1/*	$NetBSD: db_expr.c,v 1.15 2007/02/22 06:41:01 thorpej Exp $	*/
2
3/*
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
15 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
21 *  School of Computer Science
22 *  Carnegie Mellon University
23 *  Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 *
28 *	Author: David B. Golub, Carnegie Mellon University
29 *	Date:	7/90
30 */
31
32#include <sys/cdefs.h>
33__KERNEL_RCSID(0, "$NetBSD: db_expr.c,v 1.15 2007/02/22 06:41:01 thorpej Exp $");
34
35#include <sys/param.h>
36#include <sys/proc.h>
37
38#include <ddb/ddb.h>
39
40static bool db_term(db_expr_t *);
41static bool db_unary(db_expr_t *);
42static bool db_mult_expr(db_expr_t *);
43static bool db_add_expr(db_expr_t *);
44static bool db_shift_expr(db_expr_t *);
45
46static bool
47db_term(db_expr_t *valuep)
48{
49	int	t;
50
51	t = db_read_token();
52	if (t == tIDENT) {
53		if (!db_value_of_name(db_tok_string, valuep)) {
54			db_expr_t v = 0;
55			int	i, c, byte;
56
57			/* See if we can make a number out of all of it */
58			for (i = 0; (c = db_tok_string[i]) != '\0'; i++) {
59				byte = 0;
60				if (c >= '0' && c <= '9')
61					byte = c - '0';
62				else if (db_radix == 16 && c >= 'a' && c <= 'f')
63					byte = c - 'a' + 10;
64				else if (db_radix == 16 && c >= 'A' && c <= 'F')
65					byte = c - 'A' + 10;
66				else
67					db_error("Symbol not found\n");
68					/*NOTREACHED*/
69				v = v * db_radix + byte;
70			}
71			*valuep = (db_expr_t)v;
72		}
73		return (true);
74	}
75	if (t == tNUMBER) {
76		*valuep = (db_expr_t)db_tok_number;
77		return (true);
78	}
79	if (t == tDOT) {
80		*valuep = (db_expr_t)db_dot;
81		return (true);
82	}
83	if (t == tDOTDOT) {
84		*valuep = (db_expr_t)db_prev;
85		return (true);
86	}
87	if (t == tPLUS) {
88		*valuep = (db_expr_t) db_next;
89		return (true);
90	}
91	if (t == tDITTO) {
92		*valuep = (db_expr_t)db_last_addr;
93		return (true);
94	}
95	if (t == tDOLLAR) {
96		if (!db_get_variable(valuep))
97		    return (false);
98		return (true);
99	}
100	if (t == tLPAREN) {
101		if (!db_expression(valuep)) {
102			db_error("Syntax error\n");
103			/*NOTREACHED*/
104		}
105		t = db_read_token();
106		if (t != tRPAREN) {
107			db_error("Syntax error\n");
108			/*NOTREACHED*/
109		}
110		return (true);
111	}
112	db_unread_token(t);
113	return (false);
114}
115
116static bool
117db_unary(db_expr_t *valuep)
118{
119	int	t;
120
121	t = db_read_token();
122	if (t == tMINUS) {
123		if (!db_unary(valuep)) {
124			db_error("Syntax error\n");
125			/*NOTREACHED*/
126		}
127		*valuep = -*valuep;
128		return (true);
129	}
130	if (t == tSTAR) {
131		/* indirection */
132		if (!db_unary(valuep)) {
133			db_error("Syntax error\n");
134			/*NOTREACHED*/
135		}
136		*valuep = db_get_value((db_addr_t)*valuep, sizeof(db_expr_t),
137		    false);
138		return (true);
139	}
140	db_unread_token(t);
141	return (db_term(valuep));
142}
143
144static bool
145db_mult_expr(db_expr_t *valuep)
146{
147	db_expr_t	lhs, rhs;
148	int		t;
149
150	if (!db_unary(&lhs))
151		return (false);
152
153	t = db_read_token();
154	while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) {
155		if (!db_term(&rhs)) {
156			db_error("Syntax error\n");
157			/*NOTREACHED*/
158		}
159		if (t == tSTAR)
160			lhs *= rhs;
161		else {
162			if (rhs == 0) {
163				db_error("Divide by 0\n");
164				/*NOTREACHED*/
165			}
166			if (t == tSLASH)
167				lhs /= rhs;
168			else if (t == tPCT)
169				lhs %= rhs;
170			else
171				lhs = ((lhs+rhs-1)/rhs)*rhs;
172		}
173		t = db_read_token();
174	}
175	db_unread_token(t);
176	*valuep = lhs;
177	return (true);
178}
179
180static bool
181db_add_expr(db_expr_t *valuep)
182{
183	db_expr_t	lhs, rhs;
184	int		t;
185
186	if (!db_mult_expr(&lhs))
187		return (false);
188
189	t = db_read_token();
190	while (t == tPLUS || t == tMINUS) {
191		if (!db_mult_expr(&rhs)) {
192			db_error("Syntax error\n");
193			/*NOTREACHED*/
194		}
195		if (t == tPLUS)
196			lhs += rhs;
197		else
198			lhs -= rhs;
199		t = db_read_token();
200	}
201	db_unread_token(t);
202	*valuep = lhs;
203	return (true);
204}
205
206static bool
207db_shift_expr(db_expr_t *valuep)
208{
209	db_expr_t	lhs, rhs;
210	int		t;
211
212	if (!db_add_expr(&lhs))
213		return (false);
214
215	t = db_read_token();
216	while (t == tSHIFT_L || t == tSHIFT_R) {
217		if (!db_add_expr(&rhs)) {
218			db_error("Syntax error\n");
219			/*NOTREACHED*/
220		}
221		if (rhs < 0) {
222			db_error("Negative shift amount\n");
223			/*NOTREACHED*/
224		}
225		if (t == tSHIFT_L)
226			lhs <<= rhs;
227		else {
228			/* Shift right is unsigned */
229			lhs = (unsigned long) lhs >> rhs;
230		}
231		t = db_read_token();
232	}
233	db_unread_token(t);
234	*valuep = lhs;
235	return (true);
236}
237
238int
239db_expression(db_expr_t *valuep)
240{
241
242	return (db_shift_expr(valuep));
243}
244