GCC Middle and Back End API Reference
conditions.h
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1/* Definitions for condition code handling in final.cc and output routines.
2 Copyright (C) 1987-2024 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20#ifndef GCC_CONDITIONS_H
21#define GCC_CONDITIONS_H
22
23/* These are the machine-independent flags: */
24
25/* Set if the sign of the cc value is inverted:
26 output a following jump-if-less as a jump-if-greater, etc. */
27#define CC_REVERSED 1
28
29/* This bit means that the current setting of the N bit is bogus
30 and conditional jumps should use the Z bit in its place.
31 This state obtains when an extraction of a signed single-bit field
32 or an arithmetic shift right of a byte by 7 bits
33 is turned into a btst, because btst does not set the N bit. */
34#define CC_NOT_POSITIVE 2
35
36/* This bit means that the current setting of the N bit is bogus
37 and conditional jumps should pretend that the N bit is clear.
38 Used after extraction of an unsigned bit
39 or logical shift right of a byte by 7 bits is turned into a btst.
40 The btst does not alter the N bit, but the result of that shift
41 or extract is never negative. */
42#define CC_NOT_NEGATIVE 4
43
44/* This bit means that the current setting of the overflow flag
45 is bogus and conditional jumps should pretend there is no overflow. */
46/* ??? Note that for most targets this macro is misnamed as it applies
47 to the carry flag, not the overflow flag. */
48#define CC_NO_OVERFLOW 010
49
50/* This bit means that what ought to be in the Z bit
51 should be tested as the complement of the N bit. */
52#define CC_Z_IN_NOT_N 020
53
54/* This bit means that what ought to be in the Z bit
55 should be tested as the N bit. */
56#define CC_Z_IN_N 040
57
58/* Nonzero if we must invert the sense of the following branch, i.e.
59 change EQ to NE. This is not safe for IEEE floating point operations!
60 It is intended for use only when a combination of arithmetic
61 or logical insns can leave the condition codes set in a fortuitous
62 (though inverted) state. */
63#define CC_INVERTED 0100
64
65/* Nonzero if we must convert signed condition operators to unsigned.
66 This is only used by machine description files. */
67#define CC_NOT_SIGNED 0200
68
69#endif /* GCC_CONDITIONS_H */