Messages in this thread Patch in this message | | | Date | Wed, 01 Feb 2006 18:02:36 +0900 | From | Akinobu Mita <> | Subject | [patch 12/44] generic sched_find_first_bit() |
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This patch introduces the C-language equivalent of the function: int sched_find_first_bit(const unsigned long *b);
In include/asm-generic/bitops/sched.h
This code largely copied from: include/asm-powerpc/bitops.h
Signed-off-by: Akinobu Mita <mita@miraclelinux.com> include/asm-generic/bitops/sched.h | 36 ++++++++++++++++++++++++++++++++++++ 1 files changed, 36 insertions(+)
Index: 2.6-git/include/asm-generic/bitops/sched.h =================================================================== --- /dev/null +++ 2.6-git/include/asm-generic/bitops/sched.h @@ -0,0 +1,36 @@ +#ifndef _ASM_GENERIC_BITOPS_SCHED_H_ +#define _ASM_GENERIC_BITOPS_SCHED_H_ + +#include <linux/compiler.h> /* unlikely() */ +#include <asm/types.h> + +/* + * Every architecture must define this function. It's the fastest + * way of searching a 140-bit bitmap where the first 100 bits are + * unlikely to be set. It's guaranteed that at least one of the 140 + * bits is cleared. + */ +static inline int sched_find_first_bit(const unsigned long *b) +{ +#if BITS_PER_LONG == 64 + if (unlikely(b[0])) + return __ffs(b[0]); + if (unlikely(b[1])) + return __ffs(b[1]) + 64; + return __ffs(b[2]) + 128; +#elif BITS_PER_LONG == 32 + if (unlikely(b[0])) + return __ffs(b[0]); + if (unlikely(b[1])) + return __ffs(b[1]) + 32; + if (unlikely(b[2])) + return __ffs(b[2]) + 64; + if (b[3]) + return __ffs(b[3]) + 96; + return __ffs(b[4]) + 128; +#else +#error BITS_PER_LONG not defined +#endif +} + +#endif /* _ASM_GENERIC_BITOPS_SCHED_H_ */ -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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