aboutsummaryrefslogtreecommitdiff
path: root/gas/expr.h
diff options
context:
space:
mode:
Diffstat (limited to 'gas/expr.h')
-rw-r--r--gas/expr.h79
1 files changed, 79 insertions, 0 deletions
diff --git a/gas/expr.h b/gas/expr.h
new file mode 100644
index 0000000..350215e
--- /dev/null
+++ b/gas/expr.h
@@ -0,0 +1,79 @@
+/* expr.h -> header file for expr.c
+ Copyright (C) 1987 Free Software Foundation, Inc.
+
+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 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
+ */
+
+/*
+ * 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'.
+ *
+ * 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.
+ */
+
+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;
+
+ /* result should be type (expressionS *). */
+#define expression(result) expr(0,result)
+
+ /* 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 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__ */
+
+/* end: expr.h */