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constantin |
`timescale 1ns / 1ps
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//////////////////////////////////////////////////////////////////////////////////
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// Company: UPT
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// Engineer: Constantina-Elena Gavriliu
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//
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// Create Date: 16:09:49 11/04/2013
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// Design Name:
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// Module Name: SinglePathAdderConversion
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// Project Name:
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// Target Devices:
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// Tool versions:
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// Description: A ± B with mapped conversions
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// //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
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//
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// Dependencies: effective_op.v
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// leading_zeros.v
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// rounding.v
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// shifter.v
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// special_cases.v:
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//
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// Revision:
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// Revision 0.01 - File Created
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// Additional Comments:
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//
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//////////////////////////////////////////////////////////////////////////////////
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module SinglePathAdderConversion #( parameter size_mantissa = 24, //calculate the size containing the hiden bit 1.M
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parameter size_exponent = 8,
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parameter size_exception_field = 2,
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parameter size_counter = 5, //log2(size_mantissa) + 1 = 5)
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parameter [size_exception_field - 1 : 0] zero = 0, //00
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parameter [size_exception_field - 1 : 0] normal_number = 1, //01
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parameter [size_exception_field - 1 : 0] infinity = 2, //10
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parameter [size_exception_field - 1 : 0] NaN = 3, //11
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parameter size_integer = 32,
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parameter counter_integer = 6,//log2(size_integer) + 1 = 6)
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parameter [1 : 0] FP_operation = 0, //00
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parameter [1 : 0] FP_to_int = 1, //01
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parameter [1 : 0] int_to_FP = 2, //10
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parameter pipeline = 0,
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parameter pipeline_pos = 0, // 8 bits
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parameter size = size_mantissa + size_exponent + size_exception_field
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)
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( input [1:0] conversion,
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input sub,
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input [size - 1 : 0] a_number_i,
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input [size - 1 : 0] b_number_i,
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output[size - 1 : 0] resulted_number_o);
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parameter double_size_mantissa = size_mantissa + size_mantissa;
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parameter double_size_counter = size_counter + 1;
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parameter max_size = (size_integer > size_mantissa)? size_integer : size_mantissa;
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parameter max_counter = (counter_integer > size_counter)? counter_integer : size_counter;
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parameter size_diff_i_m = (size_integer > size_mantissa)? (size_integer - size_mantissa) : (size_mantissa - size_integer);
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parameter bias = {1'b0,{(size_exponent-1){1'b1}}};
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parameter exp_biased = bias + size_mantissa;
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parameter exponent = exp_biased - 1'b1;
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parameter subtr = max_size -2'd2;
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wire [size_exception_field - 1 : 0] sp_case_a_number, sp_case_b_number;
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wire [size_mantissa - 1 : 0] m_a_number, m_b_number;
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wire [size_exponent - 1 : 0] e_a_number, e_b_number;
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wire s_a_number, s_b_number;
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wire [size_exponent : 0] a_greater_exponent, b_greater_exponent;
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wire [size_exponent - 1 : 0] exp_difference;
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wire [size_exponent : 0] exp_inter;
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wire [size_mantissa - 1 : 0] shifted_m_b, convert_neg_mantissa, mantissa_to_shift;
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wire [size_mantissa - 1 : 0] initial_rounding_bits, final_rounding_bits;
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wire [size_mantissa - 2 : 0] inter_rounding_bits;
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wire eff_op;
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wire [size_mantissa + 2 : 0] adder_mantissa;
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wire [size_mantissa + 1 : 0] unnormalized_mantissa;
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wire [size_exception_field - 1 : 0] sp_case_o, resulted_exception_field;
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wire [size_mantissa - 1 : 0] resulted_mantissa;
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wire [size_exponent - 1 : 0] resulted_exponent;
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wire resulted_sign;
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wire zero_flag;
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wire [size_exponent : 0] subtracter;
