source: trunk/src/binutils/gas/expr.h@ 2410

Last change on this file since 2410 was 610, checked in by bird, 22 years ago

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1/* expr.h -> header file for expr.c
2 Copyright 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000
3 Free Software Foundation, Inc.
4
5 This file is part of GAS, the GNU Assembler.
6
7 GAS is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
10 any later version.
11
12 GAS is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GAS; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
20 02111-1307, USA. */
21
22/*
23 * By popular demand, we define a struct to represent an expression.
24 * This will no doubt mutate as expressions become baroque.
25 *
26 * Currently, we support expressions like "foo OP bar + 42". In other
27 * words we permit a (possibly undefined) symbol, a (possibly
28 * undefined) symbol and the operation used to combine the symbols,
29 * and an (absolute) augend. RMS says this is so we can have 1-pass
30 * assembly for any compiler emissions, and a 'case' statement might
31 * emit 'undefined1 - undefined2'.
32 *
33 * The type of an expression used to be stored as a segment. That got
34 * confusing because it overloaded the concept of a segment. I added
35 * an operator field, instead.
36 */
37
38/* This is the type of an expression. The operator types are also
39 used while parsing an expression.
40
41 NOTE: This enumeration must match the op_rank array in expr.c. */
42
43typedef enum {
44 /* An illegal expression. */
45 O_illegal,
46 /* A nonexistent expression. */
47 O_absent,
48 /* X_add_number (a constant expression). */
49 O_constant,
50 /* X_add_symbol + X_add_number. */
51 O_symbol,
52 /* X_add_symbol + X_add_number - the base address of the image. */
53 O_symbol_rva,
54 /* A register (X_add_number is register number). */
55 O_register,
56 /* A big value. If X_add_number is negative or 0, the value is in
57 generic_floating_point_number. Otherwise the value is in
58 generic_bignum, and X_add_number is the number of LITTLENUMs in
59 the value. */
60 O_big,
61 /* (- X_add_symbol) + X_add_number. */
62 O_uminus,
63 /* (~ X_add_symbol) + X_add_number. */
64 O_bit_not,
65 /* (! X_add_symbol) + X_add_number. */
66 O_logical_not,
67 /* (X_add_symbol * X_op_symbol) + X_add_number. */
68 O_multiply,
69 /* (X_add_symbol / X_op_symbol) + X_add_number. */
70 O_divide,
71 /* (X_add_symbol % X_op_symbol) + X_add_number. */
72 O_modulus,
73 /* (X_add_symbol << X_op_symbol) + X_add_number. */
74 O_left_shift,
75 /* (X_add_symbol >> X_op_symbol) + X_add_number. */
76 O_right_shift,
77 /* (X_add_symbol | X_op_symbol) + X_add_number. */
78 O_bit_inclusive_or,
79 /* (X_add_symbol |~ X_op_symbol) + X_add_number. */
80 O_bit_or_not,
81 /* (X_add_symbol ^ X_op_symbol) + X_add_number. */
82 O_bit_exclusive_or,
83 /* (X_add_symbol & X_op_symbol) + X_add_number. */
84 O_bit_and,
85 /* (X_add_symbol + X_op_symbol) + X_add_number. */
86 O_add,
87 /* (X_add_symbol - X_op_symbol) + X_add_number. */
88 O_subtract,
89 /* (X_add_symbol == X_op_symbol) + X_add_number. */
90 O_eq,
91 /* (X_add_symbol != X_op_symbol) + X_add_number. */
92 O_ne,
93 /* (X_add_symbol < X_op_symbol) + X_add_number. */
94 O_lt,
95 /* (X_add_symbol <= X_op_symbol) + X_add_number. */
96 O_le,
97 /* (X_add_symbol >= X_op_symbol) + X_add_number. */
98 O_ge,
99 /* (X_add_symbol > X_op_symbol) + X_add_number. */
100 O_gt,
101 /* (X_add_symbol && X_op_symbol) + X_add_number. */
102 O_logical_and,
103 /* (X_add_symbol || X_op_symbol) + X_add_number. */
104 O_logical_or,
105 /* X_op_symbol [ X_add_symbol ] */
106 O_index,
107 /* machine dependent operators */
108 O_md1, O_md2, O_md3, O_md4, O_md5, O_md6, O_md7, O_md8,
109 O_md9, O_md10, O_md11, O_md12, O_md13, O_md14, O_md15, O_md16,
110 O_md17, O_md18, O_md19, O_md20, O_md21, O_md22, O_md23, O_md24,
111 O_md25, O_md26, O_md27, O_md28, O_md29, O_md30, O_md31, O_md32,
112 /* this must be the largest value */
113 O_max
114} operatorT;
115
116typedef struct expressionS {
117 /* The main symbol. */
118 symbolS *X_add_symbol;
119 /* The second symbol, if needed. */
120 symbolS *X_op_symbol;
121 /* A number to add. */
122 offsetT X_add_number;
123
124 /* The type of the expression. We can't assume that an arbitrary
125 compiler can handle a bitfield of enum type. FIXME: We could
126 check this using autoconf. */
127#ifdef __GNUC__
128 operatorT X_op : 8;
129#else
130 unsigned char X_op;
131#endif
132
133 /* Non-zero if X_add_number should be regarded as unsigned. This is
134 only valid for O_constant expressions. It is only used when an
135 O_constant must be extended into a bignum (i.e., it is not used
136 when performing arithmetic on these values).
137 FIXME: This field is not set very reliably. */
138 unsigned int X_unsigned : 1;
139
140 /* 7 additional bits can be defined if needed. */
141
142 /* Machine dependent field */
143 unsigned short X_md;
144} expressionS;
145
146/* "result" should be type (expressionS *). */
147#define expression(result) expr (0, result)
148
149/* If an expression is O_big, look here for its value. These common
150 data may be clobbered whenever expr() is called. */
151/* Flonums returned here. Big enough to hold most precise flonum. */
152extern FLONUM_TYPE generic_floating_point_number;
153/* Bignums returned here. */
154extern LITTLENUM_TYPE generic_bignum[];
155/* Number of littlenums in above. */
156#define SIZE_OF_LARGE_NUMBER (20)
157
158typedef char operator_rankT;
159
160extern char get_symbol_end PARAMS ((void));
161extern void expr_begin PARAMS ((void));
162extern void expr_set_precedence PARAMS ((void));
163extern segT expr PARAMS ((int rank, expressionS * resultP));
164extern unsigned int get_single_number PARAMS ((void));
165extern symbolS *make_expr_symbol PARAMS ((expressionS * expressionP));
166extern int expr_symbol_where
167 PARAMS ((symbolS *, char **, unsigned int *));
168
169extern symbolS *expr_build_uconstant PARAMS ((offsetT));
170extern symbolS *expr_build_unary PARAMS ((operatorT, symbolS *));
171extern symbolS *expr_build_binary PARAMS ((operatorT, symbolS *, symbolS *));
172extern symbolS *expr_build_dot PARAMS ((void));
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