正在阅读：基于MMX指令集的程序设计简介基于MMX指令集的程序设计简介

    _mm_empty();                            // 执行MMX指令：emms

    __m64 nChange64 = Get_m64(c);

    if ( nChange > 0 )
    {
        for ( i = 0; i < nNumberOfLoops; i++ )
        {
       tmp = _mm_adds_pu8(*pIn, nChange64); //  饱和模式下的无符号加法
                                                 // 对每一个字节执行操作：tmp = *pIn + nChange64

            *pOut = tmp;

            pIn++;                               // 取下面8个象素
            pOut++;
        }
    }
    else
    {
        for ( i = 0; i < nNumberOfLoops; i++ )
        {
         tmp = _mm_subs_pu8(*pIn, nChange64); //  饱和模式下的无符号减法
                                                 // 对每一个字节执行操作：tmp = *pIn - nChange64

            *pOut = tmp;

            pIn++;                                      //取下面8个象素