6502 simulator in 6502

6502 simulator in 6502
by tepples on 2012-04-28 (#93036)

I'm aware of two 6502 simulators in 6502 assembly language:

The STEP subroutine at FA43 in the Apple II ROM
The one in the CopyNES BIOS

Are there any others?

by tokumaru on 2012-04-28 (#93048)

And what exactly would be the purpose of simulating a 6502 in 6502 assembly?

by cpow on 2012-04-28 (#93054)

tokumaru wrote:
And what exactly would be the purpose of simulating a 6502 in 6502 assembly?

Isn't there a Turing-ism or something along the lines of "any machine can simulate any other machine, even itself". Or maybe it was a language-ism...any language can be used to construct any other language, even itself. Gah! I'm not remembering my college classes too well am I.

by tepples on 2012-04-28 (#93056)

How about "because I can"? Or "because I want to make an environment allowing single stepping through 6502 code on any platform that can run an NES emulator, even if a debugger hasn't yet been ported to it"?

by tokumaru on 2012-04-28 (#93058)

tepples wrote:
"because I want to make an environment allowing single stepping through 6502 code on any platform that can run an NES emulator, even if a debugger hasn't yet been ported to it"

Since there are a lot of things that can't be debugged that way, I imagine this is basically to inspect the logic? How would you control such a debugger while the program is running? If the emulator doesn't have a debugger, will you output debug information to the screen?

by LocalH on 2012-04-29 (#93088)

There's The Incredible KIMplement for the Commodore 64, emulating the MOS KIM-1. It doesn't handle the undocs, though.