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 use. 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 :) A -----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: http://www.geocities.com/Hollywood/1698 Cyberpunks Entertainment: http://cyberpunks.uni.cc -- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/ -- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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