Subversion Repositories xilinx_virtex_fp_library

`timescale 1ns / 1ps

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// Company: 

// Engineer: 

// 

// Create Date:    00:31:57 11/19/2013 

// Design Name: 

// Module Name:    FarPath 

// Project Name: 

// Target Devices: 

// Tool versions: 

// Description: A ± B when |Ea-Eb| >= 2

//

// Dependencies: 

//

// Revision: 

// Revision 0.01 - File Created

// Additional Comments: 

//

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module FarPath  #(      parameter size_in_mantissa                      = 24, //1.M

                                                parameter size_out_mantissa             = 24,

                                                parameter size_exponent                         = 8,

                                                parameter pipeline                                      = 0,

                                                parameter pipeline_pos                          = 0,     // 8 bits

                                                parameter size_counter                          = 5,    //log2(size_mantissa) + 1 = 5)

                                                parameter double_size_counter           = size_counter + 1,

                                                parameter double_size_mantissa  = size_in_mantissa + size_in_mantissa)

                                        (       input eff_op,

                                                input [size_in_mantissa-1 :0] m_a_number,

                                                input [size_in_mantissa-1 :0] m_b_number,

                                                input [size_exponent - 1 : 0] e_a_number,

                                                input [size_exponent - 1 : 0] e_b_number,

                                                output[size_out_mantissa-1:0] resulted_m_o,

                                                output[size_exponent - 1 : 0] resulted_e_o);

        wire [double_size_mantissa:0] unnormalized_mantissa;

        wire [7:0] adjust_mantissa;

        wire [double_size_mantissa:0] normalized_mantissa;

        wire dummy_bit;

        //compute unnormalized_mantissa

        assign unnormalized_mantissa = (eff_op)? ((m_a_number > m_b_number)? (m_a_number - m_b_number) : (m_b_number - m_a_number)) :

                                                                                                                        m_a_number + m_b_number;

        assign adjust_mantissa = unnormalized_mantissa[double_size_mantissa]? 8'd0 :

                                                                                unnormalized_mantissa[double_size_mantissa-1]? 2'd1 : 8'd2;

        //compute shifting over unnormalized_mantissa

        shifter #(      .INPUT_SIZE(double_size_mantissa+1),

                                        .SHIFT_SIZE(size_exponent),

                                        .OUTPUT_SIZE(double_size_mantissa+2),

                                        .DIRECTION(1'b1),

                                        .PIPELINE(pipeline),

                                        .POSITION(pipeline_pos))

                unnormalized_no_shifter_instance(.a(unnormalized_mantissa),

                                                                                                        .arith(1'b0),

                                                                                                        .shft(adjust_mantissa),

                                                                                                        .shifted_a({normalized_mantissa, dummy_bit}));

        //instantiate rounding_component

        rounding #(     .SIZE_MOST_S_MANTISSA(size_out_mantissa),

                                        .SIZE_LEAST_S_MANTISSA(size_out_mantissa + 2'd1))

                rounding_instance(      .unrounded_mantissa(normalized_mantissa[double_size_mantissa : double_size_mantissa - size_out_mantissa + 1]),

                                                                        .dummy_bits(normalized_mantissa[double_size_mantissa - size_out_mantissa: 0]),

                                                                        .rounded_mantissa(resulted_m_o));

        assign resulted_e_o = (e_a_number > e_b_number)? (e_a_number + 1 - adjust_mantissa):(e_b_number + 1 - adjust_mantissa);

endmodule