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[/] [xilinx_virtex_fp_library/] [trunk/] [DualPathFPAdderMappedConversions/] [DualPathAdderConversion.v] - Blame information for rev 19

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Line No. Rev Author Line
1 11 constantin
`timescale 1ns / 1ps
2
//////////////////////////////////////////////////////////////////////////////////
3 19 constantin
// Company:     UPT
4
// Engineer:    Constantina-Elena Gavriliu
5 11 constantin
// 
6
// Create Date:    00:31:28 12/19/2013 
7
// Design Name: 
8
// Module Name:    DualPathAdderConversion
9
// Project Name: 
10
// Target Devices: 
11
// Tool versions: 
12
// Description: A  B with mapped conversions 
13 19 constantin
//                              //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
14 11 constantin
//
15 19 constantin
// Dependencies:        effective_op.v
16
//                                      leading_zeros.v
17
//                                      shifter.v
18
//                                      rounding.v
19
//                                      special_cases.v
20 11 constantin
//
21
// Revision: 
22
// Revision 0.01 - File Created
23
// Additional Comments: 
24
//
25
//////////////////////////////////////////////////////////////////////////////////
26
module DualPathAdderConversion #(       parameter size_mantissa                         = 24, //1.M
27
                                                                        parameter size_exponent                         = 8,
28
                                                                        parameter size_exception_field          = 2,
29
                                                                        parameter size_counter                          = 5,//log2(size_mantissa) + 1 = 5)
30
                                                                        parameter [size_exception_field - 1 : 0] zero                    = 0, //00
31
                                                                        parameter [size_exception_field - 1 : 0] normal_number   = 1, //01
32
                                                                        parameter [size_exception_field - 1 : 0] infinity                = 2, //10
33
                                                                        parameter [size_exception_field - 1 : 0] NaN                     = 3, //11
34
                                                                        parameter size_integer                  = 32,
35
                                                                        parameter counter_integer               = 6,//log2(size_integer) + 1 = 6)
36
                                                                        parameter [1 : 0] FP_operation   = 0, //00 
37
                                                                        parameter [1 : 0] FP_to_int              = 1, //01 - mapped on FarPath
38
                                                                        parameter [1 : 0] int_to_FP              = 2, //10 - mapped on ClosePath
39
 
40
                                                                        parameter pipeline                                      = 0,
41
                                                                        parameter pipeline_pos                          = 0,     // 8 bits
42
                                                                        parameter size                                          = size_mantissa + size_exponent + size_exception_field
43
                                                                        )
44
                                                                        (       input [1:0] conversion,
45
                                                                                input sub,
46
                                                                                input [size - 1 : 0] a_number_i,
47
                                                                                input [size - 1 : 0] b_number_i,
48
                                                                                output[size - 1 : 0] resulted_number_o);
49
 
50
        parameter double_size_mantissa  = size_mantissa + size_mantissa;
51
        parameter double_size_counter   = size_counter + 1;
52
        parameter max_size                              = (size_integer > size_mantissa)? size_integer : size_mantissa;
53
        parameter max_counter                   = (counter_integer > size_counter)? counter_integer : size_counter;
54
        parameter size_diff_i_m                 = (size_integer > size_mantissa)? (size_integer - size_mantissa) : (size_mantissa - size_integer);
55
        parameter bias                                  = {1'b0,{(size_exponent-1){1'b1}}};
56
        parameter exp_biasedCP                  = bias + size_mantissa;
57
        parameter exponentCP                    = exp_biasedCP - 1'b1;
58
 
59
        wire [size_exception_field - 1 : 0] sp_case_a_number, sp_case_b_number;
60
        wire [size_mantissa - 1 : 0] m_a_number, m_b_number;
61
        wire [size_exponent - 1 : 0] e_a_number, e_b_number;
62
        wire s_a_number, s_b_number;
63
 
64
        wire [size_exponent     : 0] a_greater_exponent, b_greater_exponent;
65
 
66
        wire [size_exponent - 1 : 0] exp_difference;
67
        wire [size_exponent     : 0] exp_inter;
68
        wire eff_op;
69
 
