Subversion Repositories xilinx_virtex_fp_library

`timescale 1ns / 1ps

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// Company: 

// Engineer: 

// 

// Create Date:    19:08:41 10/21/2013 

// Design Name: 

// Module Name:    effective_op 

// Project Name: 

// Target Devices: 

// Tool versions: 

// Description: 

//

// Dependencies: 

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// Revision: 

// Revision 0.01 - File Created

// Additional Comments: 

//

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module effective_op(    input sign_a,

                                                        input sign_b,

                                                        input sign_c,

                                                        input sub,

                                                        output reg eff_sub);

        wire [2:0] sign_string;

        assign sign_string = {sub, sign_c, sign_a^sign_b};

        always

                @(*)

        begin

                case(sign_string)

                        3'b000: eff_sub = 1'b0;

                        3'b001: eff_sub = 1'b1;

                        3'b010: eff_sub = 1'b1;

                        3'b011: eff_sub = 1'b0;

                        3'b100: eff_sub = 1'b1;

                        3'b101: eff_sub = 1'b0;

                        3'b110: eff_sub = 1'b0;

                        3'b111: eff_sub = 1'b1;

                        default:        eff_sub = 1'b0;

                endcase

        end

endmodule