for i := 0; i < b.N; i++ {
			x.shl(x, 0)
		}
	})

	b.Run("Shr", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			var z nat
			z.shr(x, 0)
		}
	})
	b.Run("ShrSame", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			x.shr(x, 0)
		}
	})
}

type modWTest struct {
	in       string
	dividend string
	out      string
}