70 19 constantin
        wire [size_exception_field - 1 : 0] set_b_sp_case, resulted_exception_field;
71 11 constantin
        wire resulted_sign;
72
        wire swap;
73
 
74
        wire zero_flag;
75
 
76
        wire [max_size - 1 : 0] max_entityFP;
77
        wire [size_exponent - 1 : 0] resulted_e_oFP;
78
        wire [size_exponent - 1 : 0] adjust_mantissaFP;
79
        wire [size_exponent - 1 : 0] unadjusted_exponentFP;
80
        wire [size_mantissa - 1 : 0] mantissa_to_shiftFP, shifted_m_bFP, convert_neg_mantissaFP;
81 19 constantin
        wire [size_mantissa + 2 : 0] adder_mantissaFP;
82 11 constantin
        wire [size_mantissa - 1 : 0] resulted_inter_m_oFP, resulted_m_oFP;
83 19 constantin
        wire [size_mantissa - 1 : 0] initial_rounding_bitsFP;
84
        wire [size_mantissa - 2 : 0] inter_rounding_bitsFP;
85 11 constantin
        wire [double_size_mantissa:0] normalized_mantissaFP;
86 19 constantin
        wire [size_mantissa + 1 : 0] unnormalized_mantissaFP, conversion_dummiesFP;
87 11 constantin
        wire [size_exponent     : 0] shift_value_when_positive_exponentFP, shift_value_when_negative_exponentFP;
88
        wire [size_exponent - 1 : 0] shift_valueFP, shft_valFP;
89 19 constantin
        wire [size_mantissa - 1 : 0] entity_to_roundFP;
90
        wire [size_mantissa : 0] dummy_entityFP;
91 11 constantin
        wire [size_exponent     : 0] exponentFP;
92
        wire dummy_bitFP;
93
 
94
        wire [max_size - 1 : 0] max_entityCP;
95
        wire [size_mantissa - 1 : 0] shifted_m_bCP;
96 19 constantin
        wire [size_mantissa + 2 : 0] adder_mantissaCP;
97
        wire [size_mantissa + 1 : 0] unnormalized_mantissaCP;
98 11 constantin
        wire [size_mantissa     : 0] rounded_mantissaCP;
99
        wire [size_mantissa - 1 : 0] r_mantissaCP;
100
        wire [size_exponent - 1 : 0] resulted_e_oCP;
101
        wire [size_mantissa - 1 : 0] resulted_m_oCP;
102
        wire [size_exponent - 1 : 0] unadjusted_exponentCP, adjust_exponentCP;
103
        wire [size_exponent - 1 : 0] exp_selectionCP;
104 19 constantin
        wire [max_size - size_mantissa : 0] dummy_bitsCP, dummy_entityCP;
105 11 constantin
        wire [max_counter - 1 : 0] lzsCP;
106
        wire init_shft_bitCP, shft_bitCP;
107
        wire lsb_shft_bitCP;
108 19 constantin
        wire [4:0] sign_cases;
109
        reg intermediar_sign;
110 11 constantin
 
111
        wire do_conversion;
112
 
113
        assign do_conversion = |conversion; //let me know if there is a conversion
114
 
115
        assign e_a_number       = a_number_i[size_mantissa + size_exponent - 1 : size_mantissa - 1];    //exponent for a_number_i
116
        assign e_b_number = b_number_i[size_mantissa + size_exponent - 1 : size_mantissa - 1];          //exponent for b_number_i
117
        assign s_a_number = a_number_i[size - size_exception_field - 1];                                                        //sign for a_number_i
118
        assign s_b_number = b_number_i[size - size_exception_field - 1];                                                        //sign for b_number_i
119
        assign sp_case_a_number = a_number_i[size - 1 : size - size_exception_field];                           //special_case for a_number_i
120
        assign sp_case_b_number = b_number_i[size - 1 : size - size_exception_field];                           //special_case for b_number_i
121
 