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wire [max_size : 0] dummy_bits;
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wire [size_exponent : 0] shift_value_when_positive_exponent, shift_value_when_negative_exponent;
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wire [size_exponent - 1 : 0] shift_value, shft_val;
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wire lsb_shft_bit;
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wire [size_exponent - 1 : 0] max_resulted_e_o;
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wire [size_exponent - 1 : 0] max_unadjusted_exponent, max_adjust_exponent;
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wire [size_exponent - 1 : 0] max_exp_selection;
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wire [size_mantissa - 1 : 0] r_mantissa;
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wire [max_size : 0] max_rounded_mantissa;
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wire [max_counter - 1 : 0] max_lzs;
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wire [max_size - 1 : 0] max_entityINT_FP;
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wire [max_size - 1 : 0] init_entityFP_INT, max_entityFP_INT;
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wire arith_shift;
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wire max_ovf;
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reg intermediar_sign;
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wire [4:0] sign_cases;
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wire do_conversion;
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wire dummy_ovf, correction, negation_cond;
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assign do_conversion = |conversion; //let me know if there is a conversion
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assign e_a_number = a_number_i[size_mantissa + size_exponent - 1 : size_mantissa - 1];
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assign e_b_number = b_number_i[size_mantissa + size_exponent - 1 : size_mantissa - 1];
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assign s_a_number = a_number_i[size - size_exception_field - 1];
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assign s_b_number = b_number_i[size - size_exception_field - 1];
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assign sp_case_a_number = a_number_i[size - 1 : size - size_exception_field];
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assign sp_case_b_number = b_number_i[size - 1 : size - size_exception_field];
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//find the greater exponent
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assign a_greater_exponent = e_a_number - e_b_number;
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assign b_greater_exponent = e_b_number - e_a_number;
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//find the difference between exponents
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assign exp_difference = (a_greater_exponent[size_exponent])? b_greater_exponent[size_exponent - 1 : 0] : a_greater_exponent[size_exponent - 1 : 0];
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assign exp_inter = (b_greater_exponent[size_exponent])? {1'b0, e_a_number} : {1'b0, e_b_number};
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//set shifter always on m_b_number
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assign {m_a_number, m_b_number} = (b_greater_exponent[size_exponent])?
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{{1'b1, a_number_i[size_mantissa - 2 :0]}, {1'b1, b_number_i[size_mantissa - 2 :0]}} :
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{{1'b1, b_number_i[size_mantissa - 2 :0]}, {1'b1, a_number_i[size_mantissa - 2 :0]}};
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assign subtracter = e_a_number - bias;
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assign shift_value_when_positive_exponent = subtr - subtracter[size_exponent-1 : 0];
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assign shift_value_when_negative_exponent = max_size + (~subtracter[size_exponent-1 : 0]);
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assign shift_value = (subtracter[size_exponent])? shift_value_when_negative_exponent[size_exponent - 1 : 0] :
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(shift_value_when_positive_exponent[size_exponent])? (~shift_value_when_positive_exponent[size_exponent - 1 : 0]):
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shift_value_when_positive_exponent[size_exponent - 1 : 0];
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assign shft_val = do_conversion? shift_value : exp_difference;
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assign convert_neg_mantissa = {1'b0, ~a_number_i[size_mantissa-2 : 0]};
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assign mantissa_to_shift = conversion[0]? (s_a_number? convert_neg_mantissa + 1'b1 : {1'b1, a_number_i[size_mantissa-2 : 0]}) : m_b_number;
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assign arith_shift = conversion[0]? s_a_number : 1'b0;
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//shift m_b_number
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shifter #( .INPUT_SIZE(size_mantissa),
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.SHIFT_SIZE(size_exponent),
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.OUTPUT_SIZE(double_size_mantissa),
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.DIRECTION(1'b0), //0=right, 1=left
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.PIPELINE(pipeline),
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.POSITION(pipeline_pos))
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m_b_shifter_instance( .a(mantissa_to_shift),//mantissa
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.arith(arith_shift),//logical shift
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.shft(shft_val),
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.shifted_a({shifted_m_b, initial_rounding_bits}));
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//istantiate effective_operation_component
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effective_op effective_op_instance( .a_sign(s_a_number), .b_sign(s_b_number), .sub(sub), .eff_op(eff_op));
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///compute addition
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assign adder_mantissa = (eff_op)? ({1'b0, m_a_number, 1'b0} - {1'b0, shifted_m_b, initial_rounding_bits[size_mantissa - 1]}) :
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({1'b0, m_a_number, 1'b0} + {1'b0, shifted_m_b, initial_rounding_bits[size_mantissa - 1]});
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//compute unnormalized_mantissa
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assign unnormalized_mantissa = (adder_mantissa[size_mantissa + 2])? ~adder_mantissa[size_mantissa + 1 : 0] : adder_mantissa[size_mantissa + 1 : 0];
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assign inter_rounding_bits = (~(|exp_difference[size_exponent - 1 : 1]))?
