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