[deliverable/linux.git] / include / asm-generic / bitops / __fls.h

#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_ */
Commit	Line	Data
7d9dff22 AH	1	#ifndef _ASM_GENERIC_BITOPS___FLS_H_
	2	#define _ASM_GENERIC_BITOPS___FLS_H_
	3
	4	#include <asm/types.h>
	5
	6	/**
	7	* __fls - find last (most-significant) set bit in a long word
	8	* @word: the word to search
	9	*
	10	* Undefined if no set bit exists, so code should check against 0 first.
	11	*/
c8399943	12	static __always_inline unsigned long __fls(unsigned long word)
7d9dff22 AH	13	{
	14	int num = BITS_PER_LONG - 1;
	15
	16	#if BITS_PER_LONG == 64
	17	if (!(word & (~0ul << 32))) {
	18	num -= 32;
	19	word <<= 32;
	20	}
	21	#endif
	22	if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
	23	num -= 16;
	24	word <<= 16;
	25	}
	26	if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
	27	num -= 8;
	28	word <<= 8;
	29	}
	30	if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
	31	num -= 4;
	32	word <<= 4;
	33	}
	34	if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
	35	num -= 2;
	36	word <<= 2;
	37	}
	38	if (!(word & (~0ul << (BITS_PER_LONG-1))))
	39	num -= 1;
	40	return num;
	41	}
	42
	43	#endif /* _ASM_GENERIC_BITOPS___FLS_H_ */