Anybody thought of a light port of Applesoft?

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Anybody thought of a light port of Applesoft?

Postby vbriel » Apr Tue 22, 2008 10:46 pm

I was wondering if anybody had ported Applesoft yet? Mostly just the I/O needs converting. It would make a nice floating point basic.

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Postby Aaron Teeling » Apr Wed 23, 2008 7:29 am

I would be interested, but I lack the skills.

Would this be the first step into creating a Apple II replica?
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Postby vbriel » Apr Wed 23, 2008 7:55 am

I don't know. Since the rev 0 board is done, why? If I were to do a II kit it would be to reduce chip count (AKA IIe) but I just don't see doing it. Someone has done it in FPGA and exact replica so, I just don't see doing it. If there were some useful unique angle to a II replica, like super small board for laptop that would be good but the FPGA boards are already small.

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Postby Aaron Teeling » Apr Wed 23, 2008 9:10 am

Vince,

I respectfully disagree. Just because it's been done before doesn't mean it can't be done the Vince Briel way. The Apple 1 has been done several times but the Replica 1 is by far the most popular and I think that is a tribute to your improvement on the design. The expansion cards are pretty cool too and in the end, for a rock bottom price, the hobbyist gets the most out of their investment.

You had talked about adding a VGA/color graphics option to the Replica 1.. isn't this the same reasoning Woz followed to developing the Apple II?
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Postby minimicrite » Apr Sun 27, 2008 11:14 pm

I'd be up for a laptop-scale Apple II board. Even better, throw an integrated mass storage device (SD, CF, etc.) in for good measure. Just add a small keyboard, small display, battery, and you've got one fantastic portable Oregon Trail machine.
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Re: Anybody thought of a light port of Applesoft?

Postby cowgod » May Mon 05, 2008 1:50 pm

vbriel wrote:I was wondering if anybody had ported Applesoft yet? Mostly just the I/O needs converting. It would make a nice floating point basic.

Vince


I've been messing around with this for a few days and managed to get a partially-working version of Applesoft running (under the java emulator). There are definitely a lot of problems to work out but simple things like PRINT and INPUT are working.

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Postby vbriel » May Mon 05, 2008 4:54 pm

You won't get everything working, but if the basic FP basic works, that would be nice. Keep us updated with things like bugs, and what works!

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Postby dragos » May Mon 05, 2008 9:36 pm

I would buy a ii kit!!!! that would be a great idea, in my book. I have to agree, that while it may have been done, it was not done like your projects.

I fully enjoyed assembling and now playing with my micro-kim and will certainly be ordering a replica 1
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Postby cowgod » May Tue 06, 2008 1:04 am

vbriel wrote:You won't get everything working, but if the basic FP basic works, that would be nice. Keep us updated with things like bugs, and what works!

Vince


I've got more commands working now. I haven't tested them all yet but everything I tried so far is working with the exception of CALL.

I took out all the stuff that can't be done on the Apple-1/Replica-1 like graphics and the cassette I/O stuff. I also removed a few other commands to make everything fit into 8K of ROM.

Now I'm working on a bug that is causing FP math to be wrong. For example, PRINT 1/2 prints ".50390625". Some bits must be getting flipped somewhere, but I haven't tracked it down yet.

Here's a screenshot from the emulator:
Image

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Postby vbriel » May Tue 06, 2008 1:13 am

Can you compile it a 6000-7FFF, I'd like to try it on a replica 1.

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Postby cowgod » May Tue 06, 2008 12:37 pm

I was targeting $E000-$FEFF with the intent of programming a new ROM for my replica, but it should be possible to load it in RAM as well with some modification.

Applesoft assumes it is running from ROM and that all RAM is available for its use. The initialization routines would have to be changed to limit the amount of memory used to keep it from clobbering itself. I want to try and get it into a mostly-working condition first, then it shouldn't be a big deal to build both a ROM and RAM version.

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Postby vbriel » May Tue 06, 2008 9:17 pm

E000 would be fine or a .bin file to program a EEPROM. I'm wondering what is causing the integer variable mess?

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Postby cowgod » May Tue 06, 2008 10:00 pm

Well, I just pulled the ROM out of my replica and re-programmed it with the Applesoft image.... it works! It looks like the math problem is actually some kind of bug in the emulator. I double-checked all the code against the unmodified version and I don't see anything that would cause this problem, and it works fine on the real hardware. Weird.

Here's a .bin file you can try out, it's set up with the woz monitor at the usual place and Applesoft at $E000. http://cowgod.org/replica1/applesoft/applesoft-r1.bin

And here's a photo of it running on my replica:

Image

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Postby vbriel » May Tue 06, 2008 11:01 pm

Nice work Tom. I can't wait to try it out. Actually, I'm going to burn an EPROM now!

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Postby vbriel » May Tue 06, 2008 11:17 pm

Ok, it works, initially. dropping into Woz monitor I'm able to return to BASIC from memory location 0 with my 1 line program intact.

Now, I don't know much about Applesoft and where the programs are kept but is there known memory locations for storing programs? In other words, Apple 1 basic stores a few bytes from 4C-4F giving the beginning and ending locations of where the programs are stored (himem and lomem).

I'll have to check that out to see if we can store programs on a CFFA1 card and load the programs in an Apple II, or from an Apple II into the replica 1.

I just want to say to everybody like Tom, Ken, Rich, and too many others to mention; Thanks for making the replica 1 project fun, even after 5 years.

Vince

P.S. You know, the floating point error you posted about just goes to show that emulation is good but the real thing is better! You might have been chasing that ghost for a while.
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