Subversion Repositories xilinx_virtex_fp_library

`timescale 1ns / 1ps

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

// Company: 

// Engineer: 

// 

// Create Date:    17:53:05 10/15/2013 

// Design Name: 

// Module Name:    Multiply_Accumulate 

// Project Name: 

// Target Devices: 

// Tool versions: 

// Description: C ± A*B

//

// Dependencies: 

//

// Revision: 

// Revision 0.01 - File Created

// Additional Comments: 

//

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

module Multiply_Accumulate #(   parameter size_exponent = 8,    //exponent bits

                                                                                parameter size_mantissa = 24,   //mantissa bits

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

                                                                                parameter size_exception_field = 2,     // zero/normal numbers/infinity/NaN

                                                                                parameter zero                          = 00, //00

                                                                                parameter normal_number = 01, //01

                                                                                parameter infinity              = 10, //10

                                                                                parameter NaN                           = 11, //11

                                                                                parameter pipeline              = 0,

                                                                                parameter pipeline_pos  = 0,  //8 bits

                                                                                parameter size = size_exponent + size_mantissa + size_exception_field,

                                                                                parameter size_mul_mantissa = size_mantissa + size_mantissa,

                                                                                parameter size_mul_counter = size_counter + 1)

                                                                        (       input clk,

                                                                                input rst,

                                                                                input [size - 1:0] a_number_i,

                                                                                input [size - 1:0] b_number_i,

                                                                                input [size - 1:0] c_number_i,

                                                                                input sub,

                                                                                output[size - 1:0] resulting_number_o);

        wire [size_mantissa - 1 : 0] m_a_number, m_b_number, m_c_number;

        wire [size_exponent - 1 : 0] e_a_number, e_b_number, e_c_number;

        wire s_a_number, s_b_number, s_c_number;

        wire [size_exception_field - 1 : 0] sp_case_a_number, sp_case_b_number, sp_case_c_number;

        //---------------------------------------------------------------------------------------

        wire [size_mul_mantissa-1:0] mul_mantissa, c_mantissa;

        wire [size_mul_mantissa  :0] acc_resulting_number;

        wire [size_mul_mantissa  :0] ab_shifted_mul_mantissa, c_shifted_mantissa;

        wire [size_exponent : 0] exp_ab;

        wire [size_exponent-1:0] modify_exp_ab, modify_exp_c;

        wire [size_mul_counter-1: 0] lz_mul;

        wire sign_res;

        wire eff_sub;

        wire ovf;

        wire comp_exp;

        wire [size_mul_mantissa+1:0] normalized_mantissa;

        wire [size_mantissa - 1 : 0] rounded_mantissa;

        wire [size_exponent  :0] unnormalized_exp;

        wire [size_mantissa-2:0] final_mantissa;

        wire [size_exponent-1:0] final_exponent;

        wire [size_exception_field - 1 : 0] sp_case_result_o;

        assign m_a_number               = {1'b1, a_number_i[size_mantissa - 2 :0]};

        assign m_b_number                       = {1'b1, b_number_i[size_mantissa - 2 :0]};

        assign m_c_number                       = {1'b1, c_number_i[size_mantissa - 2 :0]};

        assign e_a_number                       = a_number_i[size_mantissa + size_exponent - 1 : size_mantissa - 1];

        assign e_b_number                       = b_number_i[size_mantissa + size_exponent - 1 : size_mantissa - 1];

        assign e_c_number                       = c_number_i[size_mantissa + size_exponent - 1 : size_mantissa - 1];

        assign s_a_number                       = a_number_i[size - size_exception_field - 1];

        assign s_b_number                       = b_number_i[size - size_exception_field - 1];

        assign s_c_number                       = c_number_i[size - size_exception_field - 1];

        assign sp_case_a_number = a_number_i[size - 1 : size - size_exception_field];

        assign sp_case_b_number = b_number_i[size - 1 : size - size_exception_field];

        assign sp_case_c_number = c_number_i[size - 1 : size - size_exception_field];

        //instantiate multiply component

        multiply #(     .size_mantissa(size_mantissa),

                                        .size_counter(size_counter),

                                        .size_mul_mantissa(size_mul_mantissa))

                multiply_instance (     .a_mantissa_i(m_a_number),

                                                                        .b_mantissa_i(m_b_number),

                                                                        .mul_mantissa(mul_mantissa));

        assign c_mantissa = {1'b0,m_c_number, {(size_mantissa-1'b1){1'b0}}};

        assign exp_ab = e_a_number + e_b_number - ({1'b1,{(size_exponent-1'b1){1'b0}}} - 1'b1);

        assign {modify_exp_ab, modify_exp_c, unnormalized_exp} = (exp_ab >= e_c_number)? {8'd0,(exp_ab - e_c_number), exp_ab} : {(e_c_number - exp_ab), 8'd0, {1'b0,e_c_number}};

