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

//        __

//   \\__/ o\    (C) 2006-2019  Robert Finch, Waterloo

//    \  __ /    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/>.    

//                                                                          

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

`include "fpConfig.sv"

module F80ToF32(a, o);

input [79:0] a;

output [31:0] o;

reg signo;

reg [7:0] expo;

reg [22:0] mano;

assign o = {signo,expo,mano};

wire signi;

wire [14:0] expi;

wire [63:0] mani;

wire xinf;      // exponent infinite

wire vz;        // value zero

wire xz;        // exponent zero

fpDecomp #(80) u1 (.i(a), .sgn(signi), .exp(expi), .man(mani), .xinf(xinf), .xz(xz), .vz(vz) );

always @*

begin

  // sign out always just = sign in

  signo = signi;

  // special check for zero

  if (vz) begin

    expo <= 0;

    mano <= 0;

  end

  // convert infinity / nan

  // infinity in = infinity out

  else if (xinf) begin

    expo <= 8'h7f;

    mano <= mani[63:41];

  end

  // convert denormal

  // a denormal was really a number with an exponent of -126

  // this value is easily represented in the double format

  // it may be possible to normalize the value if it isn't

  // zero

  else if (xz) begin

    expo <= 8'h00;

    mano <= 23'h0;

  end

  // convert typical number

  // adjust exponent, copy mantissa

  else begin

        if (expi < 15'h3fff - 8'h7f) begin

                expo <= 8'h00;  // zero

                mano <= 23'h0;

        end

        else if (expi > 15'h3fff + 8'h7f) begin

                expo <= 8'hFF;  // Infinity

                mano <= 23'h0;

        end

        else begin

        expo <= expi - 15'h3fff + 8'h7f;

        mano <= mani[63:41];

    end

  end

end

endmodule