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-- Copyright (C) 2002 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
entity limited is
end entity limited;
architecture test of limited is
-- code from book
function limited ( value, min, max : real ) return real is
begin
if value > max then
return max;
elsif value < min then
return min;
else
return value;
end if;
end function limited;
-- end code from book
begin
tester : process is
variable new_temperature, current_temperature, increment : real;
variable new_motor_speed, old_motor_speed,
scale_factor, error : real;
begin
current_temperature := 75.0;
increment := 10.0;
-- code from book (in text)
new_temperature := limited ( current_temperature + increment, 10.0, 100.0 );
-- end code from book
increment := 60.0;
new_temperature := limited ( current_temperature + increment, 10.0, 100.0 );
increment := -100.0;
new_temperature := limited ( current_temperature + increment, 10.0, 100.0 );
old_motor_speed := 1000.0;
scale_factor := 5.0;
error := 5.0;
-- code from book (in text)
new_motor_speed := old_motor_speed
+ scale_factor * limited ( error, -10.0, +10.0 );
-- end code from book
error := 15.0;
new_motor_speed := old_motor_speed
+ scale_factor * limited ( error, -10.0, +10.0 );
error := -20.0;
new_motor_speed := old_motor_speed
+ scale_factor * limited ( error, -10.0, +10.0 );
wait;
end process tester;
end architecture test;
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