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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
library ieee_proposed; use ieee_proposed.mechanical_systems.all;
entity ball is
end entity ball;
----------------------------------------------------------------
architecture bouncer of ball is
quantity v : velocity := 0.0;
quantity s : displacement := 10.0;
constant g : real := 9.81;
constant air_res : real := 0.1;
begin
if v'above(0.0) use
v'dot == -g - v**2*air_res;
else
v'dot == -g + v**2*air_res;
end use;
reversal_tester : process is
begin
wait on s'above(0.0);
break v => -v when s < 0.0;
end process reversal_tester;
s'dot == v;
end architecture bouncer;
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