This is all good stuff!

BTW, the background here is for some reason I got interested in whether or not a TZA/TZX/TZY (transfer zero to...) would be useful. In Atari BASIC that would remove 132 #0's, about 1.5% of the total code. I expected to see lots of these, and when paging through them I was ...

I'm completely noob to 6502 ASM, so please be gentle...

I'm looking through the source code for Atari BASIC and the Atari base ROMs. I find a number of instances of something like ADC #0 or SBC #0 .

Am I correct in thinking these are being used as an analog of the non-existing CPA #0 ?

If so, why ...

I've ended up here while googling stuff related to BCD code on the 6502. I've seen a number of bits of code here for efficient processing of BCD, and that made me dream up a concept related to BCD floating point.

I'm trying to improve the loop performance of the infamously slow Atari BASIC, which ...