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/* $OpenBSD: db_access.c,v 1.12 2014/09/14 14:17:24 jsg Exp $ */
/* $NetBSD: db_access.c,v 1.8 1994/10/09 08:37:35 mycroft Exp $ */
/*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* the rights to redistribute these changes.
*
* Author: David B. Golub, Carnegie Mellon University
* Date: 7/90
*/
#include <sys/param.h>
#include <machine/db_machdep.h> /* type definitions */
#include <machine/endian.h>
#include <ddb/db_access.h>
/*
* Access unaligned data items on aligned (longword)
* boundaries.
*/
db_expr_t
db_get_value(db_addr_t addr, size_t size, boolean_t is_signed)
{
char data[sizeof(db_expr_t)];
db_expr_t value, extend;
int i;
#ifdef DIAGNOSTIC
if (size > sizeof data)
size = sizeof data;
#endif
db_read_bytes(addr, size, data);
value = 0;
extend = (~(db_expr_t)0) << (size * 8 - 1);
#if BYTE_ORDER == LITTLE_ENDIAN
for (i = size - 1; i >= 0; i--)
#else /* BYTE_ORDER == BIG_ENDIAN */
for (i = 0; i < size; i++)
#endif /* BYTE_ORDER */
value = (value << 8) + (data[i] & 0xFF);
if (size < sizeof(db_expr_t) && is_signed && (value & extend))
value |= extend;
return (value);
}
void
db_put_value(db_addr_t addr, size_t size, db_expr_t value)
{
char data[sizeof(db_expr_t)];
int i;
#ifdef DIAGNOSTIC
if (size > sizeof data)
size = sizeof data;
#endif
#if BYTE_ORDER == LITTLE_ENDIAN
for (i = 0; i < size; i++)
#else /* BYTE_ORDER == BIG_ENDIAN */
for (i = size - 1; i >= 0; i--)
#endif /* BYTE_ORDER */
{
data[i] = value & 0xff;
value >>= 8;
}
db_write_bytes(addr, size, data);
}
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