diff options
Diffstat (limited to 'testsuite/vests/vhdl-ams/ashenden/compliant/subprograms/addu.vhd')
-rw-r--r-- | testsuite/vests/vhdl-ams/ashenden/compliant/subprograms/addu.vhd | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/testsuite/vests/vhdl-ams/ashenden/compliant/subprograms/addu.vhd b/testsuite/vests/vhdl-ams/ashenden/compliant/subprograms/addu.vhd new file mode 100644 index 0000000..377f266 --- /dev/null +++ b/testsuite/vests/vhdl-ams/ashenden/compliant/subprograms/addu.vhd @@ -0,0 +1,72 @@ + +-- 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 addu is +end entity addu; + + +architecture test of addu is + + subtype word32 is bit_vector(31 downto 0); + + -- code in book + + procedure addu ( a, b : in word32; + result : out word32; overflow : out boolean ) is + variable sum : word32; + variable carry : bit := '0'; + begin + for index in sum'reverse_range loop + sum(index) := a(index) xor b(index) xor carry; + carry := ( a(index) and b(index) ) or ( carry and ( a(index) xor b(index) ) ); + end loop; + result := sum; + overflow := carry = '1'; + end procedure addu; + + -- end code in book + +begin + + stimulus : process is + + -- code in book (in text) + + variable PC, next_PC : word32; + variable overflow_flag : boolean; + -- . . . + + -- end code in book + + begin + PC := X"0000_0010"; + + -- code in book (in text) + + addu ( PC, X"0000_0004", next_PC, overflow_flag); + + -- end code in book + + PC := X"FFFF_FFFC"; + addu ( PC, X"0000_0004", next_PC, overflow_flag); + + wait; + end process stimulus; + +end architecture test; |