It is currently Sat Dec 16, 2017 3:47 pm

All times are UTC - 7 hours





Post new topic Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Sat Oct 29, 2005 11:44 pm 
Offline
User avatar

Joined: Wed Nov 10, 2004 6:47 pm
Posts: 1845
Two questions about this mapper.

1) Considering there's a "VROM+VRAM" mode, I'm assuming games have 8k CHR-RAM in addition to CHR-ROM? Any games use this?


but more importantly...

2) IRQs were giving me problems in Sangokushi 2 -- as the game checks the IRQ counter by reading $5800 and loops until it gets $7F even -- however it checks a fixed number of cycles after setting the IRQ counter and running -- and it checks TOO LATE, and an IRQ has already fired by the time it reads.

Now from what I've been reading/researching, the IRQ counter counts up and ones it wraps from $7FFF->$0000, an IRQ is fired. This seemed to work for e, Sangokushi 2 issue aside. I've found that locking the IRQ counter at $7FFF... in addition to to firing an IRQ at that time fixes Sangokushi 2, which still providing the same function (seems hackish... but I can't imagine what else Sangokushi 2 is trying to do).

After skimming Nintendulator source to see how it does it (wraps $7FFF->0000) -- I tried out Sangokushi 2 in Nintendulator, and I wasn't surpised to find out it wasn't even getting to the title screen -- same problem I was having. Since the IRQ has already fired by the time the game reads $5800, it's getting $00 (or some other really low number) instead of $7F -- and since it loops until it gets $7F, the game never runs.

In addition to that problem.. I've tried Erika to Satoru no Yume Bouken. And if you go to the ?password? screen (second option from the title screen), input an invalid password, and press start, the book at the bottom shoots left for a frame or two. I haven't researched this, but I'd assume it's an IRQ problem (though it may not be... since I think CHR swapping is done in the IRQ routine, and the CHR looks fine when the book is pushed left). My emu does this... as does Nintendulator... and FCEUXD (haven't tried others though). Anyone know what's up with that?

Any clarification welcome and appreciated. ^^


Top
 Profile  
 
PostPosted: Sun Oct 30, 2005 7:58 am 
Online

Joined: Sun Sep 19, 2004 11:12 pm
Posts: 19352
Location: NE Indiana, USA (NTSC)
Disch wrote:
Considering there's a "VROM+VRAM" mode, I'm assuming games have 8k CHR-RAM in addition to CHR-ROM? Any games use this?

Dunno about N106 based games specifically, but if you're deciding whether or not to support VROM+VRAM at all in the design of a given NES emulator, then Rare's TQROM pinball games (Pinbot and High Speed) use this, and so do some Chinese games.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Oct 30, 2005 9:20 am 
Offline
User avatar

Joined: Wed Nov 10, 2004 6:47 pm
Posts: 1845
Yeah I meant N106 specifically. I already knew about TQROM.

Thanks though ;D


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: krzysiobal and 5 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