It is currently Mon Oct 15, 2018 8:38 am

All times are UTC - 7 hours





Post new topic Reply to topic  [ 19 posts ]  Go to page Previous  1, 2
Author Message
 Post subject:
PostPosted: Sat Feb 11, 2006 5:48 am 
Offline
User avatar

Joined: Sat Jul 09, 2005 6:03 am
Posts: 85
So getting the CPU and ROM values to match before bank switching with $8000/$8001 will prevent the bus conflict altogether. Right?


Top
 Profile  
 
 Post subject:
PostPosted: Sat Feb 11, 2006 6:15 am 
Offline
User avatar

Joined: Fri Nov 12, 2004 2:49 pm
Posts: 7546
Location: Chexbres, VD, Switzerland
If by "CPU" value you mean the value that the CPU writes to $8000-$ffff (usually the Accumulator value, but it can actually also be X or Y register), so yeah, that's right.

_________________
Life is complex: it has both real and imaginary components.


Top
 Profile  
 
 Post subject:
PostPosted: Sat Feb 11, 2006 8:00 am 
Offline

Joined: Thu Sep 15, 2005 9:23 am
Posts: 1194
Location: Behind you with a knife!
Bregalad wrote:
...usually the Accumulator value, but it can actually also be X or Y register), so yeah, that's right.


Or any RMW opcode (ASL, LSR, INC, DEC, ROL, ROR).

_________________
http://www.jamesturner.de/


Top
 Profile  
 
 Post subject:
PostPosted: Sat Feb 11, 2006 8:12 am 
Offline
User avatar

Joined: Fri Nov 12, 2004 2:49 pm
Posts: 7546
Location: Chexbres, VD, Switzerland
Well...
ASL and LSR could work with $00, to write $00, but anyother value will output bus conflicts.
INC and DEC can ONLY lead to bus conflicts.
ROL and ROR would, well, work with $00 and carry clear OR with $ff and carry set, but that's rather crazy.
So yeah, a game could avoid having lda #$00; sta BusConflictZero, but instad have asl BusConflictsZero to switch bank zero, while crazy, it would in theory works.

_________________
Life is complex: it has both real and imaginary components.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 19 posts ]  Go to page Previous  1, 2

All times are UTC - 7 hours


Who is online

Users browsing this forum: Google [Bot], unregistered and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group