +#endif + if (!(word & (~0ul << (BITS_PER_LONG-16)))) { + num -= 16; + word <<= 16; + } + if (!(word & (~0ul << (BITS_PER_LONG-8)))) { + num -= 8; + word <<= 8; + } + if (!(word & (~0ul << (BITS_PER_LONG-4)))) { + num -= 4; + word <<= 4; + } + if (!(word & (~0ul << (BITS_PER_LONG-2)))) { + num -= 2; + word <<= 2; + } + if (!(word & (~0ul << (BITS_PER_LONG-1)))) + num -= 1; + return num; +} + +#endif /* _ASM_GENERIC_BITOPS___FLS_H_ */ |