I've just got this working: it's an extension of Nick Morgan's 6502js simulator(*) to support 16bit and 32bit variants(*). There's a minimal assembler and disassembler: you can also use DCB directives to load a binary in.

See http://biged.github.com/6502js/ which should look like this:


There's more to do on the assembler: it doesn't support full expressions for any more cases than I needed for the test. But I know how to add that.

Here's a test program:


You'll only be able to assemble this successfully in 16bit or 32bit mode.

Comments welcome.

Cheers
Ed

(*)16 and 32bit variants of nmos6502 which I think of as 65Org16 and 65Org32.

(*)6502js is the simulator found in easy6502

I just committed some fixes. The emulator now runs Nick's snake game demo in 8bit, computes pi with the above program in 16bit, and with a few changes the same program runs in 32 bit:
- initialise S to 1ff or so, otherwise the stack sits over the I/O locations
- change 16 to 32 in two places.

This might be the first program to run on the 65Org32!

(Edit to fix typo: thanks Jeff)

Looks good, BigEd!

I wanted to say something as well when I first read your initial post BigEd. I know emulators like VICE, which can emulate the C64, and I know Mikal Kowalski's assembler for the PC. These are excellent tools for 6502(c) development on the PC. I'm just not sure where to place your development of this PC software you have developed for the 65Org16 core? Forgive my questions please if they're ignorant please.

_________________
65Org16:https://github.com/ElEctric-EyE/verilog-6502

I don't want to speak for BigEd, but I can use my simulator effort as potentially an example.

I had an itch to dabble with the "low level" coding, and I thought maybe building a classic 8-Bit machine, like a Z80 or 6502, would be interesting. But when I thought it all through, the machine itself didn't interest me as much as trying to write something for one.

So I scratched my itch by writing a 6502 simulator, and, because I was on a Mac, and not happy with what I found, I ended up writing a 6502 assembler as well.

My virtual 6502 machine is little more than a CPU with 64K of RAM and a serial port (I should say "character I/O"). No ROM, no monitor, nothing else. But its enough to get Fig-Forth up and running (I have rudimentary disk I/O working as well).

But it's enough to do 6502 development. To give someone a taste of what it's like to write low level code for these kinds of machines. And at the same time, it's not burdened with assumptions. It's not a C64/Apple/Atari, so all of the zero page is mine to abuse, for example.

By creating a simulator for the 65Org16/32, a simple one that happens to have a console as well as some graphics, it lets someone "taste" the -16/32 CPU. See what it's like. "What would it be like to have a 16b Accumulator?" Get your hands dirty without have to do a lot of work.

So, I think it's exciting in its way. It makes the CPU seem more real, and lets the designers start playing with new instructions, or whatever, "for real", rather than as thought experiments or expensive hardware (time and/or $$$) assignments. Now they can write real code and see how it handles.

Good stuff.

Thanks whartung - that's pretty close. Demonstrating and allowing for exploration of these two architecture extensions was the main idea. Also, it's handy to have a way to run short code sequences. It would take more work to make this approach the scope of Michal's tool, but this one supports our new CPUs and is open source.

(Note that the emulator is a browser page, not a PC program. You can download the source and use it purely locally, which is good if you're extending or fixing it, or you can just point your browser at http://biged.github.com/6502js/ No need to install anything.)

Cheers Ed

Ah, no hardware! I get it, thanks.

Nice skills BigEd, keep the 65Org32 dream alive!

_________________
65Org16:https://github.com/ElEctric-EyE/verilog-6502

It didn't used to be available, but Michal Kowalski released the source of his program a while back.

_________________
- Mike Naberezny (mike@naberezny.com) http://6502.org

Goodness, I had no idea. It's v1.2.6 so we need to check what's missing wrt 1.2.11, and how to build it.
Cheers
Ed

I just fixed a bug with ROR in 32-bit mode - this mode needs some care in JavaScript because it pretends to have 32bit integers for bit operations but is actually using floats.

Here's my test program, which runs in all sizes: 8, 16 and 32 bit:
There's a pointless loop to slow things down to the point where you can see what's happening.