NetBSD/sys/ddb/db_access.c

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/* $NetBSD: db_access.c,v 1.17 2002/02/15 07:33:49 simonb Exp $ */
/*
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* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
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* 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 "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
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* Carnegie Mellon requests users of this software to return to
*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
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* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
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*
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* Author: David B. Golub, Carnegie Mellon University
* Date: 7/90
*/
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#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: db_access.c,v 1.17 2002/02/15 07:33:49 simonb Exp $");
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#include <sys/param.h>
#include <sys/proc.h>
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#include <machine/db_machdep.h> /* type definitions */
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#include <machine/endian.h>
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#include <ddb/db_access.h>
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/*
* Access unaligned data items on aligned (longword)
* boundaries.
*/
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const int db_extend[] = { /* table for sign-extending */
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0,
0xFFFFFF80,
0xFFFF8000,
0xFF800000
};
db_expr_t
db_get_value(db_addr_t addr, size_t size, boolean_t is_signed)
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{
char data[sizeof(db_expr_t)];
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db_expr_t value;
size_t i;
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db_read_bytes(addr, size, data);
value = 0;
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#if BYTE_ORDER == LITTLE_ENDIAN
for (i = size; i-- > 0;)
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#else /* BYTE_ORDER == BIG_ENDIAN */
for (i = 0; i < size; i++)
#endif /* BYTE_ORDER */
value = (value << 8) + (data[i] & 0xFF);
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if (size < 4 && is_signed && (value & db_extend[size]) != 0)
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value |= db_extend[size];
return (value);
}
void
db_put_value(db_addr_t addr, size_t size, db_expr_t value)
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{
char data[sizeof(db_expr_t)];
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size_t i;
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#if BYTE_ORDER == LITTLE_ENDIAN
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for (i = 0; i < size; i++)
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#else /* BYTE_ORDER == BIG_ENDIAN */
for (i = size; i-- > 0;)
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#endif /* BYTE_ORDER */
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{
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data[i] = value & 0xFF;
value >>= 8;
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}
db_write_bytes(addr, size, data);
}