diff options
Diffstat (limited to 'testsuite/vests/vhdl-93/ashenden/compliant/ap_a_ap_a_08.vhd')
-rw-r--r-- | testsuite/vests/vhdl-93/ashenden/compliant/ap_a_ap_a_08.vhd | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/testsuite/vests/vhdl-93/ashenden/compliant/ap_a_ap_a_08.vhd b/testsuite/vests/vhdl-93/ashenden/compliant/ap_a_ap_a_08.vhd new file mode 100644 index 000000000..6d692135b --- /dev/null +++ b/testsuite/vests/vhdl-93/ashenden/compliant/ap_a_ap_a_08.vhd @@ -0,0 +1,108 @@ + +-- Copyright (C) 1996 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 + +-- --------------------------------------------------------------------- +-- +-- $Id: ap_a_ap_a_08.vhd,v 1.2 2001-10-26 16:29:33 paw Exp $ +-- $Revision: 1.2 $ +-- +-- --------------------------------------------------------------------- + +library ieee; use ieee.std_logic_1164.all; + + entity entname is + end entity entname; + + + + architecture rtl of entname is + + -- code from book + + subtype state_type is std_ulogic_vector(3 downto 0); + constant s0 : state_type := "0001"; + constant s1 : state_type := "0010"; + constant s2 : state_type := "0100"; + constant s3 : state_type := "1000"; + + -- end code from book + + signal state, next_state : state_type; + signal con1, con2, con3 : std_ulogic; + signal out1, out2 : std_ulogic; + signal clk, reset : std_ulogic; + + begin + state_logic : process (state, con1, con2, con3) is + begin + case state is + when s0 => + out1 <= '0'; + out2 <= '0'; + next_state <= s1; + when s1 => + out1 <= '1'; + if con1 = '1' then + next_state <= s2; + else + next_state <= s1; + end if; + when s2 => + out2 <= '1'; + next_state <= s3; + when s3 => + if con2 = '0' then + next_state <= s3; + elsif con3 = '0' then + out1 <= '0'; + next_state <= s2; + else + next_state <= s1; + end if; + when others => + null; + end case; + end process state_logic; + + state_register : process (clk, reset) is + begin + if reset = '0' then + state <= s0; + elsif rising_edge(clk) then + state <= next_state; + end if; + end process state_register; + + + clk_gen : process is + begin + clk <= '0', '1' after 10 ns; + wait for 20 ns; + end process clk_gen; + + reset <= '0', '1' after 40 ns; + + con1 <= '0', '1' after 100 ns, '0' after 120 ns; + + con2 <= '0', '1' after 160 ns; + + con3 <= '0', '1' after 220 ns; + + + end architecture rtl; |