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/* expr.h -> header file for expr.c
Copyright (C) 1987, 1992, 1993 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. */
/*
* 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 OP bar + 42". In other
* words we permit a (possibly undefined) symbol, a (possibly
* undefined) symbol and the operation used to combine the symbols,
* 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'.
*
* The type of an expression used to be stored as a segment. That got
* confusing because it overloaded the concept of a segment. I added
* an operator field, instead.
*/
/* This is the type of an expression. The operator types are also
used while parsing an expression.
NOTE: This enumeration must match the op_rank array in expr.c. */
typedef enum
{
/* An illegal expression. */
O_illegal,
/* A nonexistent expression. */
O_absent,
/* X_add_number (a constant expression). */
O_constant,
/* X_add_symbol + X_add_number. */
O_symbol,
/* A register (X_add_number is register number). */
O_register,
/* A big value. If X_add_number is negative or 0, the value is in
generic_floating_point_number. Otherwise the value is in
generic_bignum, and X_add_number is the number of LITTLENUMs in
the value. */
O_big,
/* (- X_add_symbol) + X_add_number. */
O_uminus,
/* (~ X_add_symbol) + X_add_number. */
O_bit_not,
/* (X_add_symbol * X_op_symbol) + X_add_number. */
O_multiply,
/* (X_add_symbol / X_op_symbol) + X_add_number. */
O_divide,
/* X_add_symbol % X_op_symbol) + X_add_number. */
O_modulus,
/* X_add_symbol << X_op_symbol) + X_add_number. */
O_left_shift,
/* X_add_symbol >> X_op_symbol) + X_add_number. */
O_right_shift,
/* X_add_symbol | X_op_symbol) + X_add_number. */
O_bit_inclusive_or,
/* X_add_symbol |~ X_op_symbol) + X_add_number. */
O_bit_or_not,
/* X_add_symbol ^ X_op_symbol) + X_add_number. */
O_bit_exclusive_or,
/* X_add_symbol & X_op_symbol) + X_add_number. */
O_bit_and,
/* X_add_symbol + X_op_symbol) + X_add_number. */
O_add,
/* X_add_symbol - X_op_symbol) + X_add_number. */
O_subtract
} operatorT;
typedef struct expressionS
{
/* The type of the expression. */
operatorT X_op;
/* The main symbol. */
struct symbol *X_add_symbol;
/* The second symbol, if needed. */
struct symbol *X_op_symbol;
/* A number to add. */
offsetT X_add_number;
/* Non-zero if X_add_number should be regarded as unsigned. This is
only valid for O_constant expressions. It is only used when an
O_constant must be extended into a bignum (i.e., it is not used
when performing arithmetic on these values).
FIXME: This field is not set very reliably.
If we ever need more flags here, we can make them bitfields. */
int X_unsigned;
} expressionS;
/* "result" should be type (expressionS *). */
#define expression(result) expr (0, result)
/* If an expression is O_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));
symbolS *make_expr_symbol PARAMS ((expressionS * expressionP));
/* end of expr.h */
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