blob: 2ae40c0b6a0b33b2804361b833ac13e607884472 (
plain)
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
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
#include "../copyright"
#include "seta.h"
#include "memmap.h"
ST018_Regs ST018;
static int line; // line counter
uint8_t S9xGetST018(uint32_t Address)
{
uint8_t t = 0; // Initialise to some value for the compiler
uint16_t address = (uint16_t) Address & 0xFFFF;
line++;
// these roles may be flipped
// op output
if (address == 0x3804)
{
if (ST018.out_count)
{
t = (uint8_t) ST018.output [ST018.out_index];
ST018.out_index++;
if (ST018.out_count == ST018.out_index)
ST018.out_count = 0;
}
else
t = 0x81;
}
// status register
else if (address == 0x3800)
t = ST018.status;
printf("ST018 R: %06X %02X\n", Address, t);
return t;
}
void S9xSetST018(uint8_t Byte, uint32_t Address)
{
uint16_t address = (uint16_t) Address & 0xFFFF;
static bool reset = false;
printf("ST018 W: %06X %02X\n", Address, Byte);
line++;
if (!reset)
{
// bootup values
ST018.waiting4command = true;
ST018.part_command = 0;
reset = true;
}
Memory.SRAM[address] = Byte;
// default status for now
ST018.status = 0x00;
// op data goes through this address
if (address == 0x3804)
{
// check for new commands: 3 bytes length
if (ST018.waiting4command && ST018.part_command == 2)
{
ST018.waiting4command = false;
ST018.command <<= 8;
ST018.command |= Byte;
ST018.in_index = 0;
ST018.out_index = 0;
ST018.part_command = 0; // 3-byte commands
ST018.pass = 0; // data streams into the chip
switch (ST018.command & 0xFFFFFF)
{
case 0x0100:
ST018.in_count = 0;
break;
case 0xFF00:
ST018.in_count = 0;
break;
default:
ST018.waiting4command = true;
break;
}
}
else if (ST018.waiting4command)
{
// 3-byte commands
ST018.part_command++;
ST018.command <<= 8;
ST018.command |= Byte;
}
}
// extra parameters
else if (address == 0x3802)
{
ST018.parameters[ST018.in_index] = Byte;
ST018.in_index++;
}
if (ST018.in_count == ST018.in_index)
{
// Actually execute the command
ST018.waiting4command = true;
ST018.in_index = 0;
ST018.out_index = 0;
switch (ST018.command)
{
// hardware check?
case 0x0100:
case 0xFF00:
ST018.waiting4command = false;
ST018.pass++;
if (ST018.pass == 1)
{
ST018.in_count = 1;
ST018.out_count = 2;
// Overload's research
ST018.output[0x00] = 0x81;
ST018.output[0x01] = 0x81;
}
else
{
ST018.out_count = 3;
ST018.output[0x02] = 0x81;
// done processing requests
if (ST018.pass == 3)
ST018.waiting4command = true;
}
break;
}
}
}
|
