CristalCaveGem » LustreC » Lustrec-Tests

-- Copyright (C) 1996 Morgan Kaufmann Publishers, Inc

-- This file is part of VESTs (Vhdl tESTs).

-- VESTs is free software; you can redistribute it and/or modify it

-- under the terms of the GNU General Public License as published by the

-- Free Software Foundation; either version 2 of the License, or (at

-- your option) any later version. 

-- VESTs 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 VESTs; if not, write to the Free Software Foundation,

-- Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

-- ---------------------------------------------------------------------

--

-- $Id: ch_06_tofp-b.vhd,v 1.2 2001-10-26 16:29:34 paw Exp $

-- $Revision: 1.2 $

--

-- ---------------------------------------------------------------------

architecture behavioral of to_fp is

begin

  behavior : process (vec) is

                             variable temp : bit_vector(vec'range);

                           variable negative : boolean;

                           variable int_result : integer;

  begin

    temp := to_bitvector(vec);

    negative := temp(temp'left) = '1';

    if negative then

      temp := not temp;

    end if;

    int_result := 0;

    for index in vec'range loop	  -- sign bit of temp = '0'

      int_result := int_result * 2 + bit'pos(temp(index));

    end loop;

    if negative then

      int_result := (-int_result) - 1;

    end if;

    -- convert to floating point and scale to [-1, +1)

    r <= real(int_result) / real(2**15);

  end process behavior;

end architecture behavioral;