Subversion Repositories fixed_point_arithmetic_parameterized

`timescale 1ns / 1ps

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// Company: 

// Engineer: 

// 

// Create Date:    11:21:14 08/24/2011 

// Design Name: 

// Module Name:    q15_mult 

// Project Name: 

// Target Devices: 

// Tool versions: 

// Description: 

//

// Dependencies: 

//

// Revision: 

// Revision 0.01 - File Created

// Additional Comments: 

//

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module qmult(

    input [N-1:0] a,

    input [N-1:0] b,

    output [N-1:0] c

    );

        wire [2*N-1:0] a_ext;

        wire [2*N-1:0] b_ext;

        wire [2*N-1:0] r_ext;

        reg [2*N-1:0] a_mult;

        reg [2*N-1:0] b_mult;

        reg [2*N-1:0] result;

        reg [N-1:0] retVal;

        //Parameterized values

        parameter Q = 15;

        parameter N = 32;

        qtwosComp #(Q,N) comp_a (a[30:0], a_ext);

        qtwosComp #(Q,N) comp_b (b[30:0], b_ext);

        qtwosComp #(Q,N) comp_r (result[N-2+Q:Q], r_ext);

        assign c = retVal;

        always @(a_ext,b_ext)

        begin

                if(a[N-1] == 1)

                        a_mult <= a_ext;

                else

                        a_mult <= a;

                if(b[N-1] == 1)

                        b_mult <= b_ext;

                else

                        b_mult <= b;

        end

        always @(a_mult,b_mult)

        begin

                result <= a_mult * b_mult;

        end;

        always @(result,r_ext)

        begin

                //sign

                if((a[N-1] == 1 && b[N-1] == 0) || (a[N-1] == 0 && b[N-1] == 1)) begin

                        retVal[N-1] <= 1;

                        retVal[N-2:0] <= r_ext[N-2:0];

                end

                else begin

                        retVal[N-1] <= 0;

                        retVal[N-2:0] <= result[N-2+Q:Q];

                end

        end

endmodule