ffs.h

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/*
 * Copyright (c) 2015, Wind River Systems, Inc.
 * Copyright (c) 2017, Oticon A/S
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef ZEPHYR_INCLUDE_ARCH_COMMON_FFS_H_
#define ZEPHYR_INCLUDE_ARCH_COMMON_FFS_H_
 
#ifndef _ASMLANGUAGE
 
#include <zephyr/types.h>
#include <zephyr/toolchain.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
static ALWAYS_INLINE unsigned int find_msb_set(uint32_t op)
{
        if (op == 0) {
                return 0;
        }
 
        return 32 - __builtin_clz(op);
}
 
 
static ALWAYS_INLINE unsigned int find_lsb_set(uint32_t op)
{
#ifdef CONFIG_TOOLCHAIN_HAS_BUILTIN_FFS
        return __builtin_ffs(op);
 
#else
        /*
         * Toolchain does not have __builtin_ffs(). Leverage find_lsb_set()
         * by first clearing all but the lowest set bit.
         */
 
        op = op ^ (op & (op - 1));
 
        return find_msb_set(op);
#endif /* CONFIG_TOOLCHAIN_HAS_BUILTIN_FFS */
}
 
#ifdef __cplusplus
}
#endif
 
#endif /* _ASMLANGUAGE */
 
#endif /* ZEPHYR_INCLUDE_ARCH_COMMON_FFS_H_ */