Verilog中有符号数计算

该代码实现了一个Sobel边缘检测算法，用于计算图像梯度。通过定义3x3像素矩阵，分别计算水平和垂直方向的梯度（Gx和Gy）。Gx使用[-1,0,1;-2,0,2;-1,0,1]核，Gy使用[-1,-2,-1;0,0,0;1,2,1]核。最终梯度幅度通过G_data=√(Gx²+Gy²)计算得出。代码在时钟上升沿触发，使用寄存器暂存中间结果，通过符号运算完成梯度计算，最终输出10位的梯度幅值数据。

cpp 复制代码

wire            [7:0]           matrix_p11;
wire            [7:0]           matrix_p12;
wire            [7:0]           matrix_p13;
wire            [7:0]           matrix_p21;
wire            [7:0]           matrix_p22;
wire            [7:0]           matrix_p23;
wire            [7:0]           matrix_p31; 
wire            [7:0]           matrix_p32;
wire            [7:0]           matrix_p33;

//----------------------------------------------------------------------
//            [p11,p12,p13]   [-1,0,1]
//  Gx_data = [p21,p22,p23] * [-2,0,2] = (p13+2*p23+p33) - (p11+2*p21+p31)
//            [p31,p32,p33]   [-1,0,1]
//
//            [p11,p12,p13]   [-1,-2,-1]
//  Gy_data = [p21,p22,p23] * [ 0, 0, 0] = (p31+2*p32+p33) - (p11+2*p12+p13)
//            [p31,p32,p33]   [ 1, 2, 1]
//  
//  G_data = sqrt(Gx_data^2 + Gy_data^2)
reg             [ 9:0]          Gx_data_tmp1;
reg             [ 9:0]          Gx_data_tmp2;
reg             [ 9:0]          Gy_data_tmp1;
reg             [ 9:0]          Gy_data_tmp2;
reg signed      [10:0]          Gx_data;
reg signed      [10:0]          Gy_data;
reg signed      [21:0]          Gx_square_data;
reg signed      [21:0]          Gy_square_data;
reg             [20:0]          G_square_data;
wire            [10:0]          G_data;

always @(posedge clk)
begin
    Gx_data_tmp1   <= matrix_p13 + {matrix_p23,1'b0} + matrix_p33;
    Gx_data_tmp2   <= matrix_p11 + {matrix_p21,1'b0} + matrix_p31;
    Gy_data_tmp1   <= matrix_p31 + {matrix_p32,1'b0} + matrix_p33;
    Gy_data_tmp2   <= matrix_p11 + {matrix_p12,1'b0} + matrix_p13;
    Gx_data        <= $signed({1'b0,Gx_data_tmp1}) - $signed({1'b0,Gx_data_tmp2});
    Gy_data        <= $signed({1'b0,Gy_data_tmp1}) - $signed({1'b0,Gy_data_tmp2});
    Gx_square_data <= $signed(Gx_data) * $signed(Gx_data);
    Gy_square_data <= $signed(Gy_data) * $signed(Gy_data);
    G_square_data  <= Gx_square_data[20:0] + Gy_square_data[20:0];
end