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((adder_mantissa[size_mantissa + 2]? ~initial_rounding_bits[size_mantissa - 2 : 0] : initial_rounding_bits[size_mantissa - 2 : 0])) :
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((eff_op)? ((|initial_rounding_bits[size_mantissa - 2 : 0])?~initial_rounding_bits[size_mantissa - 2 : 0] : initial_rounding_bits[size_mantissa - 2 : 0]) : initial_rounding_bits[size_mantissa - 2 : 0]);
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assign max_entityINT_FP = do_conversion? (a_number_i[size_integer-1]? (~a_number_i[max_size-1 : 0]) : a_number_i[max_size-1 : 0]) :
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{{(max_size-size_mantissa-2){1'b0}}, unnormalized_mantissa[size_mantissa + 1 : 0]};
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assign lsb_shft_bit = (do_conversion)? (conversion[0]? s_a_number : a_number_i[size_integer-1]) : inter_rounding_bits[0];
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//compute leading_zeros over unnormalized mantissa
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leading_zeros #( .SIZE_INT(max_size), .SIZE_COUNTER(max_counter), .PIPELINE(pipeline))
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leading_zeros_instance (.a(max_entityINT_FP),
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.ovf(1'b0),
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.lz(max_lzs));
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assign final_rounding_bits = conversion[1]? {size_mantissa{a_number_i[size_integer-1]}} : {inter_rounding_bits, inter_rounding_bits[0]};
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//compute shifting over unnormalized_mantissa
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shifter #( .INPUT_SIZE(max_size + size_mantissa),
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.SHIFT_SIZE(max_counter),
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.OUTPUT_SIZE(max_size + size_mantissa + 1),
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.DIRECTION(1'b1), //0=right, 1=left
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.PIPELINE(pipeline),
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.POSITION(pipeline_pos))
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shifter_instance( .a({max_entityINT_FP, final_rounding_bits}),//mantissa
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.arith(lsb_shft_bit),//logical shift
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.shft(max_lzs),
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.shifted_a({r_mantissa, dummy_bits}));
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wire [max_size - 1 : 0] entity_to_shift;
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wire [max_size : 0] dummy_entity;
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assign entity_to_shift = conversion[0]? {shifted_m_b, initial_rounding_bits[size_mantissa-1 : size_mantissa - size_diff_i_m + 1]} : {{size_diff_i_m{1'b0}},r_mantissa};
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assign dummy_entity = conversion[0]? {initial_rounding_bits[size_mantissa - size_diff_i_m : 0], {(max_size + size_diff_i_m - size_mantissa){1'b0}}} :
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((conversion[1] & (&dummy_bits[max_size-1:0]) & (~dummy_bits[max_size]))? (a_number_i[size_integer-1]? ~dummy_bits : dummy_bits) : dummy_bits);
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assign correction = ~(|exp_difference[size_exponent - 1 : 1])? 1'b0 :
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(eff_op? ((|initial_rounding_bits[size_mantissa - 2 : 0])?
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((adder_mantissa[0] | ((~adder_mantissa[0]) & (~adder_mantissa[size_mantissa]) & (~initial_rounding_bits[size_mantissa - 1])
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& (~(&final_rounding_bits[size_mantissa-2 : 0]))))? 1'b1 : 1'b0) : 1'b0) : 1'b0);
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//instantiate rounding_component
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rounding #( .SIZE_MOST_S_MANTISSA(max_size + 1),
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.SIZE_LEAST_S_MANTISSA(max_size + 1))
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rounding_instance( .unrounded_mantissa({1'b0,entity_to_shift}),
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.dummy_bits(dummy_entity),
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.correction(correction),
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.rounded_mantissa(max_rounded_mantissa));
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assign max_entityFP_INT = {s_a_number, max_rounded_mantissa[max_size - 2 : 0]};
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assign max_exp_selection = do_conversion? exponent : exp_inter-1'b1;
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assign max_adjust_exponent = max_exp_selection - max_lzs;
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assign max_unadjusted_exponent = max_adjust_exponent + size_diff_i_m;
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assign max_resulted_e_o = (do_conversion & ~(|max_entityINT_FP))? bias : max_unadjusted_exponent + max_rounded_mantissa[size_mantissa];
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assign resulted_exponent = conversion[0]? max_entityFP_INT[size_mantissa+size_exponent-2 : size_mantissa-1] : max_resulted_e_o;
