xf_utility.hpp_xfpackpixels-优快云博客

本文链接：https://blog.youkuaiyun.com/jerwey/article/details/103712038

本文详细介绍了使用模板函数实现像素的打包与提取过程。通过xfPackPixels函数将多个低深度像素打包进高宽度字中，以及xfExtractPixels函数从打包的字中提取像素。这两个函数在图像处理和数据压缩中有广泛应用。

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打包pixel 8b—>64b

template <int NPC, int WORDWIDTH, int PIXELDEPTH> //NPC=NPC8,WORDWIDTH=XF_64UW,PIXELDEPTH=XF_8UP
void xfPackPixels(
    XF_PTNAME(PIXELDEPTH) * tmp_buf, //XF_PTNAME(PIXELDEPTH)=ap_uint<8> 
     XF_SNAME(WORDWIDTH) & val, //XF_SNAME(WORDWIDTH)=ap_uint<64>
      uint16_t pos, //0
      int16_t loopIter, //npc =8
       uint16_t& shift //0
       ){
    #pragma HLS INLINE
    ap_uint<8> STEP = XF_PIXELDEPTH(PIXELDEPTH); //XF_PIXELDEPTH(PIXELDEPTH)=8

    for (ap_int<9> i = 0; i < loopIter; i++) {
        #pragma HLS unroll
        XF_PTUNAME(PIXELDEPTH) tmp = tmp_buf[pos]; // XF_PTUNAME(PIXELDEPTH)=ap_uint<8>
        val = val | (((XF_SNAME(WORDWIDTH))tmp) << (shift * STEP));
        pos++;
        shift++;
    }
}
/**
 * Extract Pixels from a packed word into an array from the index pos.
 * The number of pixels to be extracted is determined by the NPC.
 */
template <int NPC, int WORDWIDTH, int PIXELDEPTH>
void xfExtractPixels(XF_PTNAME(PIXELDEPTH) * tmp_buf, XF_SNAME(WORDWIDTH) & val1, int pos) {
    #pragma HLS inline off
    XF_SNAME(WORDWIDTH) v = val1;//XF_SNAME(WORDWIDTH)=ap_uint<64>
    int shift = 0;
    int STEP = XF_PIXELDEPTH(PIXELDEPTH);////XF_PIXELDEPTH(PIXELDEPTH)=8
Extract_pixels_loop:
    for (int i = 0; i < (1 << (XF_BITSHIFT(NPC))); i++) {//XF_BITSHIFT(XF_NPPC8)=3
        #pragma HLS UNROLL
        tmp_buf[pos + i] = v.range(shift + STEP - 1, shift);
        shift = shift + STEP;
    }
}