This is expr.h in view mode; [Download] [Up]
/* expr.h -> header file for expr.c
Copyright (C) 1987 Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS 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 1, or (at your option)
any later version.
GAS 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 GAS; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#import "struc-symbol.h"
#import "bignum.h"
#import "flonum.h"
/*
* This table describes the use of segments as EXPRESSION types.
*
* X_seg X_add_symbol X_subtract_symbol X_add_number
* SEG_NONE no (legal) expression
* SEG_BIG * > 32 bits const.
* SEG_ABSOLUTE 0
* SEG_SECT * 0
* SEG_UNKNOWN * 0
* SEG_DIFFSECT 0 * 0
*
* The blank fields MUST be 0, and are nugatory.
* The '0' fields MAY be 0. The '*' fields MAY NOT be 0.
*
* SEG_BIG: A floating point number or an integer larger than 32 bits.
* For a floating point number:
* X_add_number is < 0
* The result is in the global variable generic_floating_point_number.
* The value in X_add_number is -'c' where c is the character that
* introduced the constant. e.g. "0f6.9" will have -'f' as a
* X_add_number value.
* For an integer larger than 32 bits:
* X_add_number > 0
* The result is in the global variable generic_bignum.
* The value in X_add_number is a count of how many littlenums it
* took to represent the bignum.
*/
typedef enum {
SEG_ABSOLUTE, /* absolute */
SEG_SECT, /* normal defined section */
SEG_DIFFSECT, /* difference between symbols in sections */
SEG_UNKNOWN, /* expression involving an undefined symbol */
SEG_NONE, /* no expression */
SEG_BIG /* bigger than 32 bits constant */
} segT;
extern char *seg_name[];
extern segT N_TYPE_seg[];
/*
* When an expression is SEG_BIG, it is in these globals (see comments above
* about SEG_BIG). This data may be clobbered whenever expr() is called.
*/
extern FLONUM_TYPE generic_floating_point_number;
extern LITTLENUM_TYPE generic_bignum[];
#define SIZE_OF_LARGE_NUMBER (20) /* Number of littlenums in above */
/* generic_bignum which is enough to */
/* hold most precise flonum. */
/*
* Abbreviations (mnemonics).
*
* O operator
* Q quantity, operand
* X eXpression
*/
/*
* By popular demand, we define a struct to represent an expression.
* This will no doubt mutate as expressions become baroque.
*
* Currently, we support expressions like "foo-bar+42".
* In other words we permit a (possibly undefined) minuend, a
* (possibly undefined) subtrahend and an (absolute) augend.
* RMS says this is so we can have 1-pass assembly for any compiler
* emmissions, and a 'case' statement might emit 'undefined1 - undefined2'.
*
* To simplify table-driven dispatch, we also have a "segment" for the
* entire expression. That way we don't require complex reasoning about
* whether particular components are defined; and we can change component
* semantics without re-working all the dispatch tables in the assembler.
* In other words the "type" of an expression is its segment.
*/
typedef struct {
symbolS *X_add_symbol; /* foo */
symbolS *X_subtract_symbol; /* bar */
long X_add_number; /* 42 (must be signed) */
segT X_seg; /* What segment (expr type) */
} expressionS;
extern segT expression(
expressionS *resultP);
extern char get_symbol_end(
void);
extern segT try_to_make_absolute(
expressionS *expressionP);
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.