gcc/config/pdp11/pdp11-modes.def

   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
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along 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
  41 CC_MODE (CCNZ);
  42
  43 RESET_FLOAT_FORMAT (SF, pdp11_f_format);
  44 RESET_FLOAT_FORMAT (DF, pdp11_d_format);