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 */ 28 29 /* 30 * Author: David B. Golub, Carnegie Mellon University 31 * Date: 7/90 32 */ 33 #include <sys/param.h> 34 #include <machine/limits.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 #if LONG_BIT == 32 45 46 static unsigned db_extend[] = { /* table for sign-extending */ 47 0, 48 0xFFFFFF80U, 49 0xFFFF8000U, 50 0xFF800000U 51 }; 52 53 #else 54 55 static unsigned long db_extend[] = { /* table for sign-extending */ 56 0, 57 0xFFFFFFFFFFFFFF80LU, 58 0xFFFFFFFFFFFF8000LU, 59 0xFFFFFFFFFF800000LU, 60 0xFFFFFFFF80000000LU, 61 0xFFFFFF8000000000LU, 62 0xFFFF800000000000LU, 63 0xFF80000000000000LU 64 }; 65 66 #endif 67 68 #ifndef BYTE_MSF 69 #define BYTE_MSF 0 70 #endif 71 72 db_expr_t 73 db_get_value(db_addr_t addr, int size, boolean_t is_signed) 74 { 75 char data[sizeof(long)]; 76 int i; 77 db_expr_t value; 78 79 if (size > sizeof(long)) 80 size = sizeof(long); 81 82 db_read_bytes(addr, size, data); 83 84 value = 0; 85 #if BYTE_MSF 86 for (i = 0; i < size; i++) 87 #else /* BYTE_LSF */ 88 for (i = size - 1; i >= 0; i--) 89 #endif 90 { 91 value = (value << 8) + (data[i] & 0xFF); 92 } 93 94 if (size < sizeof(long)) { 95 if (is_signed && (value & db_extend[size]) != 0) 96 value |= db_extend[size]; 97 } 98 return (value); 99 } 100 101 void 102 db_put_value(db_addr_t addr, int size, db_expr_t value) 103 { 104 char data[sizeof(long)]; 105 int i; 106 107 if (size > sizeof(long)) 108 size = sizeof(long); 109 110 #if BYTE_MSF 111 for (i = size - 1; i >= 0; i--) 112 #else /* BYTE_LSF */ 113 for (i = 0; i < size; i++) 114 #endif 115 { 116 data[i] = value & 0xFF; 117 value >>= 8; 118 } 119 120 db_write_bytes(addr, size, data); 121 } 122 123