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2aa62f2b | 1 | /*-\r |
2 | * Portions Copyright (c) 2010, Intel Corporation. All rights reserved.<BR>\r | |
3 | * Copyright (c) 1990, 1993\r | |
4 | * The Regents of the University of California. All rights reserved.\r | |
5 | *\r | |
6 | * Redistribution and use in source and binary forms, with or without\r | |
7 | * modification, are permitted provided that the following conditions\r | |
8 | * are met:\r | |
9 | * 1. Redistributions of source code must retain the above copyright\r | |
10 | * notice, this list of conditions and the following disclaimer.\r | |
11 | * 2. Redistributions in binary form must reproduce the above copyright\r | |
12 | * notice, this list of conditions and the following disclaimer in the\r | |
13 | * documentation and/or other materials provided with the distribution.\r | |
14 | * 4. Neither the name of the University nor the names of its contributors\r | |
15 | * may be used to endorse or promote products derived from this software\r | |
16 | * without specific prior written permission.\r | |
17 | *\r | |
18 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND\r | |
19 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE\r | |
20 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE\r | |
21 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE\r | |
22 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL\r | |
23 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS\r | |
24 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)\r | |
25 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT\r | |
26 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY\r | |
27 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF\r | |
28 | * SUCH DAMAGE.\r | |
29 | *\r | |
30 | */\r | |
31 | //__FBSDID("$FreeBSD: src/lib/libc/stdlib/rand.c,v 1.17.2.1.2.1 2009/10/25 01:10:29 kensmith Exp $");\r | |
32 | #include <LibConfig.h>\r | |
33 | \r | |
34 | #include <stdlib.h>\r | |
35 | \r | |
36 | static UINT32 next = 1;\r | |
37 | \r | |
38 | /** Compute a pseudo-random number.\r | |
39 | *\r | |
40 | * Compute x = (7^5 * x) mod (2^31 - 1)\r | |
41 | * without overflowing 31 bits:\r | |
42 | * (2^31 - 1) = 127773 * (7^5) + 2836\r | |
43 | * From "Random number generators: good ones are hard to find",\r | |
44 | * Park and Miller, Communications of the ACM, vol. 31, no. 10,\r | |
45 | * October 1988, p. 1195.\r | |
46 | **/\r | |
47 | int\r | |
48 | rand()\r | |
49 | {\r | |
50 | INT32 hi, lo, x;\r | |
51 | \r | |
52 | /* Can't be initialized with 0, so use another value. */\r | |
53 | if (next == 0)\r | |
54 | next = 123459876;\r | |
55 | hi = next / 127773;\r | |
56 | lo = next % 127773;\r | |
57 | x = 16807 * lo - 2836 * hi;\r | |
58 | if (x < 0)\r | |
59 | x += 0x7fffffff;\r | |
60 | return ((next = x) % ((UINT32)RAND_MAX + 1));\r | |
61 | }\r | |
62 | \r | |
63 | void\r | |
64 | srand(unsigned int seed)\r | |
65 | {\r | |
66 | next = (UINT32)seed;\r | |
67 | }\r |