hls::LineBuffer 源码解析

hls::LineBuffer 

以下是LineBuffer的类定义，可以看到初始化，需要的数据包括行、列、类型名字（如char）和转置（默认行列） 本质上是一个二维数组

/* Template class of Line Buffer */
template<int ROWS, int COLS, typename T, int RESHAPE=0>
class LineBuffer;

template<int ROWS, int COLS, typename T>
class LineBuffer<ROWS, COLS, T, 0> {
public:
    LineBuffer() {
#pragma HLS array_partition variable=val dim=1 complete	 //对这样一个二维数组，HLS采取的优化是将每行数据放在寄存器当中
#pragma HLS dependence variable=val inter false
#pragma HLS dependence variable=val intra false
    };
    /* LineBuffer main APIs */
    void shift_pixels_up(int col);
    void shift_pixels_down(int col);
    void insert_bottom_row(T value, int col);
    void insert_top_row(T value, int col);
    void get_col(T value[ROWS], int col);
    T& getval(int row, int col);
    T& operator ()(int row, int col);

    /* Back compatible APIs */
    void shift_up(int col);
    void shift_down(int col);
    void insert_bottom(T value, int col);
    void insert_top(T value, int col);
    //T& getval(int row, int col);
    //T& operator ()(int row, int col);

    T val[ROWS][COLS];
#ifdef _HLSCLIB_DEBUG_
    void restore_val();
    void linebuffer_print(int col);
    T val_t[ROWS][COLS];
#endif
};

lineBuf.shift_pixels_up(j);
lineBuf.insert_bottom_row(pix,j);

lineBuf.shift_pixels_up(int col);

该函数实现的是将linebuf某一列的数组向上移动1位

template<int ROWS, int COLS, typename T> void LineBuffer<ROWS, COLS, T, 1>::shift_pixels_up(int col) {
#pragma HLS inline
    assert(col >= 0 && col < COLS);

#ifdef _HLSCLIB_DEBUG_
    std::cout << "LineBuffer Elements in col=" << col << ":";
    linebuffer_print(col);
    restore_val();
#endif

    HLS_SIZE_T i;										//核心代码
    for(i = 0; i < ROWS-1; i++) {
#pragma HLS unroll										//#pragma HLS unroll 循环并行化
        val[i][col] = val[i+1][col];								
    }

#ifdef _HLSCLIB_DEBUG_
    std::cout << "===  After " << __FUNCTION__ << ":  ===\n\n";
    std::cout << "LineBuffer Elements Update in col=" << col << ":";
    linebuffer_print(col);
    HLS_SIZE_T j;
    for(i = 0; i < ROWS; i++) {
        for(j = 0; j < COLS; j++) {
            if(j==col)
                if(i==ROWS-1)
                    assert(val_t[i][j] == val[i][j] && "*** window shift_pixels_up mismatch! ***");
                else
                    assert(val_t[i+1][j] == val[i][j] && "*** window shift_pixels_up mismatch! ***");
            else
                assert(val_t[i][j] == val[i][j] && "*** window shift_pixels_up mismatch! ***");
        }
    }
#endif

}

lineBuf.insert_bottom_row(value,col);

该函数是将某一列的最后一行的数据赋值成新数据，通常与shift_pixels_up连用

/* LineBuffer insert bottom row 
 * Inserts a new value in bottom row= ROWS-1 of the linebuffer
 */
template<int ROWS, int COLS, typename T> void LineBuffer<ROWS, COLS, T, 1>::insert_bottom_row(T value, int col) {
#pragma HLS inline
    assert(col >= 0 && col < COLS);

#ifdef _HLSCLIB_DEBUG_
    std::cout << "LineBuffer Elements in col=" << col << ":";
    linebuffer_print(col);
    restore_val();
#endif

    val[ROWS-1][col] = value;			//核心代码

#ifdef _HLSCLIB_DEBUG_
    std::cout << "===  After " << __FUNCTION__ << ":  ===\n\n";
    std::cout << "LineBuffer Elements Update in col=" << col << ":";
    linebuffer_print(col);
    HLS_SIZE_T i, j;
    for(i = 0; i < ROWS; i++) {
        for(j = 0; j < COLS; j++) {
            if(j==col && i==ROWS-1)
                assert(val[i][j] == value && "*** window insert_bottom_row mismatch! ***");
            else
                assert(val_t[i][j] == val[i][j] && "*** window insert_bottom_row mismatch! ***");
        }
    }
#endif

}