1 #ifndef lint 2 static char sccsid[] = "@(#)random.c 5.1 (Berkeley) 11/25/87"; 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 } 93