Rob Mundschau wrote::
> This is my first post, so let me start by introducing myself. My name is
> Rob Mundschau. I never programmed for the 2600 before, but I do have
> considerable experience programming the Commodore 64. Lately I have grown
> interested in the 2600 Homebrew scene, and I hope to make some games.
Welcome Rob!
> I have been browsing the archives, and I haven't found any mention of
> technique I know of for implementing a jump table. Excuse me is this was
> mentioned before, and I missed it. The smallest implementation I saw on the
> list so far is:
> snip
> Using the PHA instructions saves 2 bytes of ROM. The RTS takes one more
> clock cycle than the indirect JMP instruction so the routine takes one clock
> more overall.
The little advantage of the JMP() version is, that it doesn't need extra stack RAM. Instead you can re(!)use two other currently unused bytes (e.g. a pointer). And too little RAM is always a problem. :-)
Have?fun!
Thomas
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