6 A "32-bit Multiply with carry" random number generator.
11 #include "utl_random.h"
14 /* Initialize random number generator with two integer variables */
16 void utl_randomInit(RND_CTX * rndContext, unsigned int xi, unsigned int ci)
19 * Choose a value for 'a' from this list
20 * 1791398085 1929682203 1683268614 1965537969 1675393560
21 * 1967773755 1517746329 1447497129 1655692410 1606218150
22 * 2051013963 1075433238 1557985959 1781943330 1893513180
23 * 1631296680 2131995753 2083801278 1873196400 1554115554
25 rndContext->a = 1655692410;
26 rndContext->x = 30903;
31 rndContext->ah = rndContext->a >> 16;
32 rndContext->al = rndContext->a & 65535;
35 /* Initialize random number generator from time */
37 void utl_randomInitTime(RND_CTX * rndContext)
45 utl_randomInit(rndContext, a, b);
48 /* Returns random numbers */
50 unsigned int utl_random(RND_CTX * rndContext)
54 xh = rndContext->x >> 16, xl = rndContext->x & 65535;
55 rndContext->x = rndContext->x * rndContext->a + rndContext->c;
57 xh * rndContext->ah + ((xh * rndContext->al) >> 16) +
58 ((xl * rndContext->ah) >> 16);
59 if (xl * rndContext->al >= (~rndContext->c + 1))
62 return (rndContext->x);