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Last updated on Oct-18-2019 Download

opcode guide with cycle count?

opcode guide with cycle count?
by on (#44117)
I think I saw somewhere a 6502 opcode guide with how many cpu cycles each one spent, but I can't find it now.
Is there any? can you point it out? thanks!

by on (#44118)
http://www.6502.org/users/andre/petinde ... /64doc.txt

by on (#44121)
i like this one :) http://nesdev.com/6502.txt

by on (#44130)
ThanksĀ² !

by on (#44134)
Beware that 6502.txt has many critical typos (like the wrong opcode listed in places). This is why I don't like to recommend it to people as a reference doc, even though it does a good job of explaining things.

I'd recommend you use obelisk as a reference to double check against 6502.txt:

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

I've been using it for a primary reference for years now and I can assure it is error-free.

Though if you want details about what the CPU is doing on each cycle -- it doesn't get better than this doc (scroll down to near the end):

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

That's only really useful for emulator devs, though.

by on (#44174)
i like 6502.txt for the way it i laid out.. didn't know about the errors though :oops:

actually seeing the description of each clock cycle is cool though, makes it easier to remember how many cycles each operation takes

by on (#44181)
Thanks disch! they are great.

by on (#44612)
http://www.6502.org/tutorials/6502opcodes.html

Easy to use, and even includes info on what each instruction does.

by on (#44613)
^ yeah i found that one recently and i have to say it's quite nice