1 /* $OpenBSD: db_access.c,v 1.11 2014/07/08 13:02:57 deraadt Exp $ */ 2 /* $NetBSD: db_access.c,v 1.8 1994/10/09 08:37:35 mycroft Exp $ */ 3 4 /* 5 * Mach Operating System 6 * Copyright (c) 1991,1990 Carnegie Mellon University 7 * All Rights Reserved. 8 * 9 * Permission to use, copy, modify and distribute this software and its 10 * documentation is hereby granted, provided that both the copyright 11 * notice and this permission notice appear in all copies of the 12 * software, derivative works or modified versions, and any portions 13 * thereof, and that both notices appear in supporting documentation. 14 * 15 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 16 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 17 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 18 * 19 * Carnegie Mellon requests users of this software to return to 20 * 21 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 22 * School of Computer Science 23 * Carnegie Mellon University 24 * Pittsburgh PA 15213-3890 25 * 26 * any improvements or extensions that they make and grant Carnegie the 27 * the rights to redistribute these changes. 28 * 29 * Author: David B. Golub, Carnegie Mellon University 30 * Date: 7/90 31 */ 32 33 #include <sys/param.h> 34 #include <sys/proc.h> 35 36 #include <machine/db_machdep.h> /* type definitions */ 37 #include <machine/endian.h> 38 39 #include <ddb/db_access.h> 40 41 /* 42 * Access unaligned data items on aligned (longword) 43 * boundaries. 44 */ 45 db_expr_t 46 db_get_value(db_addr_t addr, size_t size, boolean_t is_signed) 47 { 48 char data[sizeof(db_expr_t)]; 49 db_expr_t value, extend; 50 int i; 51 52 #ifdef DIAGNOSTIC 53 if (size > sizeof data) 54 size = sizeof data; 55 #endif 56 57 db_read_bytes(addr, size, data); 58 59 value = 0; 60 extend = (~(db_expr_t)0) << (size * 8 - 1); 61 #if BYTE_ORDER == LITTLE_ENDIAN 62 for (i = size - 1; i >= 0; i--) 63 #else /* BYTE_ORDER == BIG_ENDIAN */ 64 for (i = 0; i < size; i++) 65 #endif /* BYTE_ORDER */ 66 value = (value << 8) + (data[i] & 0xFF); 67 68 if (size < sizeof(db_expr_t) && is_signed && (value & extend)) 69 value |= extend; 70 return (value); 71 } 72 73 void 74 db_put_value(db_addr_t addr, size_t size, db_expr_t value) 75 { 76 char data[sizeof(db_expr_t)]; 77 int i; 78 79 #ifdef DIAGNOSTIC 80 if (size > sizeof data) 81 size = sizeof data; 82 #endif 83 84 #if BYTE_ORDER == LITTLE_ENDIAN 85 for (i = 0; i < size; i++) 86 #else /* BYTE_ORDER == BIG_ENDIAN */ 87 for (i = size - 1; i >= 0; i--) 88 #endif /* BYTE_ORDER */ 89 { 90 data[i] = value & 0xff; 91 value >>= 8; 92 } 93 94 db_write_bytes(addr, size, data); 95 } 96