74 lines
2.6 KiB
C
74 lines
2.6 KiB
C
/* expr.h -> header file for expr.c
|
|
Copyright (C) 1987, 1992 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 2, 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. */
|
|
|
|
/*
|
|
* 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
|
|
* emissions, 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", above */
|
|
symbolS *X_subtract_symbol; /* "bar", above */
|
|
offsetT X_add_number; /* 42, above -- must be signed */
|
|
/* What segment (expr type)? */
|
|
segT X_seg;
|
|
}
|
|
|
|
expressionS;
|
|
|
|
/* "result" should be type (expressionS *). */
|
|
#define expression(result) expr(0,result)
|
|
|
|
/* If an expression is SEG_BIG, look here for its value. These common
|
|
data may be clobbered whenever expr() is called. */
|
|
/* Flonums returned here. Big enough to hold most precise flonum. */
|
|
extern FLONUM_TYPE generic_floating_point_number;
|
|
/* Bignums returned here. */
|
|
extern LITTLENUM_TYPE generic_bignum[];
|
|
/* Number of littlenums in above. */
|
|
#define SIZE_OF_LARGE_NUMBER (20)
|
|
|
|
typedef char operator_rankT;
|
|
|
|
char get_symbol_end PARAMS ((void));
|
|
segT expr PARAMS ((int rank, expressionS * resultP));
|
|
unsigned int get_single_number PARAMS ((void));
|
|
|
|
/* end of expr.h */
|