hi Chris,

Hi Chris,

Chris Cunnington wrote:
> Since this is an off topic thread, I'd like to know something Mr. Lount
> about your assembly programming and Gemstone Warrior. I played that game in
> the 80's on an Apple here in Southern Ontario (Oakville). 

Very cool.

> I now own a
> Commodore 64 and a copy of Jim Butterfield's book on machine language. (He
> just past away in June.)
>
> I want to know if the chip you wrote assembler for was a 6502, as Apple's
> had used that chip in the Apple 2 line. 

Yes, the chip was a 6502. The one that shipped in the Apple. Later on - 
as in much later on - I installed a zip chip that took the processor 
speed up from 1mhz (yes, one megahertz) to a wopping 10mhz! Wow, ten 
times faster and Gemstone wasn't even playable!

> And whether you learned from Butterfield's book. If not, with what books and for what chip did you learn
> assembler


I don't recall which book the "Butterfield" book is. I have a whole box 
of Apple ][ books in storage. I'd have to look at them. The book was a 
green instruction set manual possibly published by MOS themselves or 
someone like Osborne (who was the O'Reily books of that era). I have a 
lot of Apple two magazines. I also worked full time selling Apple ][ 
systems for up to $14,000 a pop (with printers and VisiCalc to be sure). 
(Ah, those days are long gone though!) The game was also ported to the 
C64 and Atari 800 by my team. Those were slightly different 6502 chips 
and obviously different graphics hardware too.

In the following years I've studied many instruction sets. After a while 
they are essentially the except in the pesky details of getting it right 
with whatever processor you happen to be working on at the time. The 
biggest differences are in the number of registers, the control 
registers, the processor bit width (8, 16, 32, 64, etc...), and their 
different syntaxes. Nowadays there are many more instructions especially 
on the X86 lines. Recently I'm looking at MIPS again since I'm 
interested in the Tile64 processors.

Are you planning on working with 6502? Or other assembly langauges? What 
are you working on if I may ask?

Cheers,

peter