1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
/*
Fake86: A portable, open-source 8086 PC emulator.
Copyright (C)2010-2013 Mike Chambers
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/* ssource.c: functions to emulate the Disney Sound Source's 16-byte FIFO buffer. */
#include "config.h"
#include <stdint.h>
extern void set_port_write_redirector (uint16_t startport, uint16_t endport, void *callback);
extern void set_port_read_redirector (uint16_t startport, uint16_t endport, void *callback);
extern uint8_t portram[0x10000];
uint8_t ssourcebuf[16], ssourceptr = 0, ssourceactive = 0;
int16_t ssourcecursample = 0;
int16_t getssourcebyte() {
return (ssourcecursample);
}
void tickssource() {
uint8_t rotatefifo;
if ( (ssourceptr==0) || (!ssourceactive) ) {
ssourcecursample = 0;
return;
}
ssourcecursample = ssourcebuf[0];
for (rotatefifo=1; rotatefifo<16; rotatefifo++)
ssourcebuf[rotatefifo-1] = ssourcebuf[rotatefifo];
ssourceptr--;
portram[0x379] = 0;
}
void putssourcebyte (uint8_t value) {
if (ssourceptr==16) return;
ssourcebuf[ssourceptr++] = value;
if (ssourceptr==16) portram[0x379] = 0x40;
}
uint8_t ssourcefull() {
if (ssourceptr==16) return (0x40);
else return (0x00);
}
void outsoundsource (uint16_t portnum, uint8_t value) {
static uint8_t last37a = 0;
switch (portnum) {
case 0x378:
putssourcebyte (value);
break;
case 0x37A:
if ( (value & 4) && ! (last37a & 4) ) putssourcebyte (portram[0x378]);
last37a = value;
break;
}
}
uint8_t insoundsource (uint16_t portnum) {
return (ssourcefull() );
}
void initsoundsource() {
set_port_write_redirector (0x378, 0x378, &outsoundsource);
set_port_write_redirector (0x37A, 0x37A, &outsoundsource);
set_port_read_redirector (0x379, 0x379, &insoundsource);
ssourceactive = 1;
}
|