        //instantiate shifter component for mul_mantissa shift, mul_mantissa <=> ab_mantissa

        shifter #(      .INPUT_SIZE(size_mul_mantissa),

                                        .SHIFT_SIZE(size_exponent),

                                        .OUTPUT_SIZE(size_mul_mantissa + 1'b1),

                                        .DIRECTION(1'b0),

                                        .PIPELINE(pipeline),

                                        .POSITION(pipeline_pos))

                shifter_ab_instance(    .a(mul_mantissa),

                                                                        .arith(1'b0),

                                                                        .shft(modify_exp_ab),

                                                                        .shifted_a(ab_shifted_mul_mantissa));

        //instantiate shifter component for c_mantissa shift

        shifter #(      .INPUT_SIZE(size_mul_mantissa),

                                        .SHIFT_SIZE(size_exponent),

                                        .OUTPUT_SIZE(size_mul_mantissa + 1'b1),

                                        .DIRECTION(1'b0),

                                        .PIPELINE(pipeline),

                                        .POSITION(pipeline_pos))

                shifter_c_instance(     .a(c_mantissa),

                                                                        .arith(1'b0),

                                                                        .shft(modify_exp_c),

                                                                        .shifted_a(c_shifted_mantissa));

        //instantiate effective_op component

        effective_op effective_op_instance(     .sign_a(s_a_number),

                                                                                                        .sign_b(s_b_number),

                                                                                                        .sign_c(s_c_number),

                                                                                                        .sub(sub),

                                                                                                        .eff_sub(eff_sub));

        //instantiate accumulate component

        accumulate #(   .size_mantissa(size_mantissa),

                                                .size_counter(size_counter),

                                                .size_mul_mantissa(size_mul_mantissa))

                accumulate_instance (   .ab_number_i(ab_shifted_mul_mantissa[size_mul_mantissa:1]),

                                                                                .c_number_i(c_shifted_mantissa[size_mul_mantissa:1]),

                                                                                .sub(eff_sub),

                                                                                .ovf(ovf),

                                                                                .acc_resulting_number_o(acc_resulting_number));

        //instantiate leading_zeros component

        leading_zeros #(        .SIZE_INT(size_mul_mantissa + 1'b1),

                                                        .SIZE_COUNTER(size_mul_counter),

                                                        .PIPELINE(pipeline))

                leading_zeros_instance( .a(acc_resulting_number),

                                                                                .ovf(ovf),

                                                                                .lz(lz_mul));

        //instantiate shifter component

        shifter #(      .INPUT_SIZE(size_mul_mantissa + 1'b1),

                                        .SHIFT_SIZE(size_mul_counter),

                                        .OUTPUT_SIZE(size_mul_mantissa + 2'd2),

                                        .DIRECTION(1'b1),

                                        .PIPELINE(pipeline),

                                        .POSITION(pipeline_pos))

                shifter_instance(       .a(acc_resulting_number),

                                                                .arith(1'b0),

                                                                .shft(lz_mul),

                                                                .shifted_a(normalized_mantissa));

        //instantiate rounding component

        rounding #(     .SIZE_MOST_S_MANTISSA(size_mantissa),

               .SIZE_LEAST_S_MANTISSA(size_mul_mantissa-size_mantissa+2))

                rounding_instance       (       .unrounded_mantissa(normalized_mantissa[size_mul_mantissa+1 : size_mul_mantissa+2-size_mantissa]),

                                                                        .dummy_bits(normalized_mantissa[size_mul_mantissa+1-size_mantissa : 0]),

                                                                        .rounded_mantissa(rounded_mantissa));

        //instantiate special_cases_mul_acc component

        special_cases_mul_acc   #(      .size_exception_field(size_exception_field),

                                                                                .zero(zero),

                                                                                .normal_number(normal_number),

                                                                                .infinity(infinity),

                                                                                .NaN(NaN))

                special_cases_mul_acc_instance  (       .sp_case_a_number(sp_case_a_number),

                                                                                                                .sp_case_b_number(sp_case_b_number),

                                                                                                                .sp_case_c_number(sp_case_c_number),

                                                                                                                .sp_case_result_o(sp_case_result_o));

        //compute resulted_sign

        assign sign_res = (eff_sub)? ((c_shifted_mantissa > ab_shifted_mul_mantissa)? s_c_number : ~s_c_number) : s_c_number;

        assign final_exponent = unnormalized_exp - lz_mul + 2'd2;

        assign final_mantissa = rounded_mantissa[size_mantissa-2 : 0];

        assign resulting_number_o = {sp_case_result_o, sign_res, final_exponent, final_mantissa};

endmodule