__fls.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * \file    asm-generic/bitops/__fls.h
 * \brief   This file is originally from the Linux Kernel source-code and has
 *          been very slightly modified to integrate to QNX RTOS.
 *
 * Please also check the "SPDX-License-Identifier" documentation from the Linux
 * Kernel source code repository: github.com/torvalds/linux.git for further
 * details.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef _ASM_GENERIC_BITOPS___FLS_H_
#define _ASM_GENERIC_BITOPS___FLS_H_

#ifdef __QNX__
#include <linux/types.h>
#else
#include <asm/types.h>
#endif

/**
 * generic___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 __attribute_const__ unsigned int generic___fls(unsigned long word)
{
	unsigned 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;
}

#ifndef __HAVE_ARCH___FLS
#define __fls(word) generic___fls(word)
#endif

#endif /* _ASM_GENERIC_BITOPS___FLS_H_ */