[mirror_ubuntu-disco-kernel.git] / include / asm-generic / bitops / fls64.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_GENERIC_BITOPS_FLS64_H_
#define _ASM_GENERIC_BITOPS_FLS64_H_

#include <asm/types.h>

/**
 * fls64 - find last set bit in a 64-bit word
 * @x: the word to search
 *
 * This is defined in a similar way as the libc and compiler builtin
 * ffsll, but returns the position of the most significant set bit.
 *
 * fls64(value) returns 0 if value is 0 or the position of the last
 * set bit if value is nonzero. The last (most significant) bit is
 * at position 64.
 */
#if BITS_PER_LONG == 32
static __always_inline int fls64(__u64 x)
{
	__u32 h = x >> 32;
	if (h)
		return fls(h) + 32;
	return fls(x);
}
#elif BITS_PER_LONG == 64
static __always_inline int fls64(__u64 x)
{
	if (x == 0)
		return 0;
	return __fls(x) + 1;
}
#else
#error BITS_PER_LONG not 32 or 64
#endif

#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
2dfc383a AM	2	#ifndef _ASM_GENERIC_BITOPS_FLS64_H_
	3	#define _ASM_GENERIC_BITOPS_FLS64_H_
	4
a54baa14 AM	5	#include <asm/types.h>
a54baa14 AM	6
d57594c2 AH	7	/**
	8	* fls64 - find last set bit in a 64-bit word
	9	* @x: the word to search
	10	*
	11	* This is defined in a similar way as the libc and compiler builtin
	12	* ffsll, but returns the position of the most significant set bit.
	13	*
	14	* fls64(value) returns 0 if value is 0 or the position of the last
	15	* set bit if value is nonzero. The last (most significant) bit is
	16	* at position 64.
	17	*/
	18	#if BITS_PER_LONG == 32
c8399943	19	static __always_inline int fls64(__u64 x)
2dfc383a AM	20	{
	21	__u32 h = x >> 32;
	22	if (h)
	23	return fls(h) + 32;
	24	return fls(x);
	25	}
d57594c2	26	#elif BITS_PER_LONG == 64
c8399943	27	static __always_inline int fls64(__u64 x)
d57594c2 AH	28	{
	29	if (x == 0)
	30	return 0;
	31	return __fls(x) + 1;
	32	}
	33	#else
	34	#error BITS_PER_LONG not 32 or 64
	35	#endif
2dfc383a AM	36
2dfc383a AM	37	#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */