Z:gnu-www-ja-stallman-kth--df9cb8-Problems can also arise with i/en

Problems can also arise with index registers. If you're trying to index by something, then most of the time that code will become invalid if the index quantity is in memory, except in a few cases on some machines where you can it with indirect addressing. In the cases when you're doing auto-increment on an index register you may have to copy the value into a register, do the instruction, and then copy the incremented value back to the memory slot where it really lives.