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Diffstat (limited to 'gas/expr.h')
-rw-r--r-- | gas/expr.h | 79 |
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 */ |