expr.h revision 78828
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 /* this must be the largest value */ 111 O_max 112} operatorT; 113 114typedef struct expressionS { 115 /* The main symbol. */ 116 symbolS *X_add_symbol; 117 /* The second symbol, if needed. */ 118 symbolS *X_op_symbol; 119 /* A number to add. */ 120 offsetT X_add_number; 121 122 /* The type of the expression. We can't assume that an arbitrary 123 compiler can handle a bitfield of enum type. FIXME: We could 124 check this using autoconf. */ 125#ifdef __GNUC__ 126 operatorT X_op : 8; 127#else 128 unsigned char X_op; 129#endif 130 131 /* Non-zero if X_add_number should be regarded as unsigned. This is 132 only valid for O_constant expressions. It is only used when an 133 O_constant must be extended into a bignum (i.e., it is not used 134 when performing arithmetic on these values). 135 FIXME: This field is not set very reliably. */ 136 unsigned int X_unsigned : 1; 137 138 /* 7 additional bits can be defined if needed. */ 139 140 /* Machine dependent field */ 141 unsigned short X_md; 142} expressionS; 143 144/* "result" should be type (expressionS *). */ 145#define expression(result) expr (0, result) 146 147/* If an expression is O_big, look here for its value. These common 148 data may be clobbered whenever expr() is called. */ 149/* Flonums returned here. Big enough to hold most precise flonum. */ 150extern FLONUM_TYPE generic_floating_point_number; 151/* Bignums returned here. */ 152extern LITTLENUM_TYPE generic_bignum[]; 153/* Number of littlenums in above. */ 154#define SIZE_OF_LARGE_NUMBER (20) 155 156typedef char operator_rankT; 157 158extern char get_symbol_end PARAMS ((void)); 159extern void expr_begin PARAMS ((void)); 160extern void expr_set_precedence PARAMS ((void)); 161extern segT expr PARAMS ((int rank, expressionS * resultP)); 162extern unsigned int get_single_number PARAMS ((void)); 163extern symbolS *make_expr_symbol PARAMS ((expressionS * expressionP)); 164extern int expr_symbol_where 165 PARAMS ((symbolS *, char **, unsigned int *)); 166 167extern symbolS *expr_build_uconstant PARAMS ((offsetT)); 168extern symbolS *expr_build_unary PARAMS ((operatorT, symbolS *)); 169extern symbolS *expr_build_binary PARAMS ((operatorT, symbolS *, symbolS *)); 170extern symbolS *expr_build_dot PARAMS ((void)); 171