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assign resulted_mantissa = conversion[0]? max_entityFP_INT[size_mantissa-1 : 0] :
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(max_rounded_mantissa[size_mantissa])? (max_rounded_mantissa[size_mantissa : 1]) :
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(max_rounded_mantissa[size_mantissa-1 : 0]);
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//compute exception_field
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special_cases #( .size_exception_field(size_exception_field),
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.zero(zero),
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.normal_number(normal_number),
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.infinity(infinity),
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.NaN(NaN))
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special_cases_instance( .sp_case_a_number(sp_case_a_number),
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.sp_case_b_number(sp_case_b_number),
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.sp_case_result_o(sp_case_o));
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//compute special case
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19 |
constantin |
assign resulted_exception_field = conversion[0]? 2'd0:
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conversion[1]? normal_number : sp_case_o;
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18 |
constantin |
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//set zero_flag in case of equal numbers
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assign zero_flag = ~((|{resulted_mantissa,sp_case_o[1]}) & (|sp_case_o));
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assign sign_cases = {eff_op, s_a_number, s_b_number, a_greater_exponent[size_exponent], b_greater_exponent[size_exponent]};
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always
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@(*)
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begin
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case (sign_cases)
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5'b00000: intermediar_sign = 1'b0;
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5'b00001: intermediar_sign = 1'b0;
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5'b00010: intermediar_sign = 1'b0;
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5'b10000: intermediar_sign = ~adder_mantissa[size_mantissa+1];
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5'b10001: intermediar_sign = 1'b0;
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5'b10010: intermediar_sign = 1'b1;
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5'b10100: intermediar_sign = ~adder_mantissa[size_mantissa+1];
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5'b10101: intermediar_sign = 1'b0;
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5'b10110: intermediar_sign = 1'b1;
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5'b00100: intermediar_sign = 1'b0;
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5'b00101: intermediar_sign = 1'b0;
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5'b00110: intermediar_sign = 1'b0;
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5'b11000: intermediar_sign = adder_mantissa[size_mantissa+1];
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5'b11001: intermediar_sign = 1'b1;
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5'b11010: intermediar_sign = 1'b0;
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5'b01000: intermediar_sign = 1'b1;
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5'b01001: intermediar_sign = 1'b1;
|
275 |
|
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5'b01010: intermediar_sign = 1'b1;
|
276 |
|
|
|
277 |
|
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5'b01100: intermediar_sign = 1'b1;
|
278 |
|
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5'b01101: intermediar_sign = 1'b1;
|
279 |
|
|
5'b01110: intermediar_sign = 1'b1;
|
280 |
|
|
|
281 |
|
|
5'b11100: intermediar_sign = adder_mantissa[size_mantissa+1];
|
282 |
|
|
5'b11101: intermediar_sign = 1'b1;
|
283 |
|
|
5'b11110: intermediar_sign = 1'b0;
|
284 |
|
|
|
285 |
|
|
default: intermediar_sign = 1'b1;
|
286 |
|
|
endcase
|
287 |
|
|
end
|
288 |
|
|
|
289 |
19 |
constantin |
assign resulted_sign = conversion[0]? 1'b0 :
|
290 |
|
|
conversion[1]? a_number_i[size_integer-1] : intermediar_sign;
|
291 |
18 |
constantin |
|
292 |
|
|
assign resulted_number_o = do_conversion? {resulted_exception_field, resulted_sign, resulted_exponent, resulted_mantissa[size_mantissa - 2 : 0]} :
|
293 |
|
|
(zero_flag | (~(|resulted_exception_field)))? {size{1'b0}} :
|
294 |
|
|
(&(resulted_exception_field))? {resulted_exception_field, resulted_sign,{(size-1-size_exception_field){1'b0}}} :
|
295 |
|
|
(resulted_exception_field[1])? {resulted_exception_field, {(size-size_exception_field){1'b0}}} :
|
296 |
|
|
(!sp_case_a_number)? {b_number_i[size-1 : size-size_exception_field], resulted_sign, b_number_i[size-1-size_exception_field-1 : 0]} :
|
297 |
|
|
(!sp_case_b_number)? {a_number_i[size-1 : size-size_exception_field], resulted_sign, a_number_i[size-1-size_exception_field-1 : 0]} :
|
298 |
|
|
{resulted_exception_field, resulted_sign, resulted_exponent, resulted_mantissa[size_mantissa - 2 : 0]};
|
299 |
|
|
|
300 |
|
|
endmodule
|