The files in this folder (std_logic_arith.vhdl, std_logic_unsigned.vhdl,
std_logic_signed.vhdl, std_logic_misc.vhdl, std_logic_misc-body.vhdl,
std_logic_textio.vhdl) carry
this notice, copied from them:

Copyright (c) 1990,1991,1992 by Synopsys, Inc.  All rights reserved.

This source file may be used and distributed without restriction
provided that this copyright statement is not removed from the file
and that any derivative work contains this copyright notice.
