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// ============================================================================

//        __

//   \\__/ o\    (C) 2006-2016  Robert Finch, Stratford

//    \  __ /    All rights reserved.

//     \/_//     robfinch<remove>@finitron.ca

//       ||

//

// This source file is free software: you can redistribute it and/or modify 

// it under the terms of the GNU Lesser General Public License as published 

// by the Free Software Foundation, either version 3 of the License, or     

// (at your option) any later version.                                      

//                                                                          

// This source file is distributed in the hope that it will be useful,      

// but WITHOUT ANY WARRANTY; without even the implied warranty of           

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            

// GNU General Public License for more details.                             

//                                                                          

// You should have received a copy of the GNU General Public License        

// along with this program.  If not, see <http://www.gnu.org/licenses/>.    

//

//      fpDecompose.v

//  - decompose floating point value

//  - parameterized width

//  - IEEE 754 representation

//

// ============================================================================

//

module fpDecompose(i, sgn, exp, man, fract, xz, mz, vz, inf, xinf, qnan, snan, nan);

parameter WID=32;

localparam MSB  = WID-1;

localparam EMSB = WID==80 ? 14 :

                  WID==64 ? 10 :

                                  WID==52 ? 10 :

                                  WID==48 ? 10 :

                                  WID==44 ? 10 :

                                  WID==42 ? 10 :

                                  WID==40 ?  9 :

                                  WID==32 ?  7 :

                                  WID==24 ?  6 : 4;

localparam FMSB = WID==80 ? 63 :

                  WID==64 ? 51 :

                                  WID==52 ? 39 :

                                  WID==48 ? 35 :

                                  WID==44 ? 31 :

                                  WID==42 ? 29 :

                                  WID==40 ? 28 :

                                  WID==32 ? 22 :

                                  WID==24 ? 15 : 9;

input [MSB:0] i;

output sgn;

output [EMSB:0] exp;

output [FMSB:0] man;

output [FMSB+1:0] fract; // mantissa with hidden bit recovered

output xz;              // denormalized - exponent is zero

output mz;              // mantissa is zero

output vz;              // value is zero (both exponent and mantissa are zero)

output inf;             // all ones exponent, zero mantissa

output xinf;    // all ones exponent

output qnan;    // nan

output snan;    // signalling nan

output nan;

// Decompose input

assign sgn = i[MSB];

assign exp = i[MSB-1:FMSB+1];

assign man = i[FMSB:0];

assign xz = !(|exp);    // denormalized - exponent is zero

assign mz = !(|man);    // mantissa is zero

assign vz = xz & mz;    // value is zero (both exponent and mantissa are zero)

assign inf = &exp & mz; // all ones exponent, zero mantissa

assign xinf = &exp;

assign qnan = &exp &  man[FMSB];

assign snan = &exp & !man[FMSB] & !mz;

assign nan = &exp & !mz;

assign fract = {!xz,i[FMSB:0]};

endmodule