prod = uint64(v) * uint64(n)
			low = uint32(prod)
		}
	}
	return uint32(prod >> 32)
}

// exp2 generates n with probability 1/2^(n+1).
func (r *pcgRand) exp2() int {
	return bits.TrailingZeros32(r.uint32())
}

// bool generates a random bool.
func (r *pcgRand) bool() bool {
	return r.uint32()&1 == 0
}

// noCopy may be embedded into structs which must not be copied
// after the first use.