122
        //find the greater exponent
123
        assign a_greater_exponent = e_a_number - e_b_number;
124
        assign b_greater_exponent = e_b_number - e_a_number;
125
 
126
        //find the difference between exponents
127
        assign exp_difference   = (a_greater_exponent[size_exponent])? b_greater_exponent[size_exponent - 1 : 0] : a_greater_exponent[size_exponent - 1 : 0];
128
        assign exp_inter                = (b_greater_exponent[size_exponent])? {1'b0, e_a_number} : {1'b0, e_b_number};
129
 
130
        //set shifter always on m_b_number
131 19 constantin
        assign {m_a_number, m_b_number} = (b_greater_exponent[size_exponent])?
132
                                                                                                        {{1'b1, a_number_i[size_mantissa - 2 :0]}, {1'b1, b_number_i[size_mantissa - 2 :0]}} :
133
                                                                                                        {{1'b1, b_number_i[size_mantissa - 2 :0]}, {1'b1, a_number_i[size_mantissa - 2 :0]}};
134 11 constantin
 
135
        effective_op effective_op_instance( .a_sign(s_a_number), .b_sign(s_b_number), .sub(sub), .eff_op(eff_op));
136
 
137
 
138
        //------------------------------------------------------- start ClosePath addition and conversion
139 19 constantin
        assign {shifted_m_bCP, init_shft_bitCP} = (exp_difference)? {1'b0, m_b_number[size_mantissa-1:0]} : {m_b_number, 1'b0};
140 11 constantin
 
141
        //compute unnormalized_mantissa
142 19 constantin
        assign adder_mantissaCP = {1'b0, m_a_number, 1'b0} - {1'b0, shifted_m_bCP, init_shft_bitCP};
143 11 constantin
        assign {unnormalized_mantissaCP, shft_bitCP} =
144 19 constantin
                                                                (adder_mantissaCP[size_mantissa + 2])?  ({~adder_mantissaCP[size_mantissa + 1   : 0], ~init_shft_bitCP}) :
145
                                                                                                                                                ({adder_mantissaCP[size_mantissa + 1    : 0], init_shft_bitCP});
146 11 constantin
 
147 19 constantin
        assign max_entityCP = do_conversion? (a_number_i[size_integer-1]? (~a_number_i[max_size-1 : 0]) : a_number_i[max_size-1 : 0]) :
148
                                                                                                        {{(max_size-size_mantissa-2){1'b0}}, unnormalized_mantissaCP[size_mantissa + 1 : 0]};
149
        assign lsb_shft_bitCP = (do_conversion)? a_number_i[size_integer-1] : adder_mantissaCP[size_mantissa+2];//sign?
150 11 constantin
 
151 19 constantin
        assign max_ovfCP = do_conversion? 1'b0 : unnormalized_mantissaCP[size_mantissa + 1];
152 11 constantin
 
153
        //compute leading_zeros over unnormalized mantissa
154
        leading_zeros #(.SIZE_INT(max_size), .SIZE_COUNTER(max_counter), .PIPELINE(pipeline))
155
                leading_zeros_CP_instance (     .a(max_entityCP),
156
                                                                        .ovf(max_ovfCP),
157
                                                                        .lz(lzsCP));
158
 
159
        //compute shifting over unnormalized_mantissa
160
        shifter #(      .INPUT_SIZE(max_size),
161
                                .SHIFT_SIZE(max_counter),
162
                                .OUTPUT_SIZE(max_size + 1),
163
                                .DIRECTION(1'b1), //0=right, 1=left
164
                                .PIPELINE(pipeline),
165
                                .POSITION(pipeline_pos))
166
                shifter_CP_instance(    .a(max_entityCP),//mantissa
167
                                                                .arith(lsb_shft_bitCP),
168
                                                                .shft(lzsCP),
169
                                                                .shifted_a({r_mantissaCP, dummy_bitsCP}));
170 19 constantin
 
171
        assign dummy_entityCP = (conversion[1] & (&dummy_bitsCP[max_size - size_mantissa - 1:0]) & (~dummy_bitsCP[max_size - size_mantissa]))? (a_number_i[size_integer-1]? ~dummy_bitsCP : dummy_bitsCP) : dummy_bitsCP;
172 11 constantin
 
