src/devices/dev_zero.c

/*
 *  Copyright (C) 2004-2007  Anders Gavare.  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright  
 *     notice, this list of conditions and the following disclaimer in the 
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE   
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 *  SUCH DAMAGE.
 *   
 *
 *  $Id: dev_zero.c,v 1.8 2007/06/15 20:11:27 debug Exp $
 *  
 *  COMMENT: A simple device which returns zero for reads, discards all writes
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "device.h"
#include "machine.h"
#include "memory.h"
#include "misc.h"


DEVICE_ACCESS(zero)
{
        if (writeflag == MEM_READ) {
                size_t i;
                for (i=0; i<len; i++)
                        data[i] = 0;
        }

        return 1;
}


DEVINIT(zero)
{
        memory_device_register(devinit->machine->memory,
            devinit->name, devinit->addr, devinit->len,
            dev_zero_access, NULL, DM_DEFAULT, NULL);

        return 1;
}

1	/*
2	* Copyright (C) 2004-2007 Anders Gavare. All rights reserved.
3	*
4	* Redistribution and use in source and binary forms, with or without
5	* modification, are permitted provided that the following conditions are met:
6	*
7	* 1. Redistributions of source code must retain the above copyright
8	* notice, this list of conditions and the following disclaimer.
9	* 2. Redistributions in binary form must reproduce the above copyright
10	* notice, this list of conditions and the following disclaimer in the
11	* documentation and/or other materials provided with the distribution.
12	* 3. The name of the author may not be used to endorse or promote products
13	* derived from this software without specific prior written permission.
14	*
15	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25	* SUCH DAMAGE.
26	*
27	*
28	* $Id: dev_zero.c,v 1.8 2007/06/15 20:11:27 debug Exp $
29	*
30	* COMMENT: A simple device which returns zero for reads, discards all writes
31	*/
32
33	#include <stdio.h>
34	#include <stdlib.h>
35	#include <string.h>
36
37	#include "device.h"
38	#include "machine.h"
39	#include "memory.h"
40	#include "misc.h"
41
42
43	DEVICE_ACCESS(zero)
44	{
45	if (writeflag == MEM_READ) {
46	size_t i;
47	for (i=0; i<len; i++)
48	data[i] = 0;
49	}
50
51	return 1;
52	}
53
54
55	DEVINIT(zero)
56	{
57	memory_device_register(devinit->machine->memory,
58	devinit->name, devinit->addr, devinit->len,
59	dev_zero_access, NULL, DM_DEFAULT, NULL);
60
61	return 1;
62	}
63