1 /* $NetBSD: db_access.c,v 1.5 1994/06/29 06:30:55 cgd 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 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/param.h> 33 #include <sys/proc.h> 34 35 #include <machine/db_machdep.h> /* type definitions */ 36 37 /* 38 * Access unaligned data items on aligned (longword) 39 * boundaries. 40 */ 41 42 extern void db_read_bytes(); /* machine-dependent */ 43 extern void db_write_bytes(); /* machine-dependent */ 44 45 int db_extend[] = { /* table for sign-extending */ 46 0, 47 0xFFFFFF80, 48 0xFFFF8000, 49 0xFF800000 50 }; 51 52 db_expr_t 53 db_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 #ifdef 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 81 void 82 db_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 #ifdef 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