OVMS3-idf/components/bt/esp_ble_mesh/mesh_common/include/mesh_ffs.h
lly 2983f6edb1 ble_mesh: Spit mesh_util.h into different header files
Split mesh_util.h into mesh_byteorder.h, mesh_compiler.h,
mesh_ffs.h and mesh_util.h based on the classification of
Zephyr, which will make further porting more clear.
2020-05-13 03:40:30 +00:00

61 lines
1.4 KiB
C

/*
* Copyright (c) 2015, Wind River Systems, Inc.
* Copyright (c) 2017, Oticon A/S
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef _BLE_MESH_FFS_H_
#define _BLE_MESH_FFS_H_
#include "mesh_types.h"
#include "mesh_compiler.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
*
* @brief find most significant bit set in a 32-bit word
*
* This routine finds the first bit set starting from the most significant bit
* in the argument passed in and returns the index of that bit. Bits are
* numbered starting at 1 from the least significant bit. A return value of
* zero indicates that the value passed is zero.
*
* @return most significant bit set, 0 if @a op is 0
*/
static ALWAYS_INLINE unsigned int find_msb_set(u32_t op)
{
if (op == 0) {
return 0;
}
return 32 - __builtin_clz(op);
}
/**
*
* @brief find least significant bit set in a 32-bit word
*
* This routine finds the first bit set starting from the least significant bit
* in the argument passed in and returns the index of that bit. Bits are
* numbered starting at 1 from the least significant bit. A return value of
* zero indicates that the value passed is zero.
*
* @return least significant bit set, 0 if @a op is 0
*/
static ALWAYS_INLINE unsigned int find_lsb_set(u32_t op)
{
return __builtin_ffs(op);
}
#ifdef __cplusplus
}
#endif
#endif /* _BLE_MESH_FFS_H_ */