diff options
Diffstat (limited to 'testsuite/vests/vhdl-93/ashenden/compliant/ch_07_fg_07_05.vhd')
-rw-r--r-- | testsuite/vests/vhdl-93/ashenden/compliant/ch_07_fg_07_05.vhd | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/testsuite/vests/vhdl-93/ashenden/compliant/ch_07_fg_07_05.vhd b/testsuite/vests/vhdl-93/ashenden/compliant/ch_07_fg_07_05.vhd new file mode 100644 index 000000000..4d07810db --- /dev/null +++ b/testsuite/vests/vhdl-93/ashenden/compliant/ch_07_fg_07_05.vhd @@ -0,0 +1,93 @@ + +-- 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: ch_07_fg_07_05.vhd,v 1.2 2001-10-26 16:29:34 paw Exp $ +-- $Revision: 1.2 $ +-- +-- --------------------------------------------------------------------- + +entity fg_07_05 is +end entity fg_07_05; + + +architecture interpreter of fg_07_05 is + + subtype word is bit_vector(31 downto 0); + + signal address_bus, data_bus_in : word := X"0000_0000"; + signal mem_read, mem_request, mem_ready, reset : bit := '0'; + +begin + + -- code from book + + instruction_interpreter : process is + + -- . . . + + -- not in book + variable mem_address_reg, mem_data_reg : word; + -- end not in book + + procedure read_memory is + begin + address_bus <= mem_address_reg; + mem_read <= '1'; + mem_request <= '1'; + wait until mem_ready = '1' or reset = '1'; + if reset = '1' then + return; + end if; + mem_data_reg := data_bus_in; + mem_request <= '0'; + wait until mem_ready = '0'; + end procedure read_memory; + + begin + -- . . . -- initialization + -- not in book + if reset = '1' then + wait until reset = '0'; + end if; + -- end not in book + loop + -- . . . + read_memory; + exit when reset = '1'; + -- . . . + end loop; + end process instruction_interpreter; + + -- end code from book + + + memory : process is + begin + wait until mem_request = '1'; + data_bus_in <= X"1111_1111"; + mem_ready <= '1' after 10 ns; + wait until mem_request = '0'; + mem_ready <= '0' after 10 ns; + end process memory; + + reset <= '1' after 85 ns; + +end architecture interpreter; |