1 /*- 2 * SPDX-License-Identifier: MIT-CMU 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 /* 29 * Author: David B. Golub, Carnegie Mellon University 30 * Date: 7/90 31 */ 32 33 #include <sys/cdefs.h> 34 #include <sys/param.h> 35 #include <sys/kdb.h> 36 #include <sys/endian.h> 37 38 #include <ddb/ddb.h> 39 #include <ddb/db_access.h> 40 41 /* 42 * Access unaligned data items on aligned (longword) 43 * boundaries. 44 */ 45 46 static unsigned db_extend[] = { /* table for sign-extending */ 47 0, 48 0xFFFFFF80U, 49 0xFFFF8000U, 50 0xFF800000U 51 }; 52 53 db_expr_t 54 db_get_value(db_addr_t addr, int size, bool is_signed) 55 { 56 char data[sizeof(uint64_t)]; 57 db_expr_t value; 58 int i; 59 60 if (db_read_bytes(addr, size, data) != 0) { 61 db_printf("*** error reading from address %llx ***\n", 62 (long long)addr); 63 kdb_reenter(); 64 } 65 66 value = 0; 67 #if _BYTE_ORDER == _BIG_ENDIAN 68 for (i = 0; i < size; i++) 69 #else /* _LITTLE_ENDIAN */ 70 for (i = size - 1; i >= 0; i--) 71 #endif 72 { 73 value = (value << 8) + (data[i] & 0xFF); 74 } 75 76 if (size < 4) { 77 if (is_signed && (value & db_extend[size]) != 0) 78 value |= db_extend[size]; 79 } 80 return (value); 81 } 82 83 void 84 db_put_value(db_addr_t addr, int size, db_expr_t value) 85 { 86 char data[sizeof(int)]; 87 int i; 88 89 #if _BYTE_ORDER == _BIG_ENDIAN 90 for (i = size - 1; i >= 0; i--) 91 #else /* _LITTLE_ENDIAN */ 92 for (i = 0; i < size; i++) 93 #endif 94 { 95 data[i] = value & 0xFF; 96 value >>= 8; 97 } 98 99 if (db_write_bytes(addr, size, data) != 0) { 100 db_printf("*** error writing to address %llx ***\n", 101 (long long)addr); 102 kdb_reenter(); 103 } 104 } 105