[mirror_ubuntu-eoan-kernel.git] / include / asm-generic / bitops / __ffs.h

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

#include <asm/types.h>

/**
 * __ffs - find first bit in word.
 * @word: The word to search
 *
 * Undefined if no bit exists, so code should check against 0 first.
 */
static __always_inline unsigned long __ffs(unsigned long word)
{
	int num = 0;

#if BITS_PER_LONG == 64
	if ((word & 0xffffffff) == 0) {
		num += 32;
		word >>= 32;
	}
#endif
	if ((word & 0xffff) == 0) {
		num += 16;
		word >>= 16;
	}
	if ((word & 0xff) == 0) {
		num += 8;
		word >>= 8;
	}
	if ((word & 0xf) == 0) {
		num += 4;
		word >>= 4;
	}
	if ((word & 0x3) == 0) {
		num += 2;
		word >>= 2;
	}
	if ((word & 0x1) == 0)
		num += 1;
	return num;
}

#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
c1226a00 AM	2	#ifndef _ASM_GENERIC_BITOPS___FFS_H_
	3	#define _ASM_GENERIC_BITOPS___FFS_H_
	4
	5	#include <asm/types.h>
	6
	7	/**
	8	* __ffs - find first bit in word.
	9	* @word: The word to search
	10	*
	11	* Undefined if no bit exists, so code should check against 0 first.
	12	*/
c8399943	13	static __always_inline unsigned long __ffs(unsigned long word)
c1226a00 AM	14	{
	15	int num = 0;
	16
	17	#if BITS_PER_LONG == 64
	18	if ((word & 0xffffffff) == 0) {
	19	num += 32;
	20	word >>= 32;
	21	}
	22	#endif
	23	if ((word & 0xffff) == 0) {
	24	num += 16;
	25	word >>= 16;
	26	}
	27	if ((word & 0xff) == 0) {
	28	num += 8;
	29	word >>= 8;
	30	}
	31	if ((word & 0xf) == 0) {
	32	num += 4;
	33	word >>= 4;
	34	}
	35	if ((word & 0x3) == 0) {
	36	num += 2;
	37	word >>= 2;
	38	}
	39	if ((word & 0x1) == 0)
	40	num += 1;
	41	return num;
	42	}
	43
	44	#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */