6502.org

Hello. As a 6502 newbie, one of the first things I have done is study the op-codes. As a result, I have an op-code chart that I would like to share. How do I do that?

Hi, and welcome! This kind of thing might be helpful, and the page is quite attractively done. Can I encourage you to add the CMOS instructions and addressing modes. The old limited NMOS 6502 has been out of production for decades, but the CMOS continues on with no end in sight, with a lot of benefits. The many improvements are summarized at http://wilsonminesco.com/NMOS-CMOSdif/ . You could put their text in a different color if you want to show that they're not in the old NMOS set.

I did not proofread the whole thing, but as I was trying an example of how to use it, I looked at op code $64 which is STZ ZP, but occupying its spot is ADC ZP which should be $65 instead. As I was trying to figure it out further, I see ASL ZP is at 05 which should be ORA ZP, and ASL ZP,X is $15 which should be ORA ZP,X. The ones with lsn=6 are missing, even though they're in the NMOS, unlike the ones with lsn=7, B, and F.

Thanks.

Thank you for taking an interest. Looking at the chart again and comparing it to my reference document, I do see some flaws---e.g., incorrect op-codes---(that's what I get for working on this in the wee hours of the morning!)---thank you for pointing that out.

Consider the original file post a draft, then.