for _, n := range mulBenchSizes {
		if isRaceBuilder && n > 1e3 {
			continue
		}
		b.Run(fmt.Sprintf("%d", n), func(b *testing.B) {
			benchmarkNatMul(b, n)
		})
	}
}

func TestNLZ(t *testing.T) {
	var x Word = _B >> 1
	for i := 0; i <= _W; i++ {
		if int(nlz(x)) != i {
			t.Errorf("failed at %x: got %d want %d", x, nlz(x), i)
		}
		x >>= 1
	}
}

type shiftTest struct {