Indirect addressing was almost as good as index registers. The instruction set supported both relative (to the current P register) and absolute. The original instruction set did not have a subroutine call instruction and could only address one bank of memory.
Indirect addressing was nearly as effective as index registers. The instruction set supported both relative (to the current P register) and absolute addressing. The initial instruction set lacked a subroutine call instruction and could only address one memory bank.