1 /* 2 * Mach Operating System 3 * Copyright (c) 1991,1990 Carnegie Mellon University 4 * All Rights Reserved. 5 * 6 * Permission to use, copy, modify and distribute this software and its 7 * documentation is hereby granted, provided that both the copyright 8 * notice and this permission notice appear in all copies of the 9 * software, derivative works or modified versions, and any portions 10 * thereof, and that both notices appear in supporting documentation. 11 * 12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 13 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 15 * 16 * Carnegie Mellon requests users of this software to return to 17 * 18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 19 * School of Computer Science 20 * Carnegie Mellon University 21 * Pittsburgh PA 15213-3890 22 * 23 * any improvements or extensions that they make and grant Carnegie the 24 * rights to redistribute these changes. 25 * 26 * $FreeBSD: src/sys/ddb/db_access.c,v 1.15 1999/08/28 00:41:04 peter Exp $ 27 * $DragonFly: src/sys/ddb/db_access.c,v 1.3 2003/07/26 14:18:51 rob Exp $ 28 */ 29 30 /* 31 * Author: David B. Golub, Carnegie Mellon University 32 * Date: 7/90 33 */ 34 #include <sys/param.h> 35 36 #include <ddb/ddb.h> 37 #include <ddb/db_access.h> 38 39 /* 40 * Access unaligned data items on aligned (longword) 41 * boundaries. 42 */ 43 44 static unsigned db_extend[] = { /* table for sign-extending */ 45 0, 46 0xFFFFFF80U, 47 0xFFFF8000U, 48 0xFF800000U 49 }; 50 51 db_expr_t 52 db_get_value(addr, size, is_signed) 53 db_addr_t addr; 54 int size; 55 boolean_t is_signed; 56 { 57 char data[sizeof(int)]; 58 db_expr_t value; 59 int i; 60 61 db_read_bytes(addr, size, data); 62 63 value = 0; 64 #if BYTE_MSF 65 for (i = 0; i < size; i++) 66 #else /* BYTE_LSF */ 67 for (i = size - 1; i >= 0; i--) 68 #endif 69 { 70 value = (value << 8) + (data[i] & 0xFF); 71 } 72 73 if (size < 4) { 74 if (is_signed && (value & db_extend[size]) != 0) 75 value |= db_extend[size]; 76 } 77 return (value); 78 } 79 80 void 81 db_put_value(addr, size, value) 82 db_addr_t addr; 83 int size; 84 db_expr_t value; 85 { 86 char data[sizeof(int)]; 87 int i; 88 89 #if BYTE_MSF 90 for (i = size - 1; i >= 0; i--) 91 #else /* BYTE_LSF */ 92 for (i = 0; i < size; i++) 93 #endif 94 { 95 data[i] = value & 0xFF; 96 value >>= 8; 97 } 98 99 db_write_bytes(addr, size, data); 100 } 101 102