(cur_mach): New static local.

[deliverable/binutils-gdb.git] / gas / expr.h

diff --git a/gas/expr.h b/gas/expr.h
index 899ac0ae838ead2f951c58985657f0f386e6f7b7..c7b97da429464d426eea979c00b2bb49fd94cf31 100644 (file)
--- a/gas/expr.h
+++ b/gas/expr.h
@@ -1,5 +1,5 @@
 /* expr.h -> header file for expr.c
-   Copyright (C) 1987, 1992 Free Software Foundation, Inc.
+   Copyright (C) 1987, 1992, 1993 Free Software Foundation, Inc.
 
    This file is part of GAS, the GNU Assembler.
 
@@ -17,46 +17,95 @@
    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
- */
-
 /*
  * 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
- * emissions, 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
+/* This is the type of an expression.  The operator types are also
+   used while parsing an expression.
+
+   NOTE: This enumeration must match the op_rank array in expr.c.  */
+
+typedef enum
 {
-  symbolS *X_add_symbol;       /* "foo", above */
-  symbolS *X_subtract_symbol;  /* "bar", above */
-  offsetT X_add_number;                /* 42, above -- must be signed */
-  /* What segment (expr type)? */
-  segT X_seg;
-}
+  /* 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;
 
-expressionS;
+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)
+#define expression(result) expr (0, result)
 
-/* If an expression is SEG_BIG, look here for its value. These common
+/* 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;
@@ -70,5 +119,6 @@ typedef char operator_rankT;
 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 of expr.h */