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1 | #ifndef lint |
2 | static char sccsid[] = "@(#)random.c 5.1 (Berkeley) %G%"; | |
3 | #endif /* not lint */ | |
4 | ||
5 | static long rntb[32] = { | |
6 | 3, 0x9a319039, 0x32d9c024, 0x9b663182, 0x5da1f342, | |
7 | 0xde3b81e0, 0xdf0a6fb5, 0xf103bc02, 0x48f340fb, 0x7449e56b, | |
8 | 0xbeb1dbb0, 0xab5c5918, 0x946554fd, 0x8c2e680f, 0xeb3d799f, | |
9 | 0xb11ee0b7, 0x2d436b86, 0xda672e2a, 0x1588ca88, 0xe369735d, | |
10 | 0x904f35f7, 0xd7158fd6, 0x6fa6f051, 0x616e6b96, 0xac94efdc, | |
11 | 0x36413f93, 0xc622c298, 0xf5a42ab8, 0x8a88d77b, 0xf5ad9d0e, | |
12 | 0x8999220b, 0x27fb47b9 | |
13 | }; | |
14 | ||
15 | static long *fptr = &rntb[4]; | |
16 | static long *rptr = &rntb[1]; | |
17 | static long *state = &rntb[1]; | |
18 | static int rand_type = 3; | |
19 | static int rand_deg = 31; | |
20 | static int rand_sep = 3; | |
21 | static long *end_ptr = &rntb[32]; | |
22 | ||
23 | srrandom(x) | |
24 | int x; | |
25 | { | |
26 | register int i; | |
27 | long rrandom(); | |
28 | ||
29 | state[0] = (long) x; | |
30 | if (rand_type != 0) { | |
31 | for (i = 1; i < rand_deg; i++) { | |
32 | state[i] = 1103515245 * state[i - 1] + 12345; | |
33 | } | |
34 | fptr = &state[rand_sep]; | |
35 | rptr = &state[0]; | |
36 | for (i = 0; i < 10 * rand_deg; i++) { | |
37 | (void) rrandom(); | |
38 | } | |
39 | } | |
40 | } | |
41 | ||
42 | long | |
43 | rrandom() | |
44 | { | |
45 | long i; | |
46 | ||
47 | if (rand_type == 0) { | |
48 | i = state[0] = (state[0]*1103515245 + 12345) & 0x7fffffff; | |
49 | } else { | |
50 | *fptr += *rptr; | |
51 | i = (*fptr >> 1) & 0x7fffffff; | |
52 | if (++fptr >= end_ptr) { | |
53 | fptr = state; | |
54 | ++rptr; | |
55 | } else { | |
56 | if (++rptr >= end_ptr) { | |
57 | rptr = state; | |
58 | } | |
59 | } | |
60 | } | |
61 | return(i); | |
62 | } | |
63 | ||
64 | get_rand(x, y) | |
65 | register int x, y; | |
66 | { | |
67 | register int r, t; | |
68 | long lr; | |
69 | ||
70 | if (x > y) { | |
71 | t = y; | |
72 | y = x; | |
73 | x = t; | |
74 | } | |
75 | lr = rrandom(); | |
76 | lr &= (long) 0x00003fff; | |
77 | r = (int) lr; | |
78 | r = (r % ((y - x) + 1)) + x; | |
79 | return(r); | |
80 | } | |
81 | ||
82 | rand_percent(percentage) | |
83 | register int percentage; | |
84 | { | |
85 | return(get_rand(1, 100) <= percentage); | |
86 | } | |
87 | ||
88 | coin_toss() | |
89 | { | |
90 | ||
91 | return(((rrandom() & 01) ? 1 : 0)); | |
92 | } |