1 /* expr.h -> header file for expr.c 2 Copyright (C) 1987-2026 Free Software Foundation, Inc. 3 4 This file is part of GAS, the GNU Assembler. 5 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) 9 any later version. 10 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. 15 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 19 02110-1301, USA. */ 20 21 /* By popular demand, we define a struct to represent an expression. 22 This will no doubt mutate as expressions become baroque. 23 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'. 30 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. */ 34 35 /* This is the type of an expression. The operator types are also 36 used while parsing an expression. 37 38 NOTE: This enumeration must match the op_rank array in expr.c. */ 39 40 typedef enum operatorT 41 { 42 /* An illegal expression. */ 43 O_illegal, 44 /* A nonexistent expression. */ 45 O_absent, 46 /* X_add_number (a constant expression). */ 47 O_constant, 48 /* X_add_symbol + X_add_number. */ 49 O_symbol, 50 /* X_add_symbol + X_add_number - the base address of the image. */ 51 O_symbol_rva, 52 /* The section index of X_add_symbol. */ 53 O_secidx, 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; 115 116 typedef struct expressionS 117 { 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; 124 125 /* The type of the expression. */ 126 ENUM_BITFIELD (operatorT) X_op : 8; 127 128 /* Non-zero if the expression value should be regarded as unsigned. This is 129 only valid for 130 - O_constant expressions, where it is only used when an O_constant must be 131 extended into a bignum (i.e., it is not used when performing arithmetic 132 on these values), 133 - O_big integer expressions, i.e. when X_add_number is positive. 134 FIXME: This field is not set very reliably. */ 135 unsigned int X_unsigned : 1; 136 /* This is used to implement "word size + 1 bit" arithmetic, so that e.g. 137 expressions used with .sleb128 directives can use the full range available 138 for an unsigned word, but can also properly represent all values of a 139 signed word. */ 140 unsigned int X_extrabit : 1; 141 142 /* Machine dependent field. */ 143 unsigned short X_md; 144 } expressionS; 145 146 enum expr_mode 147 { 148 expr_evaluate, 149 expr_normal, 150 expr_defer, 151 expr_defer_incl_dot, 152 }; 153 154 #define expr_defer_p(m) ((m) >= expr_defer) 155 156 /* "result" should be type (expressionS *). */ 157 #define expression(result) expr (0, result, expr_normal) 158 #define expression_and_evaluate(result) expr (0, result, expr_evaluate) 159 #define deferred_expression(result) expr (0, result, expr_defer) 160 161 /* If an expression is O_big, look here for its value. These common 162 data may be clobbered whenever expr() is called. */ 163 /* Flonums returned here. Big enough to hold most precise flonum. */ 164 extern FLONUM_TYPE generic_floating_point_number; 165 /* Bignums returned here. */ 166 extern LITTLENUM_TYPE generic_bignum[]; 167 /* Number of littlenums in above. */ 168 #define SIZE_OF_LARGE_NUMBER (20) 169 170 typedef char operator_rankT; 171 172 extern char get_symbol_name (char **); 173 extern char restore_line_pointer (char); 174 extern void expr_begin (void); 175 extern void expr_end (void); 176 extern void expr_set_precedence (void); 177 extern void expr_set_rank (operatorT, operator_rankT); 178 extern void add_to_result (expressionS *, offsetT, int); 179 extern void subtract_from_result (expressionS *, offsetT, int); 180 extern segT expr (int, expressionS *, enum expr_mode); 181 extern unsigned int get_single_number (void); 182 extern symbolS *make_expr_symbol (const expressionS * expressionP); 183 extern int expr_symbol_where (symbolS *, const char **, unsigned int *); 184 extern void current_location (expressionS *, enum expr_mode); 185 extern symbolS *expr_build_uconstant (offsetT); 186 extern symbolS *expr_build_dot (void); 187 extern uint32_t generic_bignum_to_int32 (void); 188 extern uint64_t generic_bignum_to_int64 (void); 189 extern int resolve_expression (expressionS *); 190 extern void resolve_register (expressionS *); 191 192 extern bool literal_prefix_dollar_hex; 193
Indexes created Tue Feb 24 08:35:24 UTC 2026