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/* ----------------------------------------------------------------------------
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* Copyright (c) Huawei Technologies Co., Ltd. 2013-2019. All rights reserved.
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* Description: BitMap
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* Author: Huawei LiteOS Team
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* Create: 2013-01-01
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice, this list
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* of conditions and the following disclaimer in the documentation and/or other materials
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* provided with the distribution.
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* 3. Neither the name of the copyright holder nor the names of its contributors may be used
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* to endorse or promote products derived from this software without specific prior written
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* permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* --------------------------------------------------------------------------- */
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/*这是一个位图（bitmap）的实现，用于对位图进行设置、清除和获取最高/最低位的操作。
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该位图使用一个32位无符号整数（UINT32）来表示，每一位都代表一个标记
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函数通过位运算来实现对位图的操作，其中包括左移、按位与、按位或、按位取反等操作。*/
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#include "los_bitmap.h"
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#include "los_toolchain.h"
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#ifdef __cplusplus
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#if __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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#endif /* __cplusplus */
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#define OS_BITMAP_MASK 0x1FU
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//LOS_BitmapSet：将指定位置的位设置为1
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VOID LOS_BitmapSet(UINT32 *bitmap, UINT16 pos)
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{
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if (bitmap == NULL) {
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return;
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}
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*bitmap |= 1U << (pos & OS_BITMAP_MASK);
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}
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//LOS_BitmapClr：将指定位置的位清除为0
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VOID LOS_BitmapClr(UINT32 *bitmap, UINT16 pos)
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{
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if (bitmap == NULL) {
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return;
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}
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*bitmap &= ~(1U << (pos & OS_BITMAP_MASK));
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}
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//LOS_HighBitGet：获取位图中最高位（值为1的位置）的索引
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UINT16 LOS_HighBitGet(UINT32 bitmap)
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{
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if (bitmap == 0) {
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return LOS_INVALID_BIT_INDEX;
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}
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return (OS_BITMAP_MASK - CLZ(bitmap));
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}
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//LOS_LowBitGet：获取位图中最低位（值为1的位置）的索引
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UINT16 LOS_LowBitGet(UINT32 bitmap)
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{
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if (bitmap == 0) {
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return LOS_INVALID_BIT_INDEX;
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}
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return CTZ(bitmap);
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}
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#ifdef __cplusplus
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#if __cplusplus
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}
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#endif /* __cplusplus */
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#endif /* __cplusplus */
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