![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to db_expr.c CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [Net/2] / Net2 / ddb|
Return to db_expr.c CVS log | Up to [Net/2] / Net2 / ddb |
1.1 root 1: /*
2: * Mach Operating System
3: * Copyright (c) 1991,1990 Carnegie Mellon University
4: * All Rights Reserved.
5: *
6: * Permission to use, copy, modify and distribute this software and its
7: * documentation is hereby granted, provided that both the copyright
8: * notice and this permission notice appear in all copies of the
9: * software, derivative works or modified versions, and any portions
10: * thereof, and that both notices appear in supporting documentation.
11: *
12: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14: * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15: *
16: * Carnegie Mellon requests users of this software to return to
17: *
18: * Software Distribution Coordinator or [email protected]
19: * School of Computer Science
20: * Carnegie Mellon University
21: * Pittsburgh PA 15213-3890
22: *
23: * any improvements or extensions that they make and grant Carnegie the
24: * rights to redistribute these changes.
25: */
26: /*
27: * HISTORY
28: * $Log: db_expr.c,v $
1.1.1.2 ! root 29: * Revision 1.1.1.1 1993/03/21 09:46:26 cgd
! 30: * initial import of 386bsd-0.1 sources
! 31: *
1.1 root 32: * Revision 1.1 1992/03/25 21:45:09 pace
33: * Initial revision
34: *
35: * Revision 2.3 91/02/05 17:06:25 mrt
36: * Changed to new Mach copyright
37: * [91/01/31 16:17:46 mrt]
38: *
39: * Revision 2.2 90/08/27 21:50:57 dbg
40: * Use '..' instead of '$$' for db_prev.
41: * Use '+' for db_next.
42: * [90/08/22 dbg]
43: *
44: * Allow repeated unary operators.
45: * [90/08/20 dbg]
46: *
47: * Reflected back rename of db_symbol_value->db_value_of_name
48: * [90/08/20 af]
49: * Reduce lint.
50: * [90/08/07 dbg]
51: * Created.
52: * [90/07/25 dbg]
53: *
54: */
55: /*
56: * Author: David B. Golub, Carnegie Mellon University
57: * Date: 7/90
58: */
59: #include "param.h"
60: #include "proc.h"
61: #include <machine/db_machdep.h>
62: #include <ddb/db_lex.h>
63: #include <ddb/db_access.h>
64: #include <ddb/db_command.h>
65:
66: boolean_t
67: db_term(valuep)
68: db_expr_t *valuep;
69: {
70: int t;
71:
72: t = db_read_token();
73: if (t == tIDENT) {
74: if (!db_value_of_name(db_tok_string, valuep)) {
75: db_error("Symbol not found\n");
76: /*NOTREACHED*/
77: }
78: return (TRUE);
79: }
80: if (t == tNUMBER) {
81: *valuep = (db_expr_t)db_tok_number;
82: return (TRUE);
83: }
84: if (t == tDOT) {
85: *valuep = (db_expr_t)db_dot;
86: return (TRUE);
87: }
88: if (t == tDOTDOT) {
89: *valuep = (db_expr_t)db_prev;
90: return (TRUE);
91: }
92: if (t == tPLUS) {
93: *valuep = (db_expr_t) db_next;
94: return (TRUE);
95: }
96: if (t == tDITTO) {
97: *valuep = (db_expr_t)db_last_addr;
98: return (TRUE);
99: }
100: if (t == tDOLLAR) {
101: if (!db_get_variable(valuep))
102: return (FALSE);
103: return (TRUE);
104: }
105: if (t == tLPAREN) {
106: if (!db_expression(valuep)) {
107: db_error("Syntax error\n");
108: /*NOTREACHED*/
109: }
110: t = db_read_token();
111: if (t != tRPAREN) {
112: db_error("Syntax error\n");
113: /*NOTREACHED*/
114: }
115: return (TRUE);
116: }
117: db_unread_token(t);
118: return (FALSE);
119: }
120:
121: boolean_t
122: db_unary(valuep)
123: db_expr_t *valuep;
124: {
125: int t;
126:
127: t = db_read_token();
128: if (t == tMINUS) {
129: if (!db_unary(valuep)) {
130: db_error("Syntax error\n");
131: /*NOTREACHED*/
132: }
133: *valuep = -*valuep;
134: return (TRUE);
135: }
136: if (t == tSTAR) {
137: /* indirection */
138: if (!db_unary(valuep)) {
139: db_error("Syntax error\n");
140: /*NOTREACHED*/
141: }
142: *valuep = db_get_value((db_addr_t)*valuep, sizeof(int), FALSE);
143: return (TRUE);
144: }
145: db_unread_token(t);
146: return (db_term(valuep));
147: }
148:
149: boolean_t
150: db_mult_expr(valuep)
151: db_expr_t *valuep;
152: {
153: db_expr_t lhs, rhs;
154: int t;
155:
156: if (!db_unary(&lhs))
157: return (FALSE);
158:
159: t = db_read_token();
160: while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) {
161: if (!db_term(&rhs)) {
162: db_error("Syntax error\n");
163: /*NOTREACHED*/
164: }
165: if (t == tSTAR)
166: lhs *= rhs;
167: else {
168: if (rhs == 0) {
169: db_error("Divide by 0\n");
170: /*NOTREACHED*/
171: }
172: if (t == tSLASH)
173: lhs /= rhs;
174: else if (t == tPCT)
175: lhs %= rhs;
176: else
177: lhs = ((lhs+rhs-1)/rhs)*rhs;
178: }
179: t = db_read_token();
180: }
181: db_unread_token(t);
182: *valuep = lhs;
183: return (TRUE);
184: }
185:
186: boolean_t
187: db_add_expr(valuep)
188: db_expr_t *valuep;
189: {
190: db_expr_t lhs, rhs;
191: int t;
192:
193: if (!db_mult_expr(&lhs))
194: return (FALSE);
195:
196: t = db_read_token();
197: while (t == tPLUS || t == tMINUS) {
198: if (!db_mult_expr(&rhs)) {
199: db_error("Syntax error\n");
200: /*NOTREACHED*/
201: }
202: if (t == tPLUS)
203: lhs += rhs;
204: else
205: lhs -= rhs;
206: t = db_read_token();
207: }
208: db_unread_token(t);
209: *valuep = lhs;
210: return (TRUE);
211: }
212:
213: boolean_t
214: db_shift_expr(valuep)
215: db_expr_t *valuep;
216: {
217: db_expr_t lhs, rhs;
218: int t;
219:
220: if (!db_add_expr(&lhs))
221: return (FALSE);
222:
223: t = db_read_token();
224: while (t == tSHIFT_L || t == tSHIFT_R) {
225: if (!db_add_expr(&rhs)) {
226: db_error("Syntax error\n");
227: /*NOTREACHED*/
228: }
229: if (rhs < 0) {
230: db_error("Negative shift amount\n");
231: /*NOTREACHED*/
232: }
233: if (t == tSHIFT_L)
234: lhs <<= rhs;
235: else {
236: /* Shift right is unsigned */
237: lhs = (unsigned) lhs >> rhs;
238: }
239: t = db_read_token();
240: }
241: db_unread_token(t);
242: *valuep = lhs;
243: return (TRUE);
244: }
245:
246: int
247: db_expression(valuep)
248: db_expr_t *valuep;
249: {
250: return (db_shift_expr(valuep));
251: }
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.