Sometimes it can actually be more efficient, since more bits are wasted with indexing. Random example: 1234 opcodes, 12 registers. 1234 * 12^3 = 2132352 (22

Sometimes it can actually be more efficient, since more bits are wasted with indexing. Random example: 1234 opcodes, 12 registers. 1234 * 12^3 = 2132352 (22 bits) 1234 is 11 bits, 12 is 4 bits 11 + 3*4 = 23 bits so in this case, using indexes is less efficient by one bit per instruction.