1 /* expr.h -> header file for expr.c
2 Copyright (C) 1987-2023 Free Software Foundation, Inc.
4 This file is part of GAS, the GNU Assembler.
6 GAS is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GAS is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GAS; see the file COPYING. If not, write to the Free
18 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
21 /* By popular demand, we define a struct to represent an expression.
22 This will no doubt mutate as expressions become baroque.
24 Currently, we support expressions like "foo OP bar + 42". In other
25 words we permit a (possibly undefined) symbol, a (possibly
26 undefined) symbol and the operation used to combine the symbols,
27 and an (absolute) augend. RMS says this is so we can have 1-pass
28 assembly for any compiler emissions, and a 'case' statement might
29 emit 'undefined1 - undefined2'.
31 The type of an expression used to be stored as a segment. That got
32 confusing because it overloaded the concept of a segment. I added
33 an operator field, instead. */
35 /* This is the type of an expression. The operator types are also
36 used while parsing an expression.
38 NOTE: This enumeration must match the op_rank array in expr.c. */
42 /* An illegal expression. */
44 /* A nonexistent expression. */
46 /* X_add_number (a constant expression). */
48 /* X_add_symbol + X_add_number. */
50 /* X_add_symbol + X_add_number - the base address of the image. */
52 /* The section index of X_add_symbol. */
54 /* A register (X_add_number is register number). */
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
61 /* (- X_add_symbol) + X_add_number. */
63 /* (~ X_add_symbol) + X_add_number. */
65 /* (! X_add_symbol) + X_add_number. */
67 /* (X_add_symbol * X_op_symbol) + X_add_number. */
69 /* (X_add_symbol / X_op_symbol) + X_add_number. */
71 /* (X_add_symbol % X_op_symbol) + X_add_number. */
73 /* (X_add_symbol << X_op_symbol) + X_add_number. */
75 /* (X_add_symbol >> X_op_symbol) + X_add_number. */
77 /* (X_add_symbol | X_op_symbol) + X_add_number. */
79 /* (X_add_symbol |~ X_op_symbol) + X_add_number. */
81 /* (X_add_symbol ^ X_op_symbol) + X_add_number. */
83 /* (X_add_symbol & X_op_symbol) + X_add_number. */
85 /* (X_add_symbol + X_op_symbol) + X_add_number. */
87 /* (X_add_symbol - X_op_symbol) + X_add_number. */
89 /* (X_add_symbol == X_op_symbol) + X_add_number. */
91 /* (X_add_symbol != X_op_symbol) + X_add_number. */
93 /* (X_add_symbol < X_op_symbol) + X_add_number. */
95 /* (X_add_symbol <= X_op_symbol) + X_add_number. */
97 /* (X_add_symbol >= X_op_symbol) + X_add_number. */
99 /* (X_add_symbol > X_op_symbol) + X_add_number. */
101 /* (X_add_symbol && X_op_symbol) + X_add_number. */
103 /* (X_add_symbol || X_op_symbol) + X_add_number. */
105 /* X_op_symbol [ X_add_symbol ] */
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 */
116 typedef struct expressionS
118 /* The main symbol. */
119 symbolS
*X_add_symbol
;
120 /* The second symbol, if needed. */
121 symbolS
*X_op_symbol
;
122 /* A number to add. */
123 offsetT X_add_number
;
125 /* The type of the expression. We can't assume that an arbitrary
126 compiler can handle a bitfield of enum type. FIXME: We could
127 check this using autoconf. */
134 /* Non-zero if X_add_number should be regarded as unsigned. This is
135 only valid for O_constant expressions. It is only used when an
136 O_constant must be extended into a bignum (i.e., it is not used
137 when performing arithmetic on these values).
138 FIXME: This field is not set very reliably. */
139 unsigned int X_unsigned
: 1;
140 /* This is used to implement "word size + 1 bit" arithmetic, so that e.g.
141 expressions used with .sleb128 directives can use the full range available
142 for an unsigned word, but can also properly represent all values of a
144 unsigned int X_extrabit
: 1;
146 /* 7 additional bits can be defined if needed. */
148 /* Machine dependent field */
159 /* "result" should be type (expressionS *). */
160 #define expression(result) expr (0, result, expr_normal)
161 #define expression_and_evaluate(result) expr (0, result, expr_evaluate)
162 #define deferred_expression(result) expr (0, result, expr_defer)
164 /* If an expression is O_big, look here for its value. These common
165 data may be clobbered whenever expr() is called. */
166 /* Flonums returned here. Big enough to hold most precise flonum. */
167 extern FLONUM_TYPE generic_floating_point_number
;
168 /* Bignums returned here. */
169 extern LITTLENUM_TYPE generic_bignum
[];
170 /* Number of littlenums in above. */
171 #define SIZE_OF_LARGE_NUMBER (20)
173 typedef char operator_rankT
;
175 extern char get_symbol_name (char **);
176 extern char restore_line_pointer (char);
177 extern void expr_begin (void);
178 extern void expr_end (void);
179 extern void expr_set_precedence (void);
180 extern void expr_set_rank (operatorT
, operator_rankT
);
181 extern void add_to_result (expressionS
*, offsetT
, int);
182 extern void subtract_from_result (expressionS
*, offsetT
, int);
183 extern segT
expr (int, expressionS
*, enum expr_mode
);
184 extern unsigned int get_single_number (void);
185 extern symbolS
*make_expr_symbol (const expressionS
* expressionP
);
186 extern int expr_symbol_where (symbolS
*, const char **, unsigned int *);
187 extern void current_location (expressionS
*);
188 extern symbolS
*expr_build_uconstant (offsetT
);
189 extern symbolS
*expr_build_dot (void);
190 extern uint32_t generic_bignum_to_int32 (void);
191 extern uint64_t generic_bignum_to_int64 (void);
192 extern int resolve_expression (expressionS
*);
194 extern bool literal_prefix_dollar_hex
;