Re: Will the real Altair Basic please stand up?


"Mr. Emmanuel Roche, France" <roche182@xxxxxxxxxxx> wrote in message
news:486a8259$0$931$ba4acef3@xxxxxxxxxxxxxxxxx
Hello, John!

I was surprised by your endeavour. You may remember that I have
disassembled
a few programming languages running under CP/M. My main tools are MAC and
SID. The only difference is that the MITS Altair BASIC versions that I
have
disassembled load at 0000H (not Good Old 0100H). That's why I wrote (and
published in the comp.os.cpm Newsgroup) a HEXBIN utility, enabling me to
create those BIN files under CP/M (it is the comp.os.cpm Newsgroup,
remember?).

There were dozens of versions of MITS Altair BASIC, including "Extended
Version", "Disk Version" (which later became "CP/M BASIC" Version 4.41
before becoming our MBASIC Version 5.21), and one which could interest
you:
"RST-less Version". That is to say: to shorten the code, the most often
used
subroutines were coded as Intel 8080 RST interrupts. Of course, it was a
bad
idea that Gary Kildall did not made. After a while, they recognized this,
and set apart one RST for users, then made a "RST-less Version" (before
the
"Disk Version" and "CP/M Version") for people needing more than one
interrupt.


All excellent suggestions, thank you. But I want this system to be a
"historical snapshot" of sorts, running 4K ram with 4K Basic. Once it's all
checked out as good, I'm mothballing it and a few spare S-100 cards for the
grandkids. I know it's buggy, that that's the was it was (is).

For my real work, I have an IMSAI system running ZCPR 3 with dual 8" drives
and a 20Mb hard disk loaded with CP/M goodies. In case anyone is wondering
that hard drive weighs in at 90lbs! I had to reinforce the table. I also
have an Altair 8800B running MS Basic (the actual ROM version, on a MITS ROM
card). So, I do know that Billy, at some point, got around to making it
ROMable.


Now that I have the serial card running on the Altair, I've addded a
Cromemco 8K Bytesaver EPROM card. I burned the control SW for the
Bytesaver
card onto a 2708 and added a little binary loader in the space that was
left. My goal is to put Altair BASIC (4K ver 3.2) onto some of the
remaining EPROM chips.

I understand that you have one Altair? In this case, would you mind
commenting (in English: the problem is that I am French and not an
electronician, so have no idea how to comment it in English) my
disassembly
of the initialization routine for the MITS 8800? Then, you could change it
to suit your own system. (I have still another question regarding one
mysterious I/O port of the MITS 8800.)

Sure, I'll give you my comments, just post the code. But what is the code
supposed to initialize? If you're talking about ports, is it a UART init
routine?

Is the MBL more than just a simple Binary Loader? Does it load the
binary
in a non-sequential fashion, moving it around? And the big question:
Does
anyone have a "straight" binary of 4K Basic, or a copy of MBL?

Well, I got all the versions that I disassembled from the Web site of
Peter
Schorn, and I can confirm that they correspond to the 80% disassembly
available on the Web. (Altair 4K BASIC and Altair 8K BASIC were generated
from one single file with conditionals.)

From what I have read (all those old MITS manuals), the 2 most popular
versions were paper tape version (for the ASR-33 Teletype) and a cassette
tape version (for the ACR). All the versions that I have disassembled had
CLOAD and CSAVE commands (but, now that I have the source code, I could
produce a version without them, if you would not mind getting it as an
Intel
HEX file).


Hex file would be great, thanks. Got lotsa' loaders laying around :)

If you have any question...

Yours Sincerely,
Mr. Emmanuel Roche, France





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