Previous Thread
Next Thread
Print Thread
The mysteries of N64 microcodes #117055 03/18/20 08:44 AM
Joined: Aug 2008
Posts: 89
C
Christina Offline OP
Member
OP Offline
Member
C
Joined: Aug 2008
Posts: 89
I found this website with a lot of information about N64 code obscurities and I'm bringing to this forum for everyone interested.
I'm thinking of any of this information can help the devs in any way...

https://olivieryuyu.blogspot.com/

Re: The mysteries of N64 microcodes [Re: Christina] #117056 03/18/20 02:48 PM
Joined: Dec 2011
Posts: 170
Alegend45 Offline
Senior Member
Offline
Senior Member
Joined: Dec 2011
Posts: 170
It won't. MAME uses RSP LLE, not HLE, meaning that it emulates the microcode by actually running it. Therefore this information is, for the most part, useless to us AFAIK.

EDIT: Oh wait, this is about optimizing RSP code to run faster anyway, which has no relevance to actually emulating the RSP in the first place.

Last edited by Alegend45; 03/18/20 02:52 PM.
Re: The mysteries of N64 microcodes [Re: Christina] #117057 03/18/20 03:08 PM
Joined: Mar 2001
Posts: 16,473
R
R. Belmont Offline
Very Senior Member
Offline
Very Senior Member
R
Joined: Mar 2001
Posts: 16,473
It's interesting for doing HLE as well, but yeah, for what we do it's largely not applicable.

Re: The mysteries of N64 microcodes [Re: Alegend45] #117058 03/18/20 03:22 PM
Joined: Jun 2001
Posts: 418
O
Olivier Galibert Offline
Senior Member
Offline
Senior Member
O
Joined: Jun 2001
Posts: 418
Originally Posted by Alegend45
EDIT: Oh wait, this is about optimizing RSP code to run faster anyway, which has no relevance to actually emulating the RSP in the first place.


Just to be contrary, optimized code tends to use more possibilities of a cpu/dsp, so throughly commented optimized code can be rather useful for debugging.

Re: The mysteries of N64 microcodes [Re: Olivier Galibert] #117059 03/18/20 07:56 PM
Joined: May 2009
Posts: 1,840
J
Just Desserts Offline
Very Senior Member
Offline
Very Senior Member
J
Joined: May 2009
Posts: 1,840
Originally Posted by Olivier Galibert
Originally Posted by Alegend45
EDIT: Oh wait, this is about optimizing RSP code to run faster anyway, which has no relevance to actually emulating the RSP in the first place.


Just to be contrary, optimized code tends to use more possibilities of a cpu/dsp, so throughly commented optimized code can be rather useful for debugging.


And to be equally contrary, none of this seems to really be "optimizing" anything, more just "I think the microcode should work this way, so I'll make it work that way".

Re: The mysteries of N64 microcodes [Re: Christina] #117060 03/18/20 09:03 PM
Joined: Apr 2010
Posts: 50
H
Happy Offline
Member
Offline
Member
H
Joined: Apr 2010
Posts: 50
Having disassembled many different N64 microcodes, I find it sort of interesting. All the microcodes have to deal with the issue of IMEM and DMEM being very limited in size, so there are a few different techniques to stream data in and out. However with respect to MAME, I think more of the issues with MAME's N64 emulation of the RSP are related to timing issues and synchronization with the rest of the N64 components..

Also you can optimize the RSP code all you want, but the RDP and memory bandwidth are still going to be major factors in the overall performance that you can't do much to optimize.

Last edited by Happy; 03/18/20 09:10 PM.

Who's Online Now
2 registered members (Lord Nightmare, 1 invisible), 45 guests, and 3 spiders.
Key: Admin, Global Mod, Mod
ShoutChat Box
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Forum Statistics
Forums9
Topics8,764
Posts115,179
Members4,889
Most Online890
Jan 17th, 2020
Powered by UBB.threads™ PHP Forum Software 7.7.3