mirror of
https://github.com/freebsd/freebsd-src.git
synced 2024-11-29 08:52:46 +00:00
119 lines
4.5 KiB
C
119 lines
4.5 KiB
C
/* Definitions for condition code handling in final.c and output routines.
|
|
Copyright (C) 1987 Free Software Foundation, Inc.
|
|
|
|
This file is part of GCC.
|
|
|
|
GCC is free software; you can redistribute it and/or modify it under
|
|
the terms of the GNU General Public License as published by the Free
|
|
Software Foundation; either version 2, or (at your option) any later
|
|
version.
|
|
|
|
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
|
|
WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with GCC; see the file COPYING. If not, write to the Free
|
|
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
|
|
02111-1307, USA. */
|
|
|
|
/* None of the things in the files exist if we don't use CC0. */
|
|
|
|
#ifdef HAVE_cc0
|
|
|
|
/* The variable cc_status says how to interpret the condition code.
|
|
It is set by output routines for an instruction that sets the cc's
|
|
and examined by output routines for jump instructions.
|
|
|
|
cc_status contains two components named `value1' and `value2'
|
|
that record two equivalent expressions for the values that the
|
|
condition codes were set from. (Either or both may be null if
|
|
there is no useful expression to record.) These fields are
|
|
used for eliminating redundant test and compare instructions
|
|
in the cases where the condition codes were already set by the
|
|
previous instruction.
|
|
|
|
cc_status.flags contains flags which say that the condition codes
|
|
were set in a nonstandard manner. The output of jump instructions
|
|
uses these flags to compensate and produce the standard result
|
|
with the nonstandard condition codes. Standard flags are defined here.
|
|
The tm.h file can also define other machine-dependent flags.
|
|
|
|
cc_status also contains a machine-dependent component `mdep'
|
|
whose type, `CC_STATUS_MDEP', may be defined as a macro in the
|
|
tm.h file. */
|
|
|
|
#ifndef CC_STATUS_MDEP
|
|
#define CC_STATUS_MDEP int
|
|
#endif
|
|
|
|
#ifndef CC_STATUS_MDEP_INIT
|
|
#define CC_STATUS_MDEP_INIT 0
|
|
#endif
|
|
|
|
typedef struct {int flags; rtx value1, value2; CC_STATUS_MDEP mdep;} CC_STATUS;
|
|
|
|
/* While outputting an insn as assembler code,
|
|
this is the status BEFORE that insn. */
|
|
extern CC_STATUS cc_prev_status;
|
|
|
|
/* While outputting an insn as assembler code,
|
|
this is being altered to the status AFTER that insn. */
|
|
extern CC_STATUS cc_status;
|
|
|
|
/* These are the machine-independent flags: */
|
|
|
|
/* Set if the sign of the cc value is inverted:
|
|
output a following jump-if-less as a jump-if-greater, etc. */
|
|
#define CC_REVERSED 1
|
|
|
|
/* This bit means that the current setting of the N bit is bogus
|
|
and conditional jumps should use the Z bit in its place.
|
|
This state obtains when an extraction of a signed single-bit field
|
|
or an arithmetic shift right of a byte by 7 bits
|
|
is turned into a btst, because btst does not set the N bit. */
|
|
#define CC_NOT_POSITIVE 2
|
|
|
|
/* This bit means that the current setting of the N bit is bogus
|
|
and conditional jumps should pretend that the N bit is clear.
|
|
Used after extraction of an unsigned bit
|
|
or logical shift right of a byte by 7 bits is turned into a btst.
|
|
The btst does not alter the N bit, but the result of that shift
|
|
or extract is never negative. */
|
|
#define CC_NOT_NEGATIVE 4
|
|
|
|
/* This bit means that the current setting of the overflow flag
|
|
is bogus and conditional jumps should pretend there is no overflow. */
|
|
/* ??? Note that for most targets this macro is misnamed as it applies
|
|
to the carry flag, not the overflow flag. */
|
|
#define CC_NO_OVERFLOW 010
|
|
|
|
/* This bit means that what ought to be in the Z bit
|
|
should be tested as the complement of the N bit. */
|
|
#define CC_Z_IN_NOT_N 020
|
|
|
|
/* This bit means that what ought to be in the Z bit
|
|
should be tested as the N bit. */
|
|
#define CC_Z_IN_N 040
|
|
|
|
/* Nonzero if we must invert the sense of the following branch, i.e.
|
|
change EQ to NE. This is not safe for IEEE floating point operations!
|
|
It is intended for use only when a combination of arithmetic
|
|
or logical insns can leave the condition codes set in a fortuitous
|
|
(though inverted) state. */
|
|
#define CC_INVERTED 0100
|
|
|
|
/* Nonzero if we must convert signed condition operators to unsigned.
|
|
This is only used by machine description files. */
|
|
#define CC_NOT_SIGNED 0200
|
|
|
|
/* This is how to initialize the variable cc_status.
|
|
final does this at appropriate moments. */
|
|
|
|
#define CC_STATUS_INIT \
|
|
(cc_status.flags = 0, cc_status.value1 = 0, cc_status.value2 = 0, \
|
|
CC_STATUS_MDEP_INIT)
|
|
|
|
#endif
|