Re: [stella] Stella sequencing

Subject: Re: [stella] Stella sequencing
From: Erik Mooney <emooney@xxxxxxxxxxxxxxxx>
Date: Mon, 4 Jan 1999 14:25:55 -0500 (EST)
> It's decremented.  This is why you allocate your own scratch variables
> ascendingly ($80 and up), whilst you have the stack "crawling" downwards from
> $FF, and as the programming guide mentions "hope they don't meet" :)
> 
> On *ALL* 6502-derived CPUs (aside from the 16 and 32 bit evolved 65816 etc), the
> stack register is only 8-bits wide.  On the Apple ][, it was located at
> $100...$1ff if memory serves.

Technical nitpick: the stack can also be accessed at $100...$1ff on the
2600, or in fact at any binary address xxx0xxxx00000000 through
xxx0xxxx11111111.

> Well, in the aspect of this question of yours, since emulators probably provide
> "unlimited" resources, such as RAM (if need be), it may obscure (or even cover
> up) blatant programming mistakes that would seize fast on a real VCS.  (I
> actually don't have the data to say for certain, however, since so many
> incarnations of VCS runtime envrionments exist, I imagine Stella and other
> emulators "can provide" tons more than 128 bytes of RAM and 4k of ROM, etc.

Most of the emulators do support up to 32k bankswitched ROM images, but
then so does the real VCS.  But they won't supply any more than that or
128 bytes of RAM to the program code - that's the point of emulation.


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