基于MMX指令集的程序设计简介

    if ( nChange > 0 ) //增加象素颜色值
    {
        for ( i = 0; i < nNumberOfPixels; i++ )
        {

            if ( n > 255 )
                n = 255;

            *pDest++ = (BYTE) n;
        }
    }
    else    //减少象素颜色值
    {
        for ( i = 0; i < nNumberOfPixels; i++ )
        {
            n = (int)(*pSource++ - b);

            if ( n < 0 )
                n = 0;
            *pDest++ = (BYTE) n;
        }
    }
  }

  用Visual C++.NET的MMX指令函数实现的改变图象亮度函数：

  void CImg8Operations::ChangeBrightnessC_MMX(