2 * random.c - functions to get random values
12 /* global and extern variables */
15 extern u32 *rand_buf,*rand_current;
17 /* return random integer between 0 - max-1 */
20 if(rand_current>=rand_buf+(RAND_BUF_SIZE/sizeof(u32)))
22 printfd("debug: reading new random bytes\n");
23 if(read(random_fd,rand_buf,RAND_BUF_SIZE)!=RAND_BUF_SIZE)
25 puts("failed reading 1 mega bytes of random data");
28 rand_current=rand_buf;
30 /* cells numbered 0...max-1 */
31 return((u32)(*(rand_current++)*(max*1.0/URAND_MAX)));
34 /* get z value (linear growth of probability with depths) */
35 u32 rand_get_lgp(int slope,int start,u32 z_max)
39 weighted_sum_z=z_max*start+slope*gr;
40 z=rand_get(weighted_sum_z)+1; /* +1 as rand_get returns values 0...max-1 */
46 return(i-1); /* return values 0...z_cell-1 */