1 /* $OpenBSD: db_access.c,v 1.16 2019/11/07 13:16:25 mpi 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/endian.h> 35 36 #include <machine/db_machdep.h> /* type definitions */ 37 38 #include <ddb/db_access.h> 39 40 /* 41 * Access unaligned data items on aligned (longword) 42 * boundaries. 43 */ 44 db_expr_t 45 db_get_value(vaddr_t addr, size_t size, int is_signed) 46 { 47 char data[sizeof(db_expr_t)]; 48 db_expr_t value, extend; 49 int i; 50 51 #ifdef DIAGNOSTIC 52 if (size > sizeof data) 53 size = sizeof data; 54 #endif 55 56 db_read_bytes(addr, size, data); 57 58 value = 0; 59 extend = (~(db_expr_t)0) << (size * 8 - 1); 60 #if BYTE_ORDER == LITTLE_ENDIAN 61 for (i = size - 1; i >= 0; i--) 62 #else /* BYTE_ORDER == BIG_ENDIAN */ 63 for (i = 0; i < size; i++) 64 #endif /* BYTE_ORDER */ 65 value = (value << 8) + (data[i] & 0xFF); 66 67 if (size < sizeof(db_expr_t) && is_signed && (value & extend)) 68 value |= extend; 69 return (value); 70 } 71 72 void 73 db_put_value(vaddr_t addr, size_t size, db_expr_t value) 74 { 75 char data[sizeof(db_expr_t)]; 76 int i; 77 78 #ifdef DIAGNOSTIC 79 if (size > sizeof data) 80 size = sizeof data; 81 #endif 82 83 #if BYTE_ORDER == LITTLE_ENDIAN 84 for (i = 0; i < size; i++) 85 #else /* BYTE_ORDER == BIG_ENDIAN */ 86 for (i = size - 1; i >= 0; i--) 87 #endif /* BYTE_ORDER */ 88 { 89 data[i] = value & 0xff; 90 value >>= 8; 91 } 92 93 db_write_bytes(addr, size, data); 94 } 95