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Annotation of Net2/ddb/db_access.c, revision 1.1.1.1

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

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