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+/* expr.h -> header file for expr.c
+ Copyright (C) 1987, 92-97, 1998 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, 59 Temple Place - Suite 330, Boston, MA
+ 02111-1307, 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,
+ /* this must be the largest value */
+ O_max
+} operatorT;
+
+typedef struct expressionS
+{
+ /* 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;
+ /* 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 : 5;
+#else
+ unsigned X_op : 5;
+#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;
+} 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;
+
+extern char get_symbol_end PARAMS ((void));
+extern void expr_begin PARAMS ((void));
+extern void expr_set_precedence PARAMS ((void));
+extern segT expr PARAMS ((int rank, expressionS * resultP));
+extern unsigned int get_single_number PARAMS ((void));
+extern struct symbol *make_expr_symbol PARAMS ((expressionS * expressionP));
+extern int expr_symbol_where
+ PARAMS ((struct symbol *, char **, unsigned int *));
+
+extern struct symbol * expr_build_uconstant PARAMS ((offsetT));
+extern struct symbol * expr_build_unary PARAMS ((operatorT, struct symbol *));
+extern struct symbol * expr_build_binary
+ PARAMS ((operatorT, struct symbol *, struct symbol *));
+extern struct symbol * expr_build_dot PARAMS ((void));
+
+/* end of expr.h */