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comparison lwasm/expr.h @ 151:427e268e876b

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renamed src to lwasm to better reflect its purpose
author lost
date Fri, 30 Jan 2009 04:01:55 +0000
parents src/expr.h@718998b673ee
children
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150:f0881c115010 151:427e268e876b
1 /*
2 expr.h
3 Copyright © 2008 William Astle
4
5 This file is part of LWASM.
6
7 LWASM is free software: you can redistribute it and/or modify it under the
8 terms of the GNU General Public License as published by the Free Software
9 Foundation, either version 3 of the License, or (at your option) any later
10 version.
11
12 This program is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 more details.
16
17 You should have received a copy of the GNU General Public License along with
18 this program. If not, see <http://www.gnu.org/licenses/>.
19 */
20
21 /*
22 Definitions for expression evaluator
23 */
24
25 #ifndef __expr_h_seen__
26 #define __expr_h_seen__
27
28 #ifndef __expr_c_seen__
29 #define __expr_E__ extern
30 #else
31 #define __expr_E__
32 #endif
33
34 // term types
35 #define LWASM_TERM_NONE 0
36 #define LWASM_TERM_OPER 1 // an operator
37 #define LWASM_TERM_INT 2 // 32 bit signed integer
38 #define LWASM_TERM_SYM 3 // symbol reference
39 #define LWASM_TERM_SECBASE 4 // section base reference
40
41 // operator types
42 #define LWASM_OPER_NONE 0
43 #define LWASM_OPER_PLUS 1 // +
44 #define LWASM_OPER_MINUS 2 // -
45 #define LWASM_OPER_TIMES 3 // *
46 #define LWASM_OPER_DIVIDE 4 // /
47 #define LWASM_OPER_MOD 5 // %
48 #define LWASM_OPER_INTDIV 6 // \ (don't end line with \)
49 #define LWASM_OPER_BWAND 7 // bitwise AND
50 #define LWASM_OPER_BWOR 8 // bitwise OR
51 #define LWASM_OPER_BWXOR 9 // bitwise XOR
52 #define LWASM_OPER_AND 10 // boolean AND
53 #define LWASM_OPER_OR 11 // boolean OR
54 #define LWASM_OPER_NEG 12 // - unary negation (2's complement)
55 #define LWASM_OPER_COM 13 // ^ unary 1's complement
56
57
58 // term structure
59 typedef struct lwasm_expr_term_s
60 {
61 int term_type; // type of term (see above)
62 char *symbol; // name of a symbol
63 int value; // value of the term (int) or operator number (OPER)
64 } lwasm_expr_term_t;
65
66 // type for an expression evaluation stack
67 typedef struct lwasm_expr_stack_node_s lwasm_expr_stack_node_t;
68 struct lwasm_expr_stack_node_s
69 {
70 lwasm_expr_term_t *term;
71 lwasm_expr_stack_node_t *prev;
72 lwasm_expr_stack_node_t *next;
73 };
74
75 typedef struct lwasm_expr_stack_s
76 {
77 lwasm_expr_stack_node_t *head;
78 lwasm_expr_stack_node_t *tail;
79 } lwasm_expr_stack_t;
80
81 __expr_E__ void lwasm_expr_term_free(lwasm_expr_term_t *t);
82 __expr_E__ lwasm_expr_term_t *lwasm_expr_term_create_oper(int oper);
83 __expr_E__ lwasm_expr_term_t *lwasm_expr_term_create_sym(char *sym);
84 __expr_E__ lwasm_expr_term_t *lwasm_expr_term_create_int(int val);
85 __expr_E__ lwasm_expr_term_t *lwasm_expr_term_create_secbase(void);
86 __expr_E__ lwasm_expr_term_t *lwasm_expr_term_dup(lwasm_expr_term_t *t);
87
88 __expr_E__ void lwasm_expr_stack_free(lwasm_expr_stack_t *s);
89 __expr_E__ lwasm_expr_stack_t *lwasm_expr_stack_create(void);
90
91 __expr_E__ void lwasm_expr_stack_push(lwasm_expr_stack_t *s, lwasm_expr_term_t *t);
92 __expr_E__ lwasm_expr_term_t *lwasm_expr_stack_pop(lwasm_expr_stack_t *s);
93
94 /*
95 Evaluate an expression. The result is an lwasm_expr_stack_t pointer. If the
96 expression evaluates to a constant result, the stack will contain exactly one
97 value which will be a constant. Otherwise, the stack will contain the
98 expression with all operations that can be evaluated completely evaluated.
99 You must call lwasm_expr_stack_free() on the result when you are finished
100 with it.
101 */
102 __expr_E__ lwasm_expr_stack_t *lwasm_expr_eval(const char *inp, const char **outp, lwasm_expr_stack_t *(*sfunc)(char *sym, void *state), void *state);
103
104 // simplify expression
105 __expr_E__ int lwasm_expr_reval(lwasm_expr_stack_t *s, lwasm_expr_stack_t *(*sfunc)(char *sym, void *state), void *state);
106
107 // useful macros
108 // is the expression "simple" (one term)?
109 #define lwasm_expr_is_simple(s) ((s) -> head == (s) -> tail)
110
111 // is the expression constant?
112 #define lwasm_expr_is_constant(s) (lwasm_expr_is_simple(s) && (!((s) -> head) || (s) -> head -> term -> term_type == LWASM_TERM_INT))
113
114 // get the constant value of an expression or 0 if not constant
115 #define lwasm_expr_get_value(s) (lwasm_expr_is_constant(s) ? ((s) -> head ? (s) -> head -> term -> value : 0) : 0)
116
117 #undef __expr_E__
118
119 #endif // __expr_h_seen__