{name: "Ctz64NonZero", argLength: 1}, // same as above, but arg[0] known to be non-zero, returns 0-63
	{name: "BitLen8", argLength: 1},      // Number of bits in arg[0] (returns 0-8)
	{name: "BitLen16", argLength: 1},     // Number of bits in arg[0] (returns 0-16)
	{name: "BitLen32", argLength: 1},     // Number of bits in arg[0] (returns 0-32)
	{name: "BitLen64", argLength: 1},     // Number of bits in arg[0] (returns 0-64)