1 /* expr.h -> header file for expr.c 2 Copyright 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 3 2002, 2003 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, 51 Franklin Street - Fifth Floor, Boston, MA 20 02110-1301, 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 43 typedef 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; 115 116 typedef 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 enum expr_mode 147 { 148 expr_evaluate, 149 expr_normal, 150 expr_defer 151 }; 152 153 /* "result" should be type (expressionS *). */ 154 #define expression(result) expr (0, result, expr_normal) 155 #define expression_and_evaluate(result) expr (0, result, expr_evaluate) 156 #define deferred_expression(result) expr (0, result, expr_defer) 157 158 /* If an expression is O_big, look here for its value. These common 159 data may be clobbered whenever expr() is called. */ 160 /* Flonums returned here. Big enough to hold most precise flonum. */ 161 extern FLONUM_TYPE generic_floating_point_number; 162 /* Bignums returned here. */ 163 extern LITTLENUM_TYPE generic_bignum[]; 164 /* Number of littlenums in above. */ 165 #define SIZE_OF_LARGE_NUMBER (20) 166 167 typedef char operator_rankT; 168 169 extern char get_symbol_end (void); 170 extern void expr_begin (void); 171 extern void expr_set_precedence (void); 172 extern segT expr (int, expressionS *, enum expr_mode); 173 extern unsigned int get_single_number (void); 174 extern symbolS *make_expr_symbol (expressionS * expressionP); 175 extern int expr_symbol_where (symbolS *, char **, unsigned int *); 176 177 extern symbolS *expr_build_uconstant (offsetT); 178 extern symbolS *expr_build_dot (void); 179 180 int resolve_expression (expressionS *); 181