6502 documentation

Vegenad · Post by **Vegenad** » Tue Sep 18, 2007 12:42 pm

Hi.

I plan to start the writing of a NES emulator soon and wondered if anybody could point me towards a good book (or online resource) on the 6502 processor (how the interrupts work etc).

Thanks for any ideas you can give me.

gannon · Post by **gannon** » Tue Sep 18, 2007 1:23 pm

http://nesdevwiki.org/

never-obsolete · Post by **never-obsolete** » Tue Sep 18, 2007 2:23 pm

i bought "Programming the 6502" by Rodnay Zachs and it was pretty good. i got it on amazon or somethin like that for about $10 total.

No Carrier · Post by **No Carrier** » Tue Sep 18, 2007 2:36 pm

never-obsolete wrote:i bought "Programming the 6502" by Rodnay Zachs and it was pretty good. i got it on amazon or somethin like that for about $10 total.

Same here.

NC

Josh · Post by **Josh** » Tue Sep 18, 2007 8:51 pm

The Commodore 64 Programmer's Reference Guide is a good source as well. One thing you should keep in mind is that the NES CPU does not have decimal mode, so any references to decimal mode in 6502 documentation should be ignored. (You can set and clear the flag with SED/CLD, but it does nothing.)

What specifically did you need to know about interrupts?

Disch · Post by **Disch** » Wed Sep 19, 2007 8:36 am

As far as reference pages go... to this day I still use obelisk:

http://www.obelisk.demon.co.uk/6502/reference.html

One of the few docs that are actually easy/quick to navigate and is 100% error free.

For detailed (advanced) operation of each instruction, the charts at the bottom of this doc are a big help:

http://nesdev.com/6502_cpu.txt

Vegenad · Post by **Vegenad** » Mon Sep 24, 2007 12:14 pm

Thanks for all the references.

Very much appreciated.

What specifically did you need to know about interrupts?

Nothing in particular to be honest. Just my feeble attempt at trying to clarify the kinds of things I wanted any texts to help me with

aphex · Post by **aphex** » Thu Apr 22, 2010 5:49 pm

(I'm turning into a prolific necroposter

, oh well)

Resources I use
http://nocash.emubase.de/everynes.htm#c ... oprocessor
http://www.atarimax.com/jindroush.atari.org/aopc.html
http://www.obelisk.demon.co.uk/6502/reference.html
http://www.llx.com/~nparker/a2/opcodes.html

Enjoy

Disch · Post by **Disch** » Thu Apr 22, 2010 8:02 pm

(I'm turning into a prolific necroposter Confused, oh well)

You should shake that habit.

This thread is 3 years old. He either completed his emu by now, or has given up on it entirely.

How do you even FIND these old threads? Are you like reading threads on page 38? Why?

aphex · Post by **aphex** » Thu Apr 22, 2010 9:36 pm

How do you even FIND these old threads? Are you like reading threads on page 38? Why?

I was just reading my way through the posts, but I have read all 18 pages now, so i'm done. This is simply because this forum contains so much useful information and has answered many of my question that I had.

Post by **tepples** » Fri Apr 23, 2010 4:10 am

Disch wrote:This thread is 3 years old. He either completed his emu by now, or has given up on it entirely.

How do you even FIND these old threads? Are you like reading threads on page 38? Why?

For the benefit of people who use the search button. A lot of external links will have gone dead between when a post is made and when a user ends up on it through a search.

Zepper · Post by **Zepper** » Fri Apr 23, 2010 8:17 am

Disch wrote:This thread is 3 years old. He either completed his emu by now, or has given up on it entirely.

How do you even FIND these old threads? Are you like reading threads on page 38? Why?

- I disagree too, old topics shouldn't be revived... but anyway, I'm not a lawyer.

Bregalad · Post by **Bregalad** » Fri Apr 23, 2010 8:47 am

For the benefit of people who use the search button. A lot of external links will have gone dead between when a post is made and when a user ends up on it through a search.

By the way the search button here completely sucks. If you want to search ONE word it's okay, but if you want more than one word it will give you all pages that have at least one word of the one you search, which SUCKS. Each time I want to find an old thread I have to prepare a whole afternoon to do that, and this is bad.

Post by **tepples** » Fri Apr 23, 2010 8:58 am

Try clicking the "Search for all terms" radio button. Or use the words followed by site:nesdev.com in a Google search.

tokumaru · Post by **tokumaru** » Fri Apr 23, 2010 9:07 am

Zepper wrote:- I disagree too, old topics shouldn't be revived... but anyway, I'm not a lawyer.

I think it's OK to revive threads when you have something interesting to say that is highly on topic. Otherwise make a new thread or don't say anything at all.

Answering a question that was made several years ago hardly justifies it, because the person who asked probably doesn't even care anymore. And I don't think it even helps other people with the same problem, because if there were such people they'd have revived the thread themselves to re-ask the question or created a new thread about it already, and then it would be appropriate to answer.

I do understand though what it's like to find a place with interesting discussions that have happened long ago and you weren't around to participate. But still, reviving topics nobody cares about anymore is annoying for people who have been around longer. Interesting discussions will happen again, don't worry, just stick around and keep the resurrecting to a minimum.