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Annotation of sys/ddb/db_access.c, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: db_access.c,v 1.10 2007/03/15 17:10:22 miod Exp $     */
                      2: /*     $NetBSD: db_access.c,v 1.8 1994/10/09 08:37:35 mycroft Exp $    */
                      3:
                      4: /*
                      5:  * Mach Operating System
                      6:  * Copyright (c) 1991,1990 Carnegie Mellon University
                      7:  * All Rights Reserved.
                      8:  *
                      9:  * Permission to use, copy, modify and distribute this software and its
                     10:  * documentation is hereby granted, provided that both the copyright
                     11:  * notice and this permission notice appear in all copies of the
                     12:  * software, derivative works or modified versions, and any portions
                     13:  * thereof, and that both notices appear in supporting documentation.
                     14:  *
                     15:  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
                     16:  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
                     17:  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
                     18:  *
                     19:  * Carnegie Mellon requests users of this software to return to
                     20:  *
                     21:  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
                     22:  *  School of Computer Science
                     23:  *  Carnegie Mellon University
                     24:  *  Pittsburgh PA 15213-3890
                     25:  *
                     26:  * any improvements or extensions that they make and grant Carnegie the
                     27:  * the rights to redistribute these changes.
                     28:  *
                     29:  *     Author: David B. Golub, Carnegie Mellon University
                     30:  *     Date:   7/90
                     31:  */
                     32:
                     33: #include <sys/param.h>
                     34: #include <sys/proc.h>
                     35:
                     36: #include <uvm/uvm_extern.h>
                     37:
                     38: #include <machine/db_machdep.h>                /* type definitions */
                     39: #include <machine/endian.h>
                     40:
                     41: #include <ddb/db_access.h>
                     42:
                     43: /*
                     44:  * Access unaligned data items on aligned (longword)
                     45:  * boundaries.
                     46:  */
                     47: db_expr_t
                     48: db_get_value(db_addr_t addr, size_t size, boolean_t is_signed)
                     49: {
                     50:        char data[sizeof(db_expr_t)];
                     51:        db_expr_t value, extend;
                     52:        int i;
                     53:
                     54: #ifdef DIAGNOSTIC
                     55:        if (size > sizeof data)
                     56:                size = sizeof data;
                     57: #endif
                     58:
                     59:        db_read_bytes(addr, size, data);
                     60:
                     61:        value = 0;
                     62:        extend = (~(db_expr_t)0) << (size * 8 - 1);
                     63: #if BYTE_ORDER == LITTLE_ENDIAN
                     64:        for (i = size - 1; i >= 0; i--)
                     65: #else /* BYTE_ORDER == BIG_ENDIAN */
                     66:        for (i = 0; i < size; i++)
                     67: #endif /* BYTE_ORDER */
                     68:                value = (value << 8) + (data[i] & 0xFF);
                     69:
                     70:        if (size < sizeof(db_expr_t) && is_signed && (value & extend))
                     71:                value |= extend;
                     72:        return (value);
                     73: }
                     74:
                     75: void
                     76: db_put_value(db_addr_t addr, size_t size, db_expr_t value)
                     77: {
                     78:        char data[sizeof(db_expr_t)];
                     79:        int i;
                     80:
                     81: #ifdef DIAGNOSTIC
                     82:        if (size > sizeof data)
                     83:                size = sizeof data;
                     84: #endif
                     85:
                     86: #if BYTE_ORDER == LITTLE_ENDIAN
                     87:        for (i = 0; i < size; i++)
                     88: #else /* BYTE_ORDER == BIG_ENDIAN */
                     89:        for (i = size - 1; i >= 0; i--)
                     90: #endif /* BYTE_ORDER */
                     91:        {
                     92:                data[i] = value & 0xff;
                     93:                value >>= 8;
                     94:        }
                     95:
                     96:        db_write_bytes(addr, size, data);
                     97: }