173 19 constantin
        assign rounded_mantissaCP = (dummy_entityCP[max_size - size_mantissa] && (r_mantissaCP[0] | (|dummy_entityCP[max_size - size_mantissa - 1 : 0 ])))?
174 11 constantin
                                                                                r_mantissaCP + 1'b1 : r_mantissaCP;
175
        assign resulted_m_oCP = (rounded_mantissaCP[size_mantissa])? rounded_mantissaCP[size_mantissa : 1] :
176
                                                                                                                                rounded_mantissaCP[size_mantissa-1:0];
177
 
178
        assign ovfCP = do_conversion? s_a_number : adder_mantissaCP[size_mantissa+1];
179
 
180 19 constantin
        assign exp_selectionCP = do_conversion? exponentCP : exp_inter - 1'b1;
181 11 constantin
        assign adjust_exponentCP = exp_selectionCP - lzsCP;
182
        assign unadjusted_exponentCP = adjust_exponentCP + size_diff_i_m;
183
 
184
        assign resulted_e_oCP = (do_conversion & ~(|max_entityCP))? bias : unadjusted_exponentCP + rounded_mantissaCP[size_mantissa];
185
        //------------------------------------------------------- end ClosePath addition and conversion
186
 
187
 
188
        //--------------------------------------------- start FarPath addition and conversion
189
        assign exponentFP = e_a_number - bias;
190
        assign shift_value_when_positive_exponentFP = max_size - 2'd2  - exponentFP[size_exponent-1 : 0];
191
        assign shift_value_when_negative_exponentFP = max_size + (~exponentFP[size_exponent-1 : 0]);
192
        assign shift_valueFP = (exponentFP[size_exponent])? shift_value_when_negative_exponentFP[size_exponent - 1 : 0] :
193
                             (shift_value_when_positive_exponentFP[size_exponent])? (~shift_value_when_positive_exponentFP[size_exponent - 1 : 0]):
194
                                                                                   shift_value_when_positive_exponentFP[size_exponent - 1 : 0];
195
        assign shft_valFP = do_conversion? shift_valueFP : exp_difference;
196
 
197
        assign convert_neg_mantissaFP = {1'b0, ~a_number_i[size_mantissa-2 : 0]};
198
        assign conversion_dummiesFP = {(size_mantissa+1){1'b1}};
199
 
200
        assign mantissa_to_shiftFP = do_conversion? (s_a_number? convert_neg_mantissaFP + 1'b1 : {1'b1, a_number_i[size_mantissa-2 : 0]}) : m_b_number;
201
        assign arith_shiftFP = do_conversion? s_a_number : 1'b0;
202
 
203
        //shift m_b_number                              
204
        shifter #(      .INPUT_SIZE(size_mantissa),
205
                                .SHIFT_SIZE(size_exponent),
206
                                .OUTPUT_SIZE(double_size_mantissa),
207
                                .DIRECTION(1'b0), //0=right, 1=left
208
                                .PIPELINE(pipeline),
209
                                .POSITION(pipeline_pos))
210
                m_b_shifter_FP_instance(        .a(mantissa_to_shiftFP),
211
                                                                        .arith(arith_shiftFP),
212
                                                                        .shft(shft_valFP),
213
                                                                        .shifted_a({shifted_m_bFP, initial_rounding_bitsFP}));
214
 
215
        assign max_entityFP = {s_a_number, shifted_m_bFP[size_mantissa-1 : 0], initial_rounding_bitsFP[size_mantissa-1 : size_mantissa - size_diff_i_m + 1]};
216
 
217
        //compute unnormalized_mantissa
218 19 constantin
        assign adder_mantissaFP = (eff_op)? ({1'b0, m_a_number, 1'b0} - {1'b0, shifted_m_bFP, initial_rounding_bitsFP[size_mantissa - 1]}) : ({1'b0, m_a_number, 1'b0} + {1'b0, shifted_m_bFP, initial_rounding_bitsFP[size_mantissa - 1]});
219
 
