Re: Scrolling HGR Screen Up 8 Lines

[dempson@actrix.gen.nz (David Empson)]

Christer Ericson <christer_ericson@playstation.sony.nospam.com> wrote:

> I used to wish that indirect-comma-X had been post-indexed just
> like indirect-comma-Y. IMO, it's such a useless addressing mode.
> Did anyone ever find a really good use for it? (I mean other than
> with X as constant.)

Its intended purpose appears to be indexing into a table of pointers,
which must be located in zero page.  It isn't often that you need to
access a single byte at the destination address of a pointer, however.

This addressing mode makes a lot more sense when used with JMP and JSR
(on the 65C02 and 65816 respectively), since you are then using X as an
index into a table of function pointers.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand