Annotation of Net2/ddb/db_access.c, revision 1.1.1.3

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

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