Subversion Repositories xilinx_virtex_fp_library

`timescale 1ns / 1ps

//////////////////////////////////////////////////////////////////////////////////

// Company:     UPT     

// Engineer:    Constantina-Elena Gavriliu

// 

// Create Date:    18:56:11 10/07/2013 

// Design Name: 

// Module Name:    special_cases

// Project Name: 

// Target Devices: 

// Tool versions: 

// Description: Compute corresponding special cases (exceptions)

//                              //do not take into consideration cases for which the operation generates a NaN or Infinity exception (with corresponding sign) when initial "special cases" are not such exceptions

// Dependencies:        SinglePathFPAdder

//

// Revision: 

// Revision 0.01 - File Created

// Additional Comments: 

//

//////////////////////////////////////////////////////////////////////////////////

module special_cases            #(      parameter size_exception_field = 2'd2,

                                                                        parameter [size_exception_field - 1 : 0] zero                    = 0, //00

                                                                        parameter [size_exception_field - 1 : 0] normal_number= 1, //01

                                                                        parameter [size_exception_field - 1 : 0] infinity                = 2, //10

                                                                        parameter [size_exception_field - 1 : 0] NaN                             = 3) //11

                                                                (       input [size_exception_field - 1 : 0] sp_case_a_number,

                                                                        input [size_exception_field - 1 : 0] sp_case_b_number,

                                                                        output reg [size_exception_field - 1 : 0] sp_case_result_o);

        always

                @(*)

        begin

                case ({sp_case_a_number, sp_case_b_number})

                        {zero, zero}:                                                   sp_case_result_o = zero;

                        {zero, normal_number}:                          sp_case_result_o = normal_number;

                        {zero, infinity}:                                       sp_case_result_o = infinity;

                        {zero, NaN}:                                                    sp_case_result_o = NaN;

                        {normal_number,zero}:                           sp_case_result_o = normal_number;

                        {normal_number,normal_number}:  sp_case_result_o = normal_number;

                        {normal_number,infinity}:                       sp_case_result_o = infinity;

                        {normal_number,NaN}:                                    sp_case_result_o = NaN;

                        {infinity, zero}:                                       sp_case_result_o = infinity;

                        {infinity, normal_number}:              sp_case_result_o = infinity;

                        {infinity, infinity}:                           sp_case_result_o = infinity;

                        {infinity, NaN}:                                                sp_case_result_o = NaN;

                        {NaN, zero}:                                                    sp_case_result_o = NaN;

                        {NaN, normal_number}:                           sp_case_result_o = NaN;

                        {NaN, infinity}:                                                sp_case_result_o = NaN;

                        {NaN, NaN}:                                                     sp_case_result_o = NaN;

                        default:                                                                        sp_case_result_o = zero;

                endcase

        end

endmodule