RE: [stella] RAM usage

Subject: RE: [stella] RAM usage
From: adavie@xxxxxxxxxx
Date: Wed, 21 Jun 2000 15:45:03 +1000
Unfortunately, no.
There are only 128 bytes of RAM (and they're in zero page) which you can
That is, although zero page is the area from $0 to $FF, only $80 to $FF is
actually populated with RAM.
And worse still, the stack uses that very same 128 bytes - it usually works
from the top ($FF) down.
So, you don't really have 128 bytes anyway.  you have 128 bytes LESS the
amount of stack space you require.  Too many subroutines, and you wipe out
your variables.  This is what I love about the 2600 :)

-----Original Message-----
From: owner-stella@xxxxxxxxxxx [mailto:owner-stella@xxxxxxxxxxx]On
Behalf Of Glenn Saunders
Sent: Wednesday, June 21, 2000 2:55 PM
To: stella@xxxxxxxxxxx
Subject: Re: [stella] RAM usage

At 12:29 AM 6/21/2000 -0400, you wrote:
>The 128 bytes of RAM are inside the RIOT..."RAM,I/O,TIMER"
>Yes the RIOT RAM is mapped into the 6507's address space at $80-$FF.
>The TIA registers are mapped into the other half of zero page at $0-$7F.

Zero page is 256 bytes, right?  So this would not conflict with the 128 
byte mirror of RIOT RAM exposed through zero page?

Glenn Saunders - Producer - Cyberpunks Entertainment
Personal homepage:
Cyberpunks Entertainment:

Archives (includes files) at
Unsub & more at

Archives (includes files) at
Unsub & more at

Current Thread