xref: /netbsd-src/external/gpl3/gcc.old/dist/gcc/config/pdp11/pdp11-modes.def (revision 8feb0f0b7eaff0608f8350bbfa3098827b4bb91b)
1/* Definitions of target machine for GNU compiler, for the pdp-11
2   Copyright (C) 2002-2020 Free Software Foundation, Inc.
3   Contributed by Michael K. Gschwind (mike@vlsivie.tuwien.ac.at).
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 3, or (at your option)
10any later version.
11
12GCC is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING3.  If not see
19<http://www.gnu.org/licenses/>.  */
20
21/* Add any extra modes needed to represent the condition code.
22
23   The default CCmode is the CPU condition codes, as set by compare;
24   all conditional branches are valid with this.
25
26   CCNZmode is the CPU condition code as a side effect of arithmetic
27   or logic operations where N and Z reflect sign and zero status of
28   the result, but the V bit is not meaningful.  Unsigned conditional
29   branches don't apply then (no such thing when comparing with zero)
30   and signed branches that use V need to clear V first if they are to
31   be used.  CCNZ mode appears in side effects (implicit compare with
32   zero) if V is not forced to 0 by the instruction.  In such cases, V
33   often reflects signed overflow of the operation, which means a
34   signed branch will get the sign backwards.  This applies both to
35   some float and integer operations.
36
37   These modes are used both in the FPU and the CPU, since they have
38   the same meaning, and also because the FPU condition codes are
39   copied to the CPU before being used in conditional branches.  */
40
41CC_MODE (CCNZ);
42
43RESET_FLOAT_FORMAT (SF, pdp11_f_format);
44RESET_FLOAT_FORMAT (DF, pdp11_d_format);
45