1 /*
2  * C copy protection routines
3  */
4 
5 #include	"swint.h"
6 
7 extern int goodchk;
8 int no_step;
9 
10 #define UNDEFINED	0
11 #define DONTCARE	0
12 
13 #define	CRC		0x10
14 
15 static struct sw_regs rom_read = {
16 	0x206,
17 	0,
18 	0x2701,
19 	UNDEFINED,
20 	DONTCARE,
21 	DONTCARE,
22 	DONTCARE,
23 	0xF800
24 } ;
25 
26 static struct sw_regs sig1_read = {
27 	0x201,
28 	UNDEFINED,
29 	0x2707,
30 	UNDEFINED,
31 	DONTCARE,
32 	DONTCARE,
33 	DONTCARE,
34 	UNDEFINED
35 } ;
36 
37 static struct sw_regs sig2_read = {
38 	0x201,
39 	UNDEFINED,
40 	0x27F1,
41 	UNDEFINED,
42 	DONTCARE,
43 	DONTCARE,
44 	DONTCARE,
45 	UNDEFINED
46 } ;
47 
48 protect(drive)
49 {
50 	int i, flags;
51 	struct sw_regs rgs;
52 	char buf2[512];
53 	char buf1[32];
54 
55 	no_step++;
56 	rom_read.dx = sig1_read.dx = sig2_read.dx = drive;
57 	sig1_read.es = sig2_read.es = getds();
58 	sig1_read.bx = (int)(&buf1[0]);
59 	sig2_read.bx = (int)(&buf2[0]);
60 
61 	for (i=0,flags=CF;i<7 && (flags&CF);i++)
62 	{
63 		rgs = rom_read;
64 		no_step = 0;
65 		flags = sysint(SW_DSK,&rgs,&rgs);
66 		no_step++;
67 	}
68 	if (CF&flags)
69 	{
70 		no_step = 0;
71 		return;
72 	}
73 	for (i=0,flags=CF;i<3 && (flags&CF);i++)
74 	{
75 		rgs = sig1_read;
76 		no_step = 0;
77 		flags = sysint(SW_DSK,&rgs,&rgs);
78 		no_step++;
79 	}
80 	if (CF&flags)
81 	{
82 		no_step = 0;
83 		return;
84 	}
85 	for (i=0;i<4;i++)
86 	{
87 		rgs = sig2_read;
88 		no_step = 0;
89 		flags = sysint(SW_DSK,&rgs,&rgs);
90 		no_step++;
91 		if ((flags&CF) && HI(rgs.ax) == CRC)
92 		{
93 			if (memcmp(&buf1[0],&buf2[0x8c],32) == 0)
94 				goodchk = 0xD0D;
95 			no_step = 0;
96 			return ;
97 		}
98 	}
99 	no_step = 0;
100 }
101 ÿ