nsz Git - musl/blob - src/prng/drand48.c

   1 #include <stdlib.h>
   2 #include <inttypes.h>
   3
   4 uint64_t __rand48_step(unsigned short *xi, unsigned short *lc);
   5 extern unsigned short __seed48[7];
   6
   7 double erand48(unsigned short s[3])
   8 {
   9         union {
  10                 uint64_t u;
  11                 double f;
  12         } x = { 0x3ff0000000000000ULL | __rand48_step(s, __seed48+3)<<4 };
  13         return x.f - 1.0;
  14 }
  15
  16 double drand48(void)
  17 {
  18         return erand48(__seed48);
  19 }