220
        //compute unnormalized_mantissa
221
        assign unnormalized_mantissaFP = (adder_mantissaFP[size_mantissa + 2])? ~adder_mantissaFP[size_mantissa + 1 : 0] : adder_mantissaFP[size_mantissa + 1 : 0];
222 11 constantin
 
223 19 constantin
        assign inter_rounding_bitsFP = ((eff_op)? ((|initial_rounding_bitsFP[size_mantissa - 2 : 0])?~initial_rounding_bitsFP[size_mantissa - 2 : 0] : initial_rounding_bitsFP[size_mantissa - 2 : 0]) : initial_rounding_bitsFP[size_mantissa - 2 : 0]);
224
 
225
        assign adjust_mantissaFP = unnormalized_mantissaFP[size_mantissa + 1]? 2'd0 :
226
                                                                                unnormalized_mantissaFP[size_mantissa]? 2'd1 : 2'd2;
227 11 constantin
 
228
        //compute shifting over unnormalized_mantissa
229
        shifter #(      .INPUT_SIZE(double_size_mantissa+1),
230
                                .SHIFT_SIZE(size_exponent),
231
                                .OUTPUT_SIZE(double_size_mantissa+2),
232
                                .DIRECTION(1'b1),
233
                                .PIPELINE(pipeline),
234
                                .POSITION(pipeline_pos))
235
                unnormalized_no_shifter_FP_instance(.a({unnormalized_mantissaFP, inter_rounding_bitsFP}),
236 19 constantin
                                                                                        .arith(inter_rounding_bitsFP[0]),
237 11 constantin
                                                                                        .shft(adjust_mantissaFP),
238
                                                                                        .shifted_a({normalized_mantissaFP, dummy_bitFP}));
239
 
240 19 constantin
        assign correction = do_conversion? 1'b0 :
241
                                                eff_op? ((|initial_rounding_bitsFP[size_mantissa - 2 : 0])?
242
                                                                ((adder_mantissaFP[0] | ((~adder_mantissaFP[0]) & (~adder_mantissaFP[size_mantissa]) & (~initial_rounding_bitsFP[size_mantissa - 1])
243
                                                                                & (~(&{normalized_mantissaFP[size_mantissa-1 : 0],dummy_bitFP}))))? 1'b1 : 1'b0) : 1'b0) : 1'b0;
244
 
245
 
246
        assign entity_to_roundFP = do_conversion? max_entityFP[size_mantissa-1 : 0] : normalized_mantissaFP[double_size_mantissa : double_size_mantissa - size_mantissa + 1];
247
        assign dummy_entityFP = do_conversion? {initial_rounding_bitsFP[size_mantissa - size_diff_i_m : 0], {size_diff_i_m{1'b0}}} : normalized_mantissaFP[double_size_mantissa - size_mantissa: 0];
248
 
249 11 constantin
        //instantiate rounding_component
250
        rounding #(     .SIZE_MOST_S_MANTISSA(size_mantissa),
251
                                .SIZE_LEAST_S_MANTISSA(size_mantissa + 2'd1))
252 19 constantin
                rounding_FP_instance(   .unrounded_mantissa(entity_to_roundFP),
253
                                                                .dummy_bits(dummy_entityFP),
254
                                                                .correction(correction),
255 11 constantin
                                                                .rounded_mantissa(resulted_inter_m_oFP));
256
 
257 19 constantin
        assign resulted_m_oFP = resulted_inter_m_oFP;
258 11 constantin
        assign unadjusted_exponentFP = exp_inter - adjust_mantissaFP;
259
        assign resulted_e_oFP = do_conversion? max_entityFP[size_mantissa+size_exponent-2 : size_mantissa-1] : unadjusted_exponentFP + 1'b1;
260
        //-------------------------------------------------------- end FarPath addition and conversion
261
 
262
 
263 19 constantin
        assign set_b_sp_case = do_conversion? zero : sp_case_b_number;
264
 
