Long time ago, but by far the worst for me was when I inherited some code that a previous programmer had done. Every variable was a breakfast item. So if biscuit>bacon then scrambledeggs=10. Shit like that. It was a nightmare and luckily I only had to deal with it infrequently.

It has been a while for me, but I think you are going to have to do this all manually. The 6502 is 8bit and you can’t load a 16bit word into the accumulator. Load A $lineL, increment A, store A, then compare it to 0 and beq a routine to increment $lineH, and then also compare that to your ending number. If you are wanting to end in 0x05FF you might also have to put in a compare when $lineL gets to 05 to see if $lineH is FF. I would have to find my atari books, or do some googling.

Edit: see my reply.