From: Akinobu Mita Date: Sun, 26 Mar 2006 09:39:12 +0000 (-0800) Subject: [PATCH] bitops: generic sched_find_first_bit() X-Git-Tag: v2.6.17-rc1~518 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=6d29ea23da033f46ac4ab359d46650a7f7474611;p=linux-2.6-omap-h63xx.git [PATCH] bitops: generic sched_find_first_bit() 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/include/asm-generic/bitops/sched.h b/include/asm-generic/bitops/sched.h new file mode 100644 index 00000000000..5ef93a4d009 --- /dev/null +++ b/include/asm-generic/bitops/sched.h @@ -0,0 +1,36 @@ +#ifndef _ASM_GENERIC_BITOPS_SCHED_H_ +#define _ASM_GENERIC_BITOPS_SCHED_H_ + +#include /* unlikely() */ +#include + +/* + * 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_ */