1/* Definitions for condition code handling in final.c and output routines.
2   Copyright (C) 1987-2015 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/* None of the things in the files exist if we don't use CC0.  */
24
25#ifdef HAVE_cc0
26
27/* The variable cc_status says how to interpret the condition code.
28   It is set by output routines for an instruction that sets the cc's
29   and examined by output routines for jump instructions.
30
31   cc_status contains two components named `value1' and `value2'
32   that record two equivalent expressions for the values that the
33   condition codes were set from.  (Either or both may be null if
34   there is no useful expression to record.)  These fields are
35   used for eliminating redundant test and compare instructions
36   in the cases where the condition codes were already set by the
37   previous instruction.
38
39   cc_status.flags contains flags which say that the condition codes
40   were set in a nonstandard manner.  The output of jump instructions
41   uses these flags to compensate and produce the standard result
42   with the nonstandard condition codes.  Standard flags are defined here.
43   The tm.h file can also define other machine-dependent flags.
44
45   cc_status also contains a machine-dependent component `mdep'
46   whose type, `CC_STATUS_MDEP', may be defined as a macro in the
47   tm.h file.  */
48
49#ifndef CC_STATUS_MDEP
50#define CC_STATUS_MDEP int
51#endif
52
53#ifndef CC_STATUS_MDEP_INIT
54#define CC_STATUS_MDEP_INIT 0
55#endif
56
57struct CC_STATUS {int flags; rtx value1, value2; CC_STATUS_MDEP mdep;};
58
59/* While outputting an insn as assembler code,
60   this is the status BEFORE that insn.  */
61extern CC_STATUS cc_prev_status;
62
63/* While outputting an insn as assembler code,
64   this is being altered to the status AFTER that insn.  */
65extern CC_STATUS cc_status;
66
67/* These are the machine-independent flags:  */
68
69/* Set if the sign of the cc value is inverted:
70   output a following jump-if-less as a jump-if-greater, etc.  */
71#define CC_REVERSED 1
72
73/* This bit means that the current setting of the N bit is bogus
74   and conditional jumps should use the Z bit in its place.
75   This state obtains when an extraction of a signed single-bit field
76   or an arithmetic shift right of a byte by 7 bits
77   is turned into a btst, because btst does not set the N bit.  */
78#define CC_NOT_POSITIVE 2
79
80/* This bit means that the current setting of the N bit is bogus
81   and conditional jumps should pretend that the N bit is clear.
82   Used after extraction of an unsigned bit
83   or logical shift right of a byte by 7 bits is turned into a btst.
84   The btst does not alter the N bit, but the result of that shift
85   or extract is never negative.  */
86#define CC_NOT_NEGATIVE 4
87
88/* This bit means that the current setting of the overflow flag
89   is bogus and conditional jumps should pretend there is no overflow.  */
90/* ??? Note that for most targets this macro is misnamed as it applies
91   to the carry flag, not the overflow flag.  */
92#define CC_NO_OVERFLOW 010
93
94/* This bit means that what ought to be in the Z bit
95   should be tested as the complement of the N bit.  */
96#define CC_Z_IN_NOT_N 020
97
98/* This bit means that what ought to be in the Z bit
99   should be tested as the N bit.  */
100#define CC_Z_IN_N 040
101
102/* Nonzero if we must invert the sense of the following branch, i.e.
103   change EQ to NE.  This is not safe for IEEE floating point operations!
104   It is intended for use only when a combination of arithmetic
105   or logical insns can leave the condition codes set in a fortuitous
106   (though inverted) state.  */
107#define CC_INVERTED 0100
108
109/* Nonzero if we must convert signed condition operators to unsigned.
110   This is only used by machine description files.  */
111#define CC_NOT_SIGNED 0200
112
113/* This is how to initialize the variable cc_status.
114   final does this at appropriate moments.  */
115
116#define CC_STATUS_INIT  \
117 (cc_status.flags = 0, cc_status.value1 = 0, cc_status.value2 = 0,  \
118  CC_STATUS_MDEP_INIT)
119
120#endif
121
122#endif /* GCC_CONDITIONS_H */
123