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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: /*
1.1.1.3 ! root 27: * db_expr.c,v 1.2 1993/05/20 03:39:13 cgd Exp
! 28: *
1.1 root 29: * HISTORY
1.1.1.3 ! root 30: * db_expr.c,v
! 31: * Revision 1.2 1993/05/20 03:39:13 cgd
! 32: * add explicit rcs id
! 33: *
! 34: * Revision 1.1.1.1 1993/03/21 09:46:26 cgd
1.1.1.2 root 35: * initial import of 386bsd-0.1 sources
36: *
1.1 root 37: * Revision 1.1 1992/03/25 21:45:09 pace
38: * Initial revision
39: *
40: * Revision 2.3 91/02/05 17:06:25 mrt
41: * Changed to new Mach copyright
42: * [91/01/31 16:17:46 mrt]
43: *
44: * Revision 2.2 90/08/27 21:50:57 dbg
45: * Use '..' instead of '$$' for db_prev.
46: * Use '+' for db_next.
47: * [90/08/22 dbg]
48: *
49: * Allow repeated unary operators.
50: * [90/08/20 dbg]
51: *
52: * Reflected back rename of db_symbol_value->db_value_of_name
53: * [90/08/20 af]
54: * Reduce lint.
55: * [90/08/07 dbg]
56: * Created.
57: * [90/07/25 dbg]
58: *
59: */
60: /*
61: * Author: David B. Golub, Carnegie Mellon University
62: * Date: 7/90
63: */
64: #include "param.h"
65: #include "proc.h"
66: #include <machine/db_machdep.h>
67: #include <ddb/db_lex.h>
68: #include <ddb/db_access.h>
69: #include <ddb/db_command.h>
70:
71: boolean_t
72: db_term(valuep)
73: db_expr_t *valuep;
74: {
75: int t;
76:
77: t = db_read_token();
78: if (t == tIDENT) {
79: if (!db_value_of_name(db_tok_string, valuep)) {
80: db_error("Symbol not found\n");
81: /*NOTREACHED*/
82: }
83: return (TRUE);
84: }
85: if (t == tNUMBER) {
86: *valuep = (db_expr_t)db_tok_number;
87: return (TRUE);
88: }
89: if (t == tDOT) {
90: *valuep = (db_expr_t)db_dot;
91: return (TRUE);
92: }
93: if (t == tDOTDOT) {
94: *valuep = (db_expr_t)db_prev;
95: return (TRUE);
96: }
97: if (t == tPLUS) {
98: *valuep = (db_expr_t) db_next;
99: return (TRUE);
100: }
101: if (t == tDITTO) {
102: *valuep = (db_expr_t)db_last_addr;
103: return (TRUE);
104: }
105: if (t == tDOLLAR) {
106: if (!db_get_variable(valuep))
107: return (FALSE);
108: return (TRUE);
109: }
110: if (t == tLPAREN) {
111: if (!db_expression(valuep)) {
112: db_error("Syntax error\n");
113: /*NOTREACHED*/
114: }
115: t = db_read_token();
116: if (t != tRPAREN) {
117: db_error("Syntax error\n");
118: /*NOTREACHED*/
119: }
120: return (TRUE);
121: }
122: db_unread_token(t);
123: return (FALSE);
124: }
125:
126: boolean_t
127: db_unary(valuep)
128: db_expr_t *valuep;
129: {
130: int t;
131:
132: t = db_read_token();
133: if (t == tMINUS) {
134: if (!db_unary(valuep)) {
135: db_error("Syntax error\n");
136: /*NOTREACHED*/
137: }
138: *valuep = -*valuep;
139: return (TRUE);
140: }
141: if (t == tSTAR) {
142: /* indirection */
143: if (!db_unary(valuep)) {
144: db_error("Syntax error\n");
145: /*NOTREACHED*/
146: }
147: *valuep = db_get_value((db_addr_t)*valuep, sizeof(int), FALSE);
148: return (TRUE);
149: }
150: db_unread_token(t);
151: return (db_term(valuep));
152: }
153:
154: boolean_t
155: db_mult_expr(valuep)
156: db_expr_t *valuep;
157: {
158: db_expr_t lhs, rhs;
159: int t;
160:
161: if (!db_unary(&lhs))
162: return (FALSE);
163:
164: t = db_read_token();
165: while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) {
166: if (!db_term(&rhs)) {
167: db_error("Syntax error\n");
168: /*NOTREACHED*/
169: }
170: if (t == tSTAR)
171: lhs *= rhs;
172: else {
173: if (rhs == 0) {
174: db_error("Divide by 0\n");
175: /*NOTREACHED*/
176: }
177: if (t == tSLASH)
178: lhs /= rhs;
179: else if (t == tPCT)
180: lhs %= rhs;
181: else
182: lhs = ((lhs+rhs-1)/rhs)*rhs;
183: }
184: t = db_read_token();
185: }
186: db_unread_token(t);
187: *valuep = lhs;
188: return (TRUE);
189: }
190:
191: boolean_t
192: db_add_expr(valuep)
193: db_expr_t *valuep;
194: {
195: db_expr_t lhs, rhs;
196: int t;
197:
198: if (!db_mult_expr(&lhs))
199: return (FALSE);
200:
201: t = db_read_token();
202: while (t == tPLUS || t == tMINUS) {
203: if (!db_mult_expr(&rhs)) {
204: db_error("Syntax error\n");
205: /*NOTREACHED*/
206: }
207: if (t == tPLUS)
208: lhs += rhs;
209: else
210: lhs -= rhs;
211: t = db_read_token();
212: }
213: db_unread_token(t);
214: *valuep = lhs;
215: return (TRUE);
216: }
217:
218: boolean_t
219: db_shift_expr(valuep)
220: db_expr_t *valuep;
221: {
222: db_expr_t lhs, rhs;
223: int t;
224:
225: if (!db_add_expr(&lhs))
226: return (FALSE);
227:
228: t = db_read_token();
229: while (t == tSHIFT_L || t == tSHIFT_R) {
230: if (!db_add_expr(&rhs)) {
231: db_error("Syntax error\n");
232: /*NOTREACHED*/
233: }
234: if (rhs < 0) {
235: db_error("Negative shift amount\n");
236: /*NOTREACHED*/
237: }
238: if (t == tSHIFT_L)
239: lhs <<= rhs;
240: else {
241: /* Shift right is unsigned */
242: lhs = (unsigned) lhs >> rhs;
243: }
244: t = db_read_token();
245: }
246: db_unread_token(t);
247: *valuep = lhs;
248: return (TRUE);
249: }
250:
251: int
252: db_expression(valuep)
253: db_expr_t *valuep;
254: {
255: return (db_shift_expr(valuep));
256: }
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