diff options
Diffstat (limited to 'testsuite/vests/vhdl-93/ashenden/compliant/ch_09_fg_09_03.vhd')
-rw-r--r-- | testsuite/vests/vhdl-93/ashenden/compliant/ch_09_fg_09_03.vhd | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/testsuite/vests/vhdl-93/ashenden/compliant/ch_09_fg_09_03.vhd b/testsuite/vests/vhdl-93/ashenden/compliant/ch_09_fg_09_03.vhd new file mode 100644 index 000000000..d2cc16e5f --- /dev/null +++ b/testsuite/vests/vhdl-93/ashenden/compliant/ch_09_fg_09_03.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_09_fg_09_03.vhd,v 1.2 2001-10-26 16:29:34 paw Exp $ +-- $Revision: 1.2 $ +-- +-- --------------------------------------------------------------------- + +package cpu_types is + + constant word_size : positive := 16; + constant address_size : positive := 32; + + subtype word is bit_vector(word_size - 1 downto 0); + subtype address is bit_vector(address_size - 1 downto 0); + + type status_value is ( halted, idle, fetch, mem_read, mem_write, + io_read, io_write, int_ack ); + +end package cpu_types; + + + +package bit_vector_unsigned_arithmetic is + + function "+" ( bv1, bv2 : bit_vector ) return bit_vector; + +end package bit_vector_unsigned_arithmetic; + + +package body bit_vector_unsigned_arithmetic is + + function "+" ( bv1, bv2 : bit_vector ) return bit_vector is + + alias norm1 : bit_vector(1 to bv1'length) is bv1; + alias norm2 : bit_vector(1 to bv2'length) is bv2; + + variable result : bit_vector(1 to bv1'length); + variable carry : bit := '0'; + + begin + if bv1'length /= bv2'length then + report "arguments of different length" severity failure; + else + for index in norm1'reverse_range loop + result(index) := norm1(index) xor norm2(index) xor carry; + carry := ( norm1(index) and norm2(index) ) + or ( carry and ( norm1(index) or norm2(index) ) ); + end loop; + end if; + return result; + end function "+"; + +end package body bit_vector_unsigned_arithmetic; + + + + +-- code from book + +package DMA_controller_types_and_utilities is + + alias word is work.cpu_types.word; + alias address is work.cpu_types.address; + alias status_value is work.cpu_types.status_value; + + alias "+" is work.bit_vector_unsigned_arithmetic."+" + [ bit_vector, bit_vector return bit_vector ]; + + -- . . . + +end package DMA_controller_types_and_utilities; + +-- end code from book + |