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| author | Fabio Estevam <fabio.estevam@freescale.com> | 2015-11-05 14:43:23 (GMT) |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2015-11-05 15:51:57 (GMT) |
| commit | 77c8554e4d7db8d04f03ee92d186bd87f74e3773 (patch) | |
| tree | 709b900ed22641760b41ca9880679eab2b36c2eb /include/asm-generic/bitops/__fls.h | |
| parent | f598e7a99eda286d4c0883e440b5f81c8ac050f3 (diff) | |
| download | u-boot-77c8554e4d7db8d04f03ee92d186bd87f74e3773.tar.xz | |
include: Add generic bitops headers
Use the generic bitops header files from the kernel.
Imported from kernel 4.2.3.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
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 0000000..a60a7cc --- /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_ */ |