1 /* expr.h -> header file for expr.c
2 Copyright (C) 1987, 1992 Free Software Foundation, Inc.
4 This file is part of GAS, the GNU Assembler.
6 GAS is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GAS is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GAS; see the file COPYING. If not, write to
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
25 * Abbreviations (mnemonics).
33 * By popular demand, we define a struct to represent an expression.
34 * This will no doubt mutate as expressions become baroque.
36 * Currently, we support expressions like "foo-bar+42".
37 * In other words we permit a (possibly undefined) minuend, a
38 * (possibly undefined) subtrahend and an (absolute) augend.
39 * RMS says this is so we can have 1-pass assembly for any compiler
40 * emmissions, and a 'case' statement might emit 'undefined1 - undefined2'.
42 * To simplify table-driven dispatch, we also have a "segment" for the
43 * entire expression. That way we don't require complex reasoning about
44 * whether particular components are defined; and we can change component
45 * semantics without re-working all the dispatch tables in the assembler.
46 * In other words the "type" of an expression is its segment.
50 symbolS *X_add_symbol; /* foo */
51 symbolS *X_subtract_symbol; /* bar */
52 symbolS *X_got_symbol; /* got */
53 long X_add_number; /* 42. Must be signed. */
54 segT X_seg; /* What segment (expr type)? */
58 /* result should be type (expressionS *). */
59 #define expression(result) expr(0,result)
61 /* If an expression is SEG_BIG, look here */
62 /* for its value. These common data may */
63 /* be clobbered whenever expr() is called. */
64 extern FLONUM_TYPE generic_floating_point_number; /* Flonums returned here. */
65 /* Enough to hold most precise flonum. */
66 extern LITTLENUM_TYPE generic_bignum[]; /* Bignums returned here. */
67 #define SIZE_OF_LARGE_NUMBER (20) /* Number of littlenums in above. */
69 typedef char operator_rankT;
73 char get_symbol_end(void);
74 segT expr(int rank, expressionS *resultP);
75 unsigned int get_single_number(void);
77 #else /* not __STDC__ */
79 char get_symbol_end();
81 unsigned int get_single_number();
83 #endif /* not __STDC__ */