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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 cos is
port ( theta : in real; result : out real );
end entity cos;
--------------------------------------------------
architecture series of cos is
begin
summation : process (theta) is
variable sum, term : real;
variable n : natural;
begin
sum := 1.0;
term := 1.0;
n := 0;
while abs term > abs (sum / 1.0E6) loop
n := n + 2;
term := (-term) * theta**2 / real(((n-1) * n));
sum := sum + term;
end loop;
result <= sum;
end process summation;
end architecture series;
architecture fixed_length_series of cos is
begin
summation : process (theta) is
variable sum, term : real;
begin
sum := 1.0;
term := 1.0;
for n in 1 to 9 loop
term := (-term) * theta**2 / real(((2*n-1) * 2*n));
sum := sum + term;
end loop;
result <= sum;
end process summation;
end architecture fixed_length_series;
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