265 11 constantin
        //compute exception_field
266
        special_cases   #(      .size_exception_field(size_exception_field),
267
                                                .zero(zero),
268
                                                .normal_number(normal_number),
269
                                                .infinity(infinity),
270
                                                .NaN(NaN))
271
                special_cases_instance( .sp_case_a_number(sp_case_a_number),
272 19 constantin
                                                                .sp_case_b_number(set_b_sp_case),
273
                                                                .sp_case_result_o(resulted_exception_field));
274
 
275
        //set zero_flag in case of equal numbers
276
        assign zero_flag = ((exp_difference > 1 | !eff_op) & conversion != int_to_FP)? ~(|resulted_m_oFP) : ~(|resulted_m_oCP);
277 17 constantin
 
278 19 constantin
        assign sign_cases = {eff_op, s_a_number, s_b_number, a_greater_exponent[size_exponent], b_greater_exponent[size_exponent]};
279 17 constantin
 
280 19 constantin
        always
281
                @(*)
282
        begin
283
                case (sign_cases)
284
                        5'b00000:       intermediar_sign = 1'b0;
285
                        5'b00001:       intermediar_sign = 1'b0;
286
                        5'b00010:       intermediar_sign = 1'b0;
287
 
288
                        5'b10000:       intermediar_sign = ~max_ovfCP;
289
                        5'b10001:       intermediar_sign = 1'b0;
290
                        5'b10010:       intermediar_sign = 1'b1;
291
 
292
                        5'b10100:       intermediar_sign = ~max_ovfCP;
293
                        5'b10101:       intermediar_sign = 1'b0;
294
                        5'b10110:       intermediar_sign = 1'b1;
295
 
296
                        5'b00100:       intermediar_sign = 1'b0;
297
                        5'b00101:       intermediar_sign = 1'b0;
298
                        5'b00110:       intermediar_sign = 1'b0;
299
 
300
                        5'b11000:       intermediar_sign = max_ovfCP;
301
                        5'b11001:       intermediar_sign = 1'b1;
302
                        5'b11010:       intermediar_sign = 1'b0;
303
 
304
                        5'b01000:       intermediar_sign = 1'b1;
305
                        5'b01001:       intermediar_sign = 1'b1;
306
                        5'b01010:       intermediar_sign = 1'b1;
307
 
308
                        5'b01100:       intermediar_sign = 1'b1;
309
                        5'b01101:       intermediar_sign = 1'b1;
310
                        5'b01110:       intermediar_sign = 1'b1;
311
 
312
                        5'b11100:       intermediar_sign = max_ovfCP;
313
                        5'b11101:       intermediar_sign = 1'b1;
314
                        5'b11110:       intermediar_sign = 1'b0;
315
 
316
                        default: intermediar_sign = 1'b1;
317
                endcase
318
        end
319 11 constantin
 
320 19 constantin
        assign resulted_sign = do_conversion? s_a_number : intermediar_sign;
321 11 constantin
 
322 19 constantin
        assign resulted_number_o =      conversion[0]? {3'd0, resulted_e_oFP, resulted_m_oFP[size_mantissa-2 : 0]} :
323
                                                                        conversion[1]? {normal_number, a_number_i[size_integer - 1],resulted_e_oCP, resulted_m_oCP[size_mantissa-2 : 0]} :
324
                                                                        (zero_flag)? {size{1'b0}} :
325
                                                                                (!sp_case_a_number)? {b_number_i[size-1 : size-size_exception_field], eff_op ^ s_b_number, b_number_i[size-1-size_exception_field-1 : 0]} :
326
                                                                                        (!sp_case_b_number)? {a_number_i[size-1 : 0]} :
327
                                                                                                        ((exp_difference > 1 | !eff_op) & conversion != int_to_FP)?
328 11 constantin
                                                                                                        {resulted_exception_field, resulted_sign, resulted_e_oFP, resulted_m_oFP[size_mantissa-2 : 0]}:
329
                                                                                                        {resulted_exception_field, resulted_sign, resulted_e_oCP, resulted_m_oCP[size_mantissa-2 : 0]};
330
endmodule

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