#include <stdlib.h>
#include <dist.h>

#define MASK	(0x7fffffffL)
#define NORM	(1.0/(1.0+MASK))

static long
rand32(void)
{
	unsigned long x;

	x = (rand()<<22) ^ (rand()<<11) ^ rand();

	return x & MASK;
}

double
frand(void)
{
	double x;

	do {
		x = rand32() * NORM;
		x = (x + rand32()) * NORM;
	} while(x >= 1);
	return x;
}