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/* expr.h -> header file for expr.c

   Copyright (C) 1987-2015 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 3, 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, 51 Franklin Street - Fifth Floor, Boston, MA

   02110-1301, 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,

  /* X_add_symbol + X_add_number - the base address of the image.  */

  O_symbol_rva,

  /* 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_add_number.  */

  O_logical_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,

  /* (X_add_symbol == X_op_symbol) + X_add_number.  */

  O_eq,

  /* (X_add_symbol != X_op_symbol) + X_add_number.  */

  O_ne,

  /* (X_add_symbol < X_op_symbol) + X_add_number.  */

  O_lt,

  /* (X_add_symbol <= X_op_symbol) + X_add_number.  */

  O_le,

  /* (X_add_symbol >= X_op_symbol) + X_add_number.  */

  O_ge,

  /* (X_add_symbol > X_op_symbol) + X_add_number.  */

  O_gt,

  /* (X_add_symbol && X_op_symbol) + X_add_number.  */

  O_logical_and,

  /* (X_add_symbol || X_op_symbol) + X_add_number.  */

  O_logical_or,

  /* X_op_symbol [ X_add_symbol ] */

  O_index,

  /* machine dependent operators */

  O_md1,  O_md2,  O_md3,  O_md4,  O_md5,  O_md6,  O_md7,  O_md8,

  O_md9,  O_md10, O_md11, O_md12, O_md13, O_md14, O_md15, O_md16,

  O_md17, O_md18, O_md19, O_md20, O_md21, O_md22, O_md23, O_md24,

  O_md25, O_md26, O_md27, O_md28, O_md29, O_md30, O_md31, O_md32,

  /* this must be the largest value */

  O_max

} operatorT;

typedef struct expressionS {

  /* The main symbol.  */

  symbolS *X_add_symbol;

  /* The second symbol, if needed.  */

  symbolS *X_op_symbol;

  /* A number to add.  */

  offsetT X_add_number;

  /* The type of the expression.  We can't assume that an arbitrary

     compiler can handle a bitfield of enum type.  FIXME: We could

     check this using autoconf.  */

#ifdef __GNUC__

  operatorT X_op : 8;

#else

  unsigned char X_op;

#endif

  /* 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.  */

  unsigned int X_unsigned : 1;

  /* This is used to implement "word size + 1 bit" arithmetic, so that e.g.

     expressions used with .sleb128 directives can use the full range available

     for an unsigned word, but can also properly represent all values of a

     signed word.  */

  unsigned int X_extrabit : 1;

  /* 7 additional bits can be defined if needed.  */

  /* Machine dependent field */

  unsigned short X_md;

} expressionS;

enum expr_mode

{

  expr_evaluate,

  expr_normal,

  expr_defer

};

/* "result" should be type (expressionS *).  */

#define expression(result) expr (0, result, expr_normal)

#define expression_and_evaluate(result) expr (0, result, expr_evaluate)

#define deferred_expression(result) expr (0, result, expr_defer)

/* 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;

extern char get_symbol_name (char **);

extern char restore_line_pointer (char);

extern void expr_begin (void);

extern void expr_set_precedence (void);

extern void expr_set_rank (operatorT, operator_rankT);

extern void add_to_result (expressionS *, offsetT, int);

extern void subtract_from_result (expressionS *, offsetT, int);

extern segT expr (int, expressionS *, enum expr_mode);

extern unsigned int get_single_number (void);

extern symbolS *make_expr_symbol (expressionS * expressionP);

extern int expr_symbol_where (symbolS *, char **, unsigned int *);

extern void current_location (expressionS *);

extern symbolS *expr_build_uconstant (offsetT);

extern symbolS *expr_build_dot (void);

int resolve_expression (expressionS *);