Dan Sunday’s History Part 4

Date: Sat, 31 Oct 1998 20:12:41 -0500
Subject: Re: The old Vectorbeam days...


Zonn: Glad my info was of interest to you and others.

To answer your other questions:


> #1 Do you mind if I post your letter to a "vectorgames" mailing list? It's a
> list of people pretty obsessed with video games using vector graphics. And
> as a followup would you mind if I placed a copy of your letter on the
> Cinematronics homepage?


That's fine. I have no problem with you posting this info. One thing: since
I'm sending this from my wife's email account, her name "Jassica Sunday" is
being printed as the sender. Please edit this with my name "Dan Sunday".

[No problem, I chopped off all the headers. -- Zonn]


> #2 You wouldn't have any documentation on the instruction set would you? It
> would be interesting knowing what Larry originally called the instructions.


The instruction set was very minimal, eg: there were no multiply or divide
operations. There was just a shift right with add if a set bit was shifted
out. This was used to do a multiply by repeating it the number of bits in the
word. As for the full instruction set: it was described in one of Larry's
patents, namely: US Patent # 4,053,740 (Oct 11, 1977) for a "Video Game
System". This patent explains a lot about both hardware and software, and
gives the instruction set in Larry's computer.


[Maybe minimal, but it allowed a 12x12 bit multiply in 24 cycles! Something
the 80188 couldn't do, more similar to the 80386! -- Zonn]


When I started working with Larry, we had a Z80 macro assembler with the Z80
assembly instructions removed. We then had a set of macros defining the full
instruction set plus more for Larry's machine. This let us define, for eg,
multiplication as a macro that got expanded into the correct number of basic
machine instructions. I was sure I had a listing of what all those macros
were, but haven't found it yet. I suspect it's in one of the many unpacked
boxes I have. I'll look around.


[I never heard if he found this or not. -- Zonn]


- Dan Sunday


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