int irbit1(unsigned long *iseed)
{
	unsigned long newbit;

	newbit =  (*iseed >> 17) & 1
		^ (*iseed >> 4) & 1
		^ (*iseed >> 1) & 1
		^ (*iseed & 1);
	*iseed=(*iseed << 1) | newbit;
	return (int) newbit;
}