Subversion Repositories xilinx_virtex_fp_library

`timescale 1ns / 1ps

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// Company:     UPT

// Engineer:    Constantina-Elena Gavriliu

// 

// Create Date:    16:09:49 11/04/2013 

// Design Name: 

// Module Name:    rounding 

// Project Name: 

// Target Devices: 

// Tool versions: 

// Description: A ± B rounding

//

// Dependencies: 

//

// Revision: 

// Revision 0.01 - File Created

// Additional Comments: 

//

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module rounding #(      parameter SIZE_MOST_S_MANTISSA = 24,

                                        parameter SIZE_LEAST_S_MANTISSA= 25)

                                (       input [SIZE_MOST_S_MANTISSA - 1 : 0] unrounded_mantissa,

                                        input [SIZE_LEAST_S_MANTISSA- 1 : 0] dummy_bits,

                                        input correction,

                                        output[SIZE_MOST_S_MANTISSA - 1 : 0] rounded_mantissa);

        wire g, sticky, round_dec;

        assign g                = dummy_bits[SIZE_LEAST_S_MANTISSA - 1];

        assign sticky   = (|(dummy_bits[SIZE_LEAST_S_MANTISSA - 3 : 0]));

        assign round    = dummy_bits[SIZE_LEAST_S_MANTISSA - 2];

        assign round_dec                = g & (unrounded_mantissa[0] | sticky | round);

        assign rounded_mantissa = correction? (round_dec? unrounded_mantissa : unrounded_mantissa - 1'b1) : (round_dec? unrounded_mantissa + 1 : unrounded_mantissa);

endmodule