Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6d29ea23 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
Browse files

[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: default avatarAkinobu Mita <mita@miraclelinux.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c7f612cd

include/asm-generic/bitops/sched.h

0 → 100644
+36 −0
Original line number Diff line number Diff line 
#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_ */