Home | History | Annotate | Line # | Download | only in ddb
db_access.c revision 1.2.4.1 
      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 (at) 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 /*
     27  * $Id: db_access.c,v 1.2.4.1 1993/11/14 22:48:24 mycroft Exp $
     28  *
     29  * HISTORY
     30  * $Log: db_access.c,v $
     31  * Revision 1.2.4.1  1993/11/14 22:48:24  mycroft
     32  * Canonicalize all #includes.
     33  *
     34  * Revision 1.2  1993/05/20  03:39:04  cgd
     35  * add explicit rcs id
     36  *
     37  * Revision 1.1  1993/03/21  09:46:24  cgd
     38  * Initial revision
     39  *
     40  * Revision 1.1  1992/03/25  21:44:50  pace
     41  * Initial revision
     42  *
     43  * Revision 2.3  91/02/05  17:05:44  mrt
     44  * 	Changed to new Mach copyright
     45  * 	[91/01/31  16:16:22  mrt]
     46  *
     47  * Revision 2.2  90/08/27  21:48:20  dbg
     48  * 	Fix type declarations.
     49  * 	[90/08/07            dbg]
     50  * 	Created.
     51  * 	[90/07/25            dbg]
     52  *
     53  */
     54 /*
     55  *	Author: David B. Golub, Carnegie Mellon University
     56  *	Date:	7/90
     57  */
     58 #include <sys/param.h>
     59 #include <sys/proc.h>
     60 #include <machine/db_machdep.h>		/* type definitions */
     61 
     62 /*
     63  * Access unaligned data items on aligned (longword)
     64  * boundaries.
     65  */
     66 
     67 extern void	db_read_bytes();	/* machine-dependent */
     68 extern void	db_write_bytes();	/* machine-dependent */
     69 
     70 int db_extend[] = {	/* table for sign-extending */
     71 	0,
     72 	0xFFFFFF80,
     73 	0xFFFF8000,
     74 	0xFF800000
     75 };
     76 
     77 db_expr_t
     78 db_get_value(addr, size, is_signed)
     79 	db_addr_t	addr;
     80 	register int	size;
     81 	boolean_t	is_signed;
     82 {
     83 	char		data[sizeof(int)];
     84 	register db_expr_t value;
     85 	register int	i;
     86 
     87 	db_read_bytes(addr, size, data);
     88 
     89 	value = 0;
     90 #if	BYTE_MSF
     91 	for (i = 0; i < size; i++)
     92 #else	/* BYTE_LSF */
     93 	for (i = size - 1; i >= 0; i--)
     94 #endif
     95 	{
     96 	    value = (value << 8) + (data[i] & 0xFF);
     97 	}
     98 
     99 	if (size < 4) {
    100 	    if (is_signed && (value & db_extend[size]) != 0)
    101 		value |= db_extend[size];
    102 	}
    103 	return (value);
    104 }
    105 
    106 void
    107 db_put_value(addr, size, value)
    108 	db_addr_t	addr;
    109 	register int	size;
    110 	register db_expr_t value;
    111 {
    112 	char		data[sizeof(int)];
    113 	register int	i;
    114 
    115 #if	BYTE_MSF
    116 	for (i = size - 1; i >= 0; i--)
    117 #else	/* BYTE_LSF */
    118 	for (i = 0; i < size; i++)
    119 #endif
    120 	{
    121 	    data[i] = value & 0xFF;
    122 	    value >>= 8;
    123 	}
    124 
    125 	db_write_bytes(addr, size, data);
    126 }
    127 
    128