/**
 * Copyright (c) 2026 Huawei Technologies Co., Ltd.
 * This program is free software, you can redistribute it and/or modify it under the terms and conditions of
 * CANN Open Software License Agreement Version 2.0 (the "License").
 * Please refer to the License for details. You may not use this file except in compliance with the License.
 * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE.
 * See LICENSE in the root of the software repository for the full text of the License.
 */

/*!
 * \file reduce_sum_utils.h
 * \brief 提供一些数学工具函数（对齐、除法、取模）
 */

#ifndef REDUCE_SUM_UTILS_H
#define REDUCE_SUM_UTILS_H

#include "mc2_kernel_utils.h"

namespace AscendC {
    
// 向上取整除法：计算a除以b的向上取整结果
__aicore__ inline uint64_t CeilDiv(uint64_t a, uint32_t b)
{
    if (b == 0) {
        return 0;
    }
    return (a + b - 1) / b;
}

// 向下取整除法：计算a除以b的向下取整结果（整数除法）
__aicore__ inline uint64_t FloorDiv(uint64_t a, uint32_t b) {
    if (b == 0) {
        return 0; // 安全处理除零错误
    }
    return a / b; // 整数除法天然向下取整（当a,b为正数时）
}

// 向上对齐：将a向上对齐到b的倍数
__aicore__ inline uint64_t CeilAlign(uint64_t a, uint32_t b)
{
    uint64_t bTemp = static_cast<uint64_t>(b);
    return (bTemp == 0) ? a : CeilDiv(a, bTemp) * bTemp;
}

// 向下对齐：将a向下对齐到b的倍数
__aicore__ inline uint64_t FloorAlign(uint64_t a, uint32_t b)
{
    uint64_t bTemp = static_cast<uint64_t>(b);
    return (bTemp == 0) ? a : FloorDiv(a, bTemp) * bTemp;
}

// 尾块模运算：计算a对b取模，模为0时返回b（用于数据块尾块的计算）
__aicore__ inline uint64_t BlockAlignMod(uint64_t a, uint32_t b)
{
    if (b == 0) {
        return 0;
    }
    
    uint64_t c = a % b;
    return c ? c : b;
}

// 比较取最小值
__aicore__ inline uint64_t MIN(uint64_t x, uint64_t y)
{
    return (x < y) ? x : y;
}
}  // namespace AscendC

#endif // REDUCE_SUM_UTILS_H