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-- $Id$
-- Copyright (C) 2009 FAUmachine Team <info@faumachine.org>.
-- This program is free software. You can redistribute it and/or modify it
-- under the terms of the GNU General Public License, either version 2 of
-- the License, or (at your option) any later version. See COPYING.
-- FIXME doesn't match the real std_logic_1164 yet.
PACKAGE std_logic_1164 IS
TYPE std_ulogic IS ('U', 'X', '0', '1', 'Z', 'W', 'L', 'H', '-');
TYPE std_ulogic_vector IS array (NATURAL range <>) of std_ulogic;
FUNCTION resolve_stdlogic(s : std_ulogic_vector) RETURN std_ulogic;
SUBTYPE std_logic IS resolve_stdlogic std_ulogic;
TYPE std_logic_vector IS array (NATURAL range <>) of std_logic;
function "xor"(l: std_ulogic; r: std_ulogic) return std_ulogic;
function "and"(l: std_ulogic; r: std_ulogic) return std_ulogic;
function "or"(l: std_ulogic; r: std_ulogic) return std_ulogic;
function "not"(o: std_ulogic) return std_ulogic;
END PACKAGE std_logic_1164;
PACKAGE BODY std_logic_1164 IS
function resolve_stdlogic(s : std_ulogic_vector) RETURN std_ulogic IS
variable ret : std_ulogic;
begin
ret := s(0);
for i in s'range loop
case s(i) is
when 'U' =>
return 'U';
when 'X' =>
case ret is
when 'U' => return 'U';
when others => ret := 'X';
end case;
when '0' =>
case ret is
when 'U' => return 'U';
when 'X' => ret := 'X';
when '0' => ret := '0';
when '1' => ret := 'X';
when 'Z' => ret := '0';
when 'W' => ret := '0';
when 'L' => ret := '0';
when 'H' => ret := '0';
when '-' => ret := 'X';
end case;
when '1' =>
case ret is
when 'U' => return 'U';
when 'X' => ret := 'X';
when '0' => ret := 'X';
when '1' => ret := '1';
when 'Z' => ret := '1';
when 'W' => ret := '1';
when 'L' => ret := '1';
when 'H' => ret := '1';
when '-' => ret := 'X';
end case;
when 'Z' =>
case ret is
when 'U' => return 'U';
when 'X' => ret := 'X';
when '0' => ret := '0';
when '1' => ret := '1';
when 'Z' => ret := 'Z';
when 'W' => ret := 'W';
when 'L' => ret := 'L';
when 'H' => ret := 'H';
when '-' => ret := 'X';
end case;
when 'W' =>
case ret is
when 'U' => return 'U';
when 'X' => ret := 'X';
when '0' => ret := '0';
when '1' => ret := '1';
when 'Z' => ret := 'W';
when 'W' => ret := 'W';
when 'L' => ret := 'W';
when 'H' => ret := 'W';
when '-' => ret := 'X';
end case;
when 'L' =>
case ret is
when 'U' => return 'U';
when 'X' => ret := 'X';
when '0' => ret := '0';
when '1' => ret := '1';
when 'Z' => ret := 'L';
when 'W' => ret := 'W';
when 'L' => ret := 'L';
when 'H' => ret := 'W';
when '-' => ret := 'X';
end case;
when 'H' =>
case ret is
when 'U' => return 'U';
when 'X' => ret := 'X';
when '0' => ret := '0';
when '1' => ret := '1';
when 'Z' => ret := 'H';
when 'W' => ret := 'W';
when 'L' => ret := 'W';
when 'H' => ret := 'H';
when '-' => ret := 'X';
end case;
when '-' =>
case ret is
when 'U' => return 'U';
when 'X' => ret := 'X';
when '0' => ret := 'X';
when '1' => ret := 'X';
when 'Z' => ret := 'X';
when 'W' => ret := 'X';
when 'L' => ret := 'X';
when 'H' => ret := 'X';
when '-' => ret := 'X';
end case;
end case;
end loop;
return ret;
end;
function "xor"(l: std_ulogic; r: std_ulogic) return std_ulogic IS
begin
case l is
when 'U' =>
return 'U';
when 'X' | 'Z' | 'W' | '-' =>
case r is
when 'U' => return 'U';
when others => return 'X';
end case;
when '0' | 'L' =>
case r is
when 'U' => return 'U';
when 'X' => return 'X';
when '0' => return '0';
when '1' => return '1';
when 'Z' => return 'X';
when 'W' => return 'X';
when 'L' => return '0';
when 'H' => return '1';
when '-' => return 'X';
end case;
when '1' | 'H' =>
case r is
when 'U' => return 'U';
when 'X' => return 'X';
when '0' => return '1';
when '1' => return '0';
when 'Z' => return 'X';
when 'W' => return 'X';
when 'L' => return '1';
when 'H' => return '0';
when '-' => return 'X';
end case;
end case;
end;
function "and"(l: std_ulogic; r: std_ulogic) return std_ulogic IS
begin
case l is
when '0' | 'L' =>
return '0';
when 'U' =>
case r is
when '0' | 'L' => return '0';
when others => return 'U';
end case;
when '1' | 'H' =>
case r is
when 'U' => return 'U';
when 'X' => return 'X';
when '0' => return '0';
when '1' => return '1';
when 'Z' => return 'X';
when 'W' => return 'X';
when 'L' => return '0';
when 'H' => return '1';
when '-' => return 'X';
end case;
when 'X' | 'Z' | 'W' | '-' =>
case r is
when 'U' => return 'U';
when 'X' => return 'X';
when '0' => return '0';
when '1' => return 'X';
when 'Z' => return 'X';
when 'W' => return 'X';
when 'L' => return '0';
when 'H' => return 'X';
when '-' => return 'X';
end case;
end case;
end;
function "or"(l: std_ulogic; r: std_ulogic) return std_ulogic IS
begin
case l is
when '1' | 'H' =>
return '1';
when 'U' =>
case r is
when '1' | 'H' => return '1';
when others => return 'U';
end case;
when '0' | 'L' =>
case r is
when 'U' => return 'U';
when 'X' => return 'X';
when '0' => return '0';
when '1' => return '1';
when 'Z' => return 'X';
when 'W' => return 'X';
when 'L' => return '0';
when 'H' => return '1';
when '-' => return 'X';
end case;
when 'X' | 'Z' | 'W' | '-' =>
case r is
when 'U' => return 'U';
when 'X' => return 'X';
when '0' => return 'X';
when '1' => return '1';
when 'Z' => return 'X';
when 'W' => return 'X';
when 'L' => return 'X';
when 'H' => return '1';
when '-' => return 'X';
end case;
end case;
end;
function "not"(o: std_ulogic) return std_ulogic IS
begin
case o is
when 'U' =>
return 'U';
when 'X' | 'Z' | 'W' | '-' =>
return 'X';
when '0' | 'L' =>
return '1';
when '1' | 'H' =>
return '0';
end case;
end;
END PACKAGE;
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