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-- 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_11_fg_11_05.vhd,v 1.1.1.1 2001-08-22 18:20:48 paw Exp $
-- $Revision: 1.1.1.1 $
--
-- ---------------------------------------------------------------------
package words is
type X01Z is ('X', '0', '1', 'Z');
type uword is array (0 to 31) of X01Z;
type uword_vector is array (natural range <>) of uword;
function resolve_word ( contribution : uword_vector ) return uword;
subtype word is resolve_word uword;
-- not in book
type ubyte is array (0 to 7) of X01Z;
-- end not in book
end package words;
--------------------------------------------------
package body words is
type table is array (X01Z, X01Z) of X01Z;
constant resolution_table : table :=
-- 'X' '0' '1' 'Z'
-- ------------------
( ( 'X', 'X', 'X', 'X' ), -- 'X'
( 'X', '0', 'X', '0' ), -- '0'
( 'X', 'X', '1', '1' ), -- '1'
( 'X', '0', '1', 'Z' ) ); -- 'Z'
function resolve_word ( contribution : uword_vector ) return uword is
variable result : uword := (others => 'Z');
begin
for index in contribution'range loop
for element in uword'range loop
result(element) :=
resolution_table( result(element), contribution(index)(element) );
end loop;
end loop;
return result;
end function resolve_word;
end package body words;
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