Subversion Repositories fixed_point_arithmetic_parameterized

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// 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: 
//
//////////////////////////////////////////////////////////////////////////////////
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