1 /*
2 * Copyright (C) 2004-2009 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 * COMMENT: A simple device which returns zero for reads, discards all writes
29 */
30
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34
35 #include "device.h"
36 #include "machine.h"
37 #include "memory.h"
38 #include "misc.h"
39
40
DEVICE_ACCESS(zero)41 DEVICE_ACCESS(zero)
42 {
43 if (writeflag == MEM_READ) {
44 size_t i;
45 for (i=0; i<len; i++)
46 data[i] = 0;
47 }
48
49 return 1;
50 }
51
52
DEVINIT(zero)53 DEVINIT(zero)
54 {
55 memory_device_register(devinit->machine->memory,
56 devinit->name, devinit->addr, devinit->len,
57 dev_zero_access, NULL, DM_DEFAULT, NULL);
58
59 return 1;
60 }
61
62