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db_access.c revision 1.18.42.1 
      1 /*	$NetBSD: db_access.c,v 1.18.42.1 2009/05/04 08:12:32 yamt 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 (at) 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_access.c,v 1.18.42.1 2009/05/04 08:12:32 yamt Exp $");
     34 
     35 #include <sys/param.h>
     36 #include <sys/proc.h>
     37 #include <sys/endian.h>
     38 
     39 #include <ddb/ddb.h>
     40 
     41 /*
     42  * Access unaligned data items on aligned (longword)
     43  * boundaries.
     44  */
     45 
     46 const int db_extend[] = {	/* table for sign-extending */
     47 	0,
     48 	0xFFFFFF80,
     49 	0xFFFF8000,
     50 	0xFF800000
     51 };
     52 
     53 db_expr_t
     54 db_get_value(db_addr_t addr, size_t size, bool is_signed)
     55 {
     56 	char data[sizeof(db_expr_t)];
     57 	db_expr_t value;
     58 	size_t i;
     59 
     60 	db_read_bytes(addr, size, data);
     61 
     62 	value = 0;
     63 #if BYTE_ORDER == LITTLE_ENDIAN
     64 	for (i = size; i-- > 0;)
     65 #else /* BYTE_ORDER == BIG_ENDIAN */
     66 	for (i = 0; i < size; i++)
     67 #endif /* BYTE_ORDER */
     68 		value = (value << 8) + (data[i] & 0xFF);
     69 
     70 	if (size < 4 && is_signed && (value & db_extend[size]) != 0)
     71 		value |= db_extend[size];
     72 	return (value);
     73 }
     74 
     75 void
     76 db_put_value(db_addr_t addr, size_t size, db_expr_t value)
     77 {
     78 	char data[sizeof(db_expr_t)];
     79 	size_t i;
     80 
     81 #if BYTE_ORDER == LITTLE_ENDIAN
     82 	for (i = 0; i < size; i++)
     83 #else /* BYTE_ORDER == BIG_ENDIAN */
     84 	for (i = size; i-- > 0;)
     85 #endif /* BYTE_ORDER */
     86 	{
     87 		data[i] = value & 0xFF;
     88 		value >>= 8;
     89 	}
     90 
     91 	db_write_bytes(addr, size, data);
     92 }
     93 
     94 void *
     95 db_read_ptr(const char *name)
     96 {
     97 	db_expr_t val;
     98 	void *p;
     99 
    100 	if (!db_value_of_name(name, &val)) {
    101 		db_printf("db_read_ptr: cannot find `%s'\n", name);
    102 		db_error(NULL);
    103 		/* NOTREACHED */
    104 	}
    105 	db_read_bytes((db_addr_t)val, sizeof(p), (char *)&p);
    106 	return p;
    107 }
    108 
    109 int
    110 db_read_int(const char *name)
    111 {
    112 	db_expr_t val;
    113 	int p;
    114 
    115 	if (!db_value_of_name(name, &val)) {
    116 		db_printf("db_read_int: cannot find `%s'\n", name);
    117 		db_error(NULL);
    118 		/* NOTREACHED */
    119 	}
    120 	db_read_bytes((db_addr_t)val, sizeof(p), (char *)&p);
    121 	return p;
    122 }
    123