/* expr.h -> header file for expr.c
- Copyright (C) 1987 Free Software Foundation, Inc.
+ Copyright (C) 1987, 1992, 1993 Free Software Foundation, Inc.
-This file is part of GAS, the GNU Assembler.
+ This file is part of GAS, the GNU Assembler.
-GAS is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 1, or (at your option)
-any later version.
+ GAS is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
-GAS is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
+ GAS is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
-You should have received a copy of the GNU General Public License
-along with GAS; see the file COPYING. If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
-
-/*
- * Abbreviations (mnemonics).
- *
- * O operator
- * Q quantity, operand
- * X eXpression
- */
+ You should have received a copy of the GNU General Public License
+ along with GAS; see the file COPYING. If not, write to
+ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/*
* By popular demand, we define a struct to represent an expression.
* This will no doubt mutate as expressions become baroque.
*
- * Currently, we support expressions like "foo-bar+42".
- * In other words we permit a (possibly undefined) minuend, a
- * (possibly undefined) subtrahend and an (absolute) augend.
- * RMS says this is so we can have 1-pass assembly for any compiler
- * emmissions, and a 'case' statement might emit 'undefined1 - undefined2'.
+ * Currently, we support expressions like "foo OP bar + 42". In other
+ * words we permit a (possibly undefined) symbol, a (possibly
+ * undefined) symbol and the operation used to combine the symbols,
+ * and an (absolute) augend. RMS says this is so we can have 1-pass
+ * assembly for any compiler emissions, and a 'case' statement might
+ * emit 'undefined1 - undefined2'.
*
- * To simplify table-driven dispatch, we also have a "segment" for the
- * entire expression. That way we don't require complex reasoning about
- * whether particular components are defined; and we can change component
- * semantics without re-working all the dispatch tables in the assembler.
- * In other words the "type" of an expression is its segment.
+ * The type of an expression used to be stored as a segment. That got
+ * confusing because it overloaded the concept of a segment. I added
+ * an operator field, instead.
*/
-typedef struct
-{
- symbolS *X_add_symbol; /* foo */
- symbolS *X_subtract_symbol; /* bar */
- long X_add_number; /* 42. Must be signed. */
- segT X_seg; /* What segment (expr type)? */
-}
-expressionS;
+/* This is the type of an expression. The operator types are also
+ used while parsing an expression.
- /* result should be type (expressionS *). */
-#define expression(result) expr(0,result)
+ NOTE: This enumeration must match the op_rank array in expr.c. */
- /* If an expression is SEG_BIG, look here */
- /* for its value. These common data may */
- /* be clobbered whenever expr() is called. */
-extern FLONUM_TYPE generic_floating_point_number; /* Flonums returned here. */
- /* Enough to hold most precise flonum. */
-extern LITTLENUM_TYPE generic_bignum []; /* Bignums returned here. */
-#define SIZE_OF_LARGE_NUMBER (20) /* Number of littlenums in above. */
+typedef enum
+{
+ /* An illegal expression. */
+ O_illegal,
+ /* A nonexistent expression. */
+ O_absent,
+ /* X_add_number (a constant expression). */
+ O_constant,
+ /* X_add_symbol + X_add_number. */
+ O_symbol,
+ /* A register (X_add_number is register number). */
+ O_register,
+ /* A big value. If X_add_number is negative or 0, the value is in
+ generic_floating_point_number. Otherwise the value is in
+ generic_bignum, and X_add_number is the number of LITTLENUMs in
+ the value. */
+ O_big,
+ /* (- X_add_symbol) + X_add_number. */
+ O_uminus,
+ /* (~ X_add_symbol) + X_add_number. */
+ O_bit_not,
+ /* (X_add_symbol * X_op_symbol) + X_add_number. */
+ O_multiply,
+ /* (X_add_symbol / X_op_symbol) + X_add_number. */
+ O_divide,
+ /* X_add_symbol % X_op_symbol) + X_add_number. */
+ O_modulus,
+ /* X_add_symbol << X_op_symbol) + X_add_number. */
+ O_left_shift,
+ /* X_add_symbol >> X_op_symbol) + X_add_number. */
+ O_right_shift,
+ /* X_add_symbol | X_op_symbol) + X_add_number. */
+ O_bit_inclusive_or,
+ /* X_add_symbol |~ X_op_symbol) + X_add_number. */
+ O_bit_or_not,
+ /* X_add_symbol ^ X_op_symbol) + X_add_number. */
+ O_bit_exclusive_or,
+ /* X_add_symbol & X_op_symbol) + X_add_number. */
+ O_bit_and,
+ /* X_add_symbol + X_op_symbol) + X_add_number. */
+ O_add,
+ /* X_add_symbol - X_op_symbol) + X_add_number. */
+ O_subtract
+} operatorT;
+
+typedef struct expressionS
+{
+ /* The type of the expression. */
+ operatorT X_op;
+ /* The main symbol. */
+ struct symbol *X_add_symbol;
+ /* The second symbol, if needed. */
+ struct symbol *X_op_symbol;
+ /* A number to add. */
+ offsetT X_add_number;
+ /* Non-zero if X_add_number should be regarded as unsigned. This is
+ only valid for O_constant expressions. It is only used when an
+ O_constant must be extended into a bignum (i.e., it is not used
+ when performing arithmetic on these values).
+ FIXME: This field is not set very reliably.
+ If we ever need more flags here, we can make them bitfields. */
+ int X_unsigned;
+} expressionS;
+
+/* "result" should be type (expressionS *). */
+#define expression(result) expr (0, result)
+
+/* If an expression is O_big, look here for its value. These common
+ data may be clobbered whenever expr() is called. */
+/* Flonums returned here. Big enough to hold most precise flonum. */
+extern FLONUM_TYPE generic_floating_point_number;
+/* Bignums returned here. */
+extern LITTLENUM_TYPE generic_bignum[];
+/* Number of littlenums in above. */
+#define SIZE_OF_LARGE_NUMBER (20)
typedef char operator_rankT;
-#ifdef __STDC__
-
-char get_symbol_end(void);
-segT expr(int rank, expressionS *resultP);
-
-#else /* __STDC__ */
-
-char get_symbol_end();
-segT expr();
-
-#endif /* __STDC__ */
+char get_symbol_end PARAMS ((void));
+segT expr PARAMS ((int rank, expressionS * resultP));
+unsigned int get_single_number PARAMS ((void));
+symbolS *make_expr_symbol PARAMS ((expressionS * expressionP));
-/* end: expr.h */
+/* end of expr.h */
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