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-- Copyright (C) 1996 Morgan Kaufmann Publishers, Inc
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-- This file is part of VESTs (Vhdl tESTs).
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-- VESTs is free software; you can redistribute it and/or modify it
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-- under the terms of the GNU General Public License as published by the
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-- Free Software Foundation; either version 2 of the License, or (at
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-- your option) any later version. 
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-- VESTs is distributed in the hope that it will be useful, but WITHOUT
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-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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-- FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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-- for more details. 
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-- You should have received a copy of the GNU General Public License
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-- along with VESTs; if not, write to the Free Software Foundation,
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-- Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
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-- ---------------------------------------------------------------------
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--
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-- $Id: ch_08_fg_08_08.vhd,v 1.3 2001-10-26 16:29:34 paw Exp $
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-- $Revision: 1.3 $
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--
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-- ---------------------------------------------------------------------
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package bit_vector_signed_arithmetic is
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  function "+" ( bv1, bv2 : bit_vector ) return bit_vector;
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  function "-" ( bv : bit_vector ) return bit_vector;
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  function "*" ( bv1, bv2 : bit_vector ) return bit_vector;
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  -- . . .
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end package bit_vector_signed_arithmetic;
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-- not in book
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library bv_utilities;
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use bv_utilities.bv_arithmetic;
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-- end not in book
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package body bit_vector_signed_arithmetic is
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  function "+" ( bv1, bv2 : bit_vector ) return bit_vector is -- . . .
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    -- not in book
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  begin
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    return bv_arithmetic."+"(bv1, bv2);
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  end function "+";
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  -- end not in book
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  function "-" ( bv : bit_vector ) return bit_vector is -- . . .
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    -- not in book
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  begin
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    return bv_arithmetic."-"(bv);
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  end function "-";
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  -- end not in book
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  function mult_unsigned ( bv1, bv2 : bit_vector ) return bit_vector is
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    -- . . .
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  begin
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    -- not in book
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    -- . . .
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    return bv_arithmetic.bv_multu(bv1, bv2);
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    -- end not in book
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  end function mult_unsigned;
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  function "*" ( bv1, bv2 : bit_vector ) return bit_vector is
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  begin
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    if bv1(bv1'left) = '0' and bv2(bv2'left) = '0' then
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      return mult_unsigned(bv1, bv2);
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    elsif bv1(bv1'left) = '0' and bv2(bv2'left) = '1' then
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      return -mult_unsigned(bv1, -bv2);
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    elsif bv1(bv1'left) = '1' and bv2(bv2'left) = '0' then
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      return -mult_unsigned(-bv1, bv2);
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    else
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      return mult_unsigned(-bv1, -bv2);
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    end if;
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  end function "*";
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  -- . . .
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end package body bit_vector_signed_arithmetic;
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-- not in book
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entity fg_08_08 is
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end entity fg_08_08;
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library bv_utilities;
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use bv_utilities.bit_vector_signed_arithmetic.all;
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use std.textio.all;
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architecture test of fg_08_08 is
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begin
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  stimulus : process is
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                       variable L : line;
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  begin
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    write(L, X"0002" + X"0005");
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    writeline(output, L);
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    write(L, X"0002" + X"FFFE");
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    writeline(output, L);
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    write(L, - X"0005");
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    writeline(output, L);
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    write(L, - X"FFFE");
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    writeline(output, L);
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    write(L, X"0002" * X"0005");
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    writeline(output, L);
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    write(L, X"0002" * X"FFFD");
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    writeline(output, L);
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    wait;
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  end process stimulus;
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end architecture test;
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-- end not in book
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