1 /* $NetBSD: db_access.c,v 1.17 2002/02/15 07:33:49 simonb 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@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 1.17 2002/02/15 07:33:49 simonb Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/proc.h> 37 38 #include <machine/db_machdep.h> /* type definitions */ 39 #include <machine/endian.h> 40 41 #include <ddb/db_access.h> 42 43 /* 44 * Access unaligned data items on aligned (longword) 45 * boundaries. 46 */ 47 48 const int db_extend[] = { /* table for sign-extending */ 49 0, 50 0xFFFFFF80, 51 0xFFFF8000, 52 0xFF800000 53 }; 54 55 db_expr_t 56 db_get_value(db_addr_t addr, size_t size, boolean_t is_signed) 57 { 58 char data[sizeof(db_expr_t)]; 59 db_expr_t value; 60 size_t i; 61 62 db_read_bytes(addr, size, data); 63 64 value = 0; 65 #if BYTE_ORDER == LITTLE_ENDIAN 66 for (i = size; i-- > 0;) 67 #else /* BYTE_ORDER == BIG_ENDIAN */ 68 for (i = 0; i < size; i++) 69 #endif /* BYTE_ORDER */ 70 value = (value << 8) + (data[i] & 0xFF); 71 72 if (size < 4 && is_signed && (value & db_extend[size]) != 0) 73 value |= db_extend[size]; 74 return (value); 75 } 76 77 void 78 db_put_value(db_addr_t addr, size_t size, db_expr_t value) 79 { 80 char data[sizeof(db_expr_t)]; 81 size_t i; 82 83 #if BYTE_ORDER == LITTLE_ENDIAN 84 for (i = 0; i < size; i++) 85 #else /* BYTE_ORDER == BIG_ENDIAN */ 86 for (i = size; i-- > 0;) 87 #endif /* BYTE_ORDER */ 88 { 89 data[i] = value & 0xFF; 90 value >>= 8; 91 } 92 93 db_write_bytes(addr, size, data); 94 } 95