diff options
Diffstat (limited to 'sys/ddb/db_expr.c')
| -rw-r--r-- | sys/ddb/db_expr.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/sys/ddb/db_expr.c b/sys/ddb/db_expr.c new file mode 100644 index 00000000000..1182a1f9993 --- /dev/null +++ b/sys/ddb/db_expr.c @@ -0,0 +1,226 @@ +/* $NetBSD: db_expr.c,v 1.4 1994/06/29 06:31:06 cgd Exp $ */ + +/* + * Mach Operating System + * Copyright (c) 1991,1990 Carnegie Mellon University + * All Rights Reserved. + * + * Permission to use, copy, modify and distribute this software and its + * documentation is hereby granted, provided that both the copyright + * notice and this permission notice appear in all copies of the + * software, derivative works or modified versions, and any portions + * thereof, and that both notices appear in supporting documentation. + * + * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS + * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR + * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. + * + * Carnegie Mellon requests users of this software to return to + * + * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU + * School of Computer Science + * Carnegie Mellon University + * Pittsburgh PA 15213-3890 + * + * any improvements or extensions that they make and grant Carnegie the + * rights to redistribute these changes. + * + * Author: David B. Golub, Carnegie Mellon University + * Date: 7/90 + */ + +#include <sys/param.h> +#include <sys/proc.h> + +#include <machine/db_machdep.h> + +#include <ddb/db_lex.h> +#include <ddb/db_access.h> +#include <ddb/db_command.h> + +boolean_t +db_term(valuep) + db_expr_t *valuep; +{ + int t; + + t = db_read_token(); + if (t == tIDENT) { + if (!db_value_of_name(db_tok_string, valuep)) { + db_error("Symbol not found\n"); + /*NOTREACHED*/ + } + return (TRUE); + } + if (t == tNUMBER) { + *valuep = (db_expr_t)db_tok_number; + return (TRUE); + } + if (t == tDOT) { + *valuep = (db_expr_t)db_dot; + return (TRUE); + } + if (t == tDOTDOT) { + *valuep = (db_expr_t)db_prev; + return (TRUE); + } + if (t == tPLUS) { + *valuep = (db_expr_t) db_next; + return (TRUE); + } + if (t == tDITTO) { + *valuep = (db_expr_t)db_last_addr; + return (TRUE); + } + if (t == tDOLLAR) { + if (!db_get_variable(valuep)) + return (FALSE); + return (TRUE); + } + if (t == tLPAREN) { + if (!db_expression(valuep)) { + db_error("Syntax error\n"); + /*NOTREACHED*/ + } + t = db_read_token(); + if (t != tRPAREN) { + db_error("Syntax error\n"); + /*NOTREACHED*/ + } + return (TRUE); + } + db_unread_token(t); + return (FALSE); +} + +boolean_t +db_unary(valuep) + db_expr_t *valuep; +{ + int t; + + t = db_read_token(); + if (t == tMINUS) { + if (!db_unary(valuep)) { + db_error("Syntax error\n"); + /*NOTREACHED*/ + } + *valuep = -*valuep; + return (TRUE); + } + if (t == tSTAR) { + /* indirection */ + if (!db_unary(valuep)) { + db_error("Syntax error\n"); + /*NOTREACHED*/ + } + *valuep = db_get_value((db_addr_t)*valuep, sizeof(int), FALSE); + return (TRUE); + } + db_unread_token(t); + return (db_term(valuep)); +} + +boolean_t +db_mult_expr(valuep) + db_expr_t *valuep; +{ + db_expr_t lhs, rhs; + int t; + + if (!db_unary(&lhs)) + return (FALSE); + + t = db_read_token(); + while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) { + if (!db_term(&rhs)) { + db_error("Syntax error\n"); + /*NOTREACHED*/ + } + if (t == tSTAR) + lhs *= rhs; + else { + if (rhs == 0) { + db_error("Divide by 0\n"); + /*NOTREACHED*/ + } + if (t == tSLASH) + lhs /= rhs; + else if (t == tPCT) + lhs %= rhs; + else + lhs = ((lhs+rhs-1)/rhs)*rhs; + } + t = db_read_token(); + } + db_unread_token(t); + *valuep = lhs; + return (TRUE); +} + +boolean_t +db_add_expr(valuep) + db_expr_t *valuep; +{ + db_expr_t lhs, rhs; + int t; + + if (!db_mult_expr(&lhs)) + return (FALSE); + + t = db_read_token(); + while (t == tPLUS || t == tMINUS) { + if (!db_mult_expr(&rhs)) { + db_error("Syntax error\n"); + /*NOTREACHED*/ + } + if (t == tPLUS) + lhs += rhs; + else + lhs -= rhs; + t = db_read_token(); + } + db_unread_token(t); + *valuep = lhs; + return (TRUE); +} + +boolean_t +db_shift_expr(valuep) + db_expr_t *valuep; +{ + db_expr_t lhs, rhs; + int t; + + if (!db_add_expr(&lhs)) + return (FALSE); + + t = db_read_token(); + while (t == tSHIFT_L || t == tSHIFT_R) { + if (!db_add_expr(&rhs)) { + db_error("Syntax error\n"); + /*NOTREACHED*/ + } + if (rhs < 0) { + db_error("Negative shift amount\n"); + /*NOTREACHED*/ + } + if (t == tSHIFT_L) + lhs <<= rhs; + else { + /* Shift right is unsigned */ + lhs = (unsigned) lhs >> rhs; + } + t = db_read_token(); + } + db_unread_token(t); + *valuep = lhs; + return (TRUE); +} + +int +db_expression(valuep) + db_expr_t *valuep; +{ + return (db_shift_expr(valuep)); +} |