db_access.c revision 12662
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 * $Id: db_access.c,v 1.9 1995/11/29 10:25:03 phk Exp $ 27 */ 28 29/* 30 * Author: David B. Golub, Carnegie Mellon University 31 * Date: 7/90 32 */ 33#include <sys/param.h> 34#include <sys/systm.h> 35#include <sys/proc.h> 36#include <vm/vm_param.h> 37#include <ddb/ddb.h> 38#include <ddb/db_access.h> 39 40/* 41 * Access unaligned data items on aligned (longword) 42 * boundaries. 43 */ 44 45static unsigned db_extend[] = { /* table for sign-extending */ 46 0, 47 0xFFFFFF80U, 48 0xFFFF8000U, 49 0xFF800000U 50}; 51 52db_expr_t 53db_get_value(addr, size, is_signed) 54 db_addr_t addr; 55 register int size; 56 boolean_t is_signed; 57{ 58 char data[sizeof(int)]; 59 register db_expr_t value; 60 register int i; 61 62 db_read_bytes(addr, size, data); 63 64 value = 0; 65#if BYTE_MSF 66 for (i = 0; i < size; i++) 67#else /* BYTE_LSF */ 68 for (i = size - 1; i >= 0; i--) 69#endif 70 { 71 value = (value << 8) + (data[i] & 0xFF); 72 } 73 74 if (size < 4) { 75 if (is_signed && (value & db_extend[size]) != 0) 76 value |= db_extend[size]; 77 } 78 return (value); 79} 80 81void 82db_put_value(addr, size, value) 83 db_addr_t addr; 84 register int size; 85 register db_expr_t value; 86{ 87 char data[sizeof(int)]; 88 register int i; 89 90#if BYTE_MSF 91 for (i = size - 1; i >= 0; i--) 92#else /* BYTE_LSF */ 93 for (i = 0; i < size; i++) 94#endif 95 { 96 data[i] = value & 0xFF; 97 value >>= 8; 98 } 99 100 db_write_bytes(addr, size, data); 101} 102 103