Hi, I've been working on a 6502 emulator that works on unix/linux and windows boxes. I don't know if it works on anything else ATM.

Anyway, I was wondering if anyone would be willing to have a look at it and try and find any bugs it may have or make suggestions for useful features?

Currently it requires a c compiler, but I can make a compiled version available if anyone wants one.

It's available at http://idiocy.org/programs/6502.html

Thanks!

It sounds like you mean a software simulator and not a hardware emulator. It that right? In other words, you can run your program on the PC and watch the register contents and so on, but not actually have a piece of hardware plugged into the 6502 socket on the board, running it the way the normal processor would but with the ability to see what's going on inside.

Is it strictly for 6502, or also 65c02? Will it run on a DOS machine without Windoze? I'm interested, but I can't promise when I would use it and get you the feedback to you're looking for.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Yeah, that's right, you can run your programs and watch the memory and registers and so on.

It should run on DOS without windows, currently it has no graphical frontend for any platform.

Oops, forgot to say, it's only the 6502, but I could probably upgrade it to support the 65c02 sometime, it's just a matter of finding what's different.

Um, while i suspect that your effort is a great learning experience, did you look at any of the existing code in the PD which does this already?

I'd look at the processor core code of existing C64 & Apple II emulator code. It would be a darn sight easier to add a single step & register window to AppleWin than to code brand-new a 6502 emulator.

And I know for a fact the processor core code for AppleWin is stand-alone - so at a last resort, you could use it separately with a new front-end.

WizWom

Well, I'm afraid it's been done now. If you're not interested that's fine, but I just figured it would perhaps be useful to someone.

I wouldn't be too influenced by the work that's gone into emulations of existing hardware systems. A good stroke-by-stroke simulator of the 6502/65C02 processor, independent of its hardware environment, is a worthy goal, particularly if you simulate it precisely. T

he obvious next step would be to include an I/O routine to the EPP on the PC to drive an emulation pod. That would be quite straightforward and, in fact, can be accomplished with a single CPLD costing just a few dollars and programmable with free software in combination with a download cable you can build at home, since the pinout would be predetermined. Depending on how the EPP is implemented in the PC, it's conceivable to run the emulation at nearly real-time for a 1 MHz part. It would, however, require that the part be simulated at the hardware level rather than just a once-over lightly in register transfer language.

A display routine wouldn't really be needed, but might provide valuable insight.

What's interesting is the dummy cycles the processor goes through while executing an instruction. In some cases there are locations read that aren't used, which can have surprising consequences.

Let me know if there's any information you need to take this next step. In the meantime, I'll see where I can find an UN-TGZ utility so I can look at your code.

Uli

You will find a decompressor at http://www.gzip.org and a tar extractor at ftp://ftp.gnu.org/gnu/tar/

I've already gotten it from

<http://www.isjm.com/tst/download.htm#untgz>

though it may not be the same thing.

Uli

Probably not. I've only used/trusted gzip and GNU tar, which are what I pointed to you, the "official" utilities for extracting .gz and .tar archives (a .tgz or .taz archive is a .tar.gz archive). By the way, gzip is the same exact version now as it's been since 1993...

ULI_E wrote:
I wouldn't be too influenced by the work that's gone into emulations of existing hardware systems. A
good stroke-by-stroke simulator of the 6502/65C02 processor, independent of its hardware
environment, is a worthy goal, particularly if you simulate it precisely.

What I'd like to see is a 65816 emulator, for either the Intel or PowerPC platforms.

Exegete AKA Roy Miller
Faith Orthodox Presbyterian Church
Apple ][ forever!

Heh, a good DOS or Windows IIgs emulator'd be nice too...something like Bernie ][ the Rescue...

The point of such an emulator should be obvious... a PowerPC or Pentium based turbo card for a 6502/10/816 based computer, utilizing all of the resources of the host, like the sound/video of an Atari, Commodore, or //GS.

Exegete AKA Roy Miller
Faith Orthodox Presbyterian Church
Apple ][ forever!

Well, even if I'm repeating myself, A 65816 is NOT a 6502.

Uli

Trying to follow this thread, I'm wondering if you mean "simulator", "emulator", or if both are getting discussed. The simulator is software that shows you what the program for (typically) another processor is doing. An emulator is actual hardware that plugs into the processor's socket in the target computer; but beyond just being an actual hardware microprocessor, it gives you windows into the insides, so you can see what's happening in the actual internal registers. The emulator normally plugs into the actual circuit board of interest and uses the board's own I/O and memory. I has ribbon cables to the host computer.

Very good ones of both are available commercially. Check WDC's list of available hardware and software development tools.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?