comparison gcc/config/pdp11/pdp11-modes.def @ 131:84e7813d76e9

gcc-8.2
author mir3636
date Thu, 25 Oct 2018 07:37:49 +0900
parents 04ced10e8804
children 1830386684a0
comparison
equal deleted inserted replaced
111:04ced10e8804 131:84e7813d76e9
1 /* Definitions of target machine for GNU compiler, for the pdp-11 1 /* Definitions of target machine for GNU compiler, for the pdp-11
2 Copyright (C) 2002-2017 Free Software Foundation, Inc. 2 Copyright (C) 2002-2018 Free Software Foundation, Inc.
3 Contributed by Michael K. Gschwind (mike@vlsivie.tuwien.ac.at). 3 Contributed by Michael K. Gschwind (mike@vlsivie.tuwien.ac.at).
4 4
5 This file is part of GCC. 5 This file is part of GCC.
6 6
7 GCC is free software; you can redistribute it and/or modify 7 GCC is free software; you can redistribute it and/or modify
17 You should have received a copy of the GNU General Public License 17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see 18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */ 19 <http://www.gnu.org/licenses/>. */
20 20
21 /* Add any extra modes needed to represent the condition code. 21 /* Add any extra modes needed to represent the condition code.
22 CCFPmode is used for FPU, but should we use a separate reg? */
23 22
24 CC_MODE (CCFP); 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
25 RESET_FLOAT_FORMAT (SF, pdp11_f_format); 43 RESET_FLOAT_FORMAT (SF, pdp11_f_format);
26 RESET_FLOAT_FORMAT (DF, pdp11_d_format); 44 RESET_FLOAT_FORMAT (DF, pdp11_d_format);