分布式FIR濾波器代碼的一部分 //----------------------- // module description //----------------------- module fir_da( //input din, clock, reset, // dout ); //----------------------- // port declaration //----------------------- input [7:0] din; input clock; input reset; output [7:0] dout; //----------------------------------------------------- // signal declaration //----------------------------------------------------- reg [7:0] din_reg_00_8b; //移位寄存器 reg [7:0] din_reg_01_8b; reg [7:0] din_reg_02_8b; reg [7:0] din_reg_03_8b; reg [7:0] din_reg_04_8b; reg [7:0] din_reg_05_8b; reg [7:0] din_reg_06_8b; function[7:0] lookup_0; input [3:0] din; begin case(din) 4'b0000: lookup_0=16'h0; 4'b0001: lookup_0=16'h0; 4'b0010: lookup_0=16'h1; 4'b0011: lookup_0=16'h1; 4'b0100: lookup_0=16'h3; 4'b0101: lookup_0=16'h3; 4'b0110: lookup_0=16'h4; 4'b0111: lookup_0=16'h4; 4'b1000: lookup_0=16'h4; 4'b1001: lookup_0=16'h4; 4'b1010: lookup_0=16'h5; 4'b1011: lookup_0=16'h5; 4'b1100: lookup_0=16'h7; 4'b1101: lookup_0=16'h7; 4'b1110: lookup_0=16'h8; 4'b1111: lookup_0=16'h8; endcase end endfunction function[7:0] lookup_1; input [3:0] din; begin case(din) 4'b0000: lookup_1=16'h0; 4'b0001: lookup_1=16'h0; 4'b0010: lookup_1=16'h1; 4'b0011: lookup_1=16'h1; 4'b0100: lookup_1=16'h3; 4'b0101: lookup_1=16'h3; 4'b0110: lookup_1=16'h4; 4'b0111: lookup_1=16'h4; 4'b1000: lookup_1=16'h4; 4'b1001: lookup_1=16'h4; 4'b1010: lookup_1=16'h5; 4'b1011: lookup_1=16'h5; 4'b1100: lookup_1=16'h7; 4'b1101: lookup_1=16'h7; 4'b1110: lookup_1=16'h8; 4'b1111: lookup_1=16'h8; endcase end endfunction