//======================================================================
//
// adder.v
// -------
// Adder with separate carry in and carry out. Used in the montprod
// amd residue modules of the modexp core.
//
//
// Author: Peter Magnusson, Joachim Strömbergson
// Copyright (c) 2015, NORDUnet A/S All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
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//   this list of conditions and the following disclaimer.
//
// - Redistributions in binary form must reproduce the above copyright
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//
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//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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//
//======================================================================

module adder #(parameter OPW = 32)
              (
               input      [(OPW - 1) : 0]  a,
               input      [(OPW - 1) : 0]  b,
               input                       carry_in,

               output wire [(OPW - 1) : 0] sum,
               output wire                 carry_out
              );

  reg [(OPW) : 0] adder_result;

   assign sum = adder_result[(OPW - 1) : 0];
   assign carry_out = adder_result[(OPW)];

   always @*
     begin
       adder_result = {1'b0, a} + {1'b0, b} + {{OPW{1'b0}}, carry_in};
     end

endmodule // adder

//======================================================================
// EOF adder.v
//======================================================================