4 Apr
2025
4 Apr
'25
8 p.m.
Bob Grabau <rgrabau1(a)verizon.net> write:
As my memory serves, there was a class given by the
Southern
California Computer Society (SCCS) in which the disassembled the
Altair Basic (not sure if it was the 4k or 8k version) and used the
output of that disassembly for the class. There was a guy who had the
complete annotated (by the class) of the source as printed out copies
in his trunk, which he just handed out to anyone that asked for it.
This was somewhere between 1975-1978 (76-77 most likely) when I was a
member of SCCS.
I was part of that disassembly effort and remember it well! I'm pretty
sure I still have my copy of it stashed away here. It was a lot of
fun. I had been a very early (1974) user of the 8080 at NCR, and
this gave me a chance to contribute to the knowledge base.
One thing I intend to do with this listing is find a piece of code
I worked to disassemble, and read the comments.
As I recall, it was part of some error handling. It consisted of a
string of three-byte instructions that did nothing important, but if you
jumped into the second byte of one, it would (as I recall) act as a
two-byte instruction and load a register with an error code. After
executing that 2/3 instruction, it fell into the remaining string of
three-byte instructions which did nothing of interest. At the end,
it would take the value that had been loaded earlier and use it.
I was simultaneously impressed and appalled by this space-saving
coding technique.
I'm disappointed that two printer pages are combined into a single
PDF page, as it makes it a bit difficult to read. Still, it is a
great window into the minds of Bill, Paul, and Monte.
Alan Frisbie
4 Apr
4 Apr
9:15 p.m.
New subject: Altair BASIC Source Code released
On 4/4/2025 2:00 PM, Alan Frisbie via cctalk wrote:
Bob Grabau <rgrabau1(a)verizon.net> write:
It was quite common back in the day. :-)
As my memory serves, there was a class given by
the Southern
California Computer Society (SCCS) in which the disassembled the
Altair Basic (not sure if it was the 4k or 8k version) and used the
output of that disassembly for the class. There was a guy who had the
complete annotated (by the class) of the source as printed out copies
in his trunk, which he just handed out to anyone that asked for it.
This was somewhere between 1975-1978 (76-77 most likely) when I was a
member of SCCS.
I was part of that disassembly effort and remember it well! I'm pretty
sure I still have my copy of it stashed away here. It was a lot of
fun. I had been a very early (1974) user of the 8080 at NCR, and
this gave me a chance to contribute to the knowledge base.
One thing I intend to do with this listing is find a piece of code
I worked to disassemble, and read the comments.
As I recall, it was part of some error handling. It consisted of a
string of three-byte instructions that did nothing important, but if you
jumped into the second byte of one, it would (as I recall) act as a
two-byte instruction and load a register with an error code. After
executing that 2/3 instruction, it fell into the remaining string of
three-byte instructions which did nothing of interest. At the end,
it would take the value that had been loaded earlier and use it.
I was simultaneously impressed and appalled by this space-saving
coding technique.
I'm disappointed that two printer pages are combined into a single
PDF page, as it makes it a bit difficult to read. Still, it is a
great window into the minds of Bill, Paul, and Monte.
They sold a book containing a complete, commented dis-assembly of BASIC
on the TRS-80 Model 3. I still have my copy of the original book and
a Xerox of it my father did for some reason.
bill
13
days inactive
13
days old
1 comments
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participants (2)
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Alan Frisbie -
Bill Gunshannon