Pick assembly, was Re: XT 5160

[Jay West]

Cameron wrote...
> I've always wanted to see what Pick assembly looked like. Is there a 
> reference
> anywhere?

I could pull up some of my old code for you if you want. Pick Assembler is 
quite difficult. Not because of the instruction set (although the 
instruction set is only 1/2 the issue), but because there was no protection 
among modes, and all the conventions were completely undocumented.

You could read the assembler manual cover to cover and understand it 
thoroughly, and still only write code that was pretty much guaranteed to 
crash the machine every run.

In addition, the instruction set was created before the hardware was even 
selected. As a result, the instruction set is very highly tied in to the 
data formats on disk. So unless you understand the internal formats and 
structures used for data storage, again - the assembler would seem 
meaningless - or, well, odd at the least.

That all being said though, it was the most enjoyable instruction set I ever 
worked with. Since it was so thoroughly undocumented, even in the released 
manuals, there weren't a ton of people that knew it well. That's why folks 
like me worked on contract for several of the Pick licensees developing the 
OS. Too hard to find and hire enough people in-house that knew it. But once 
the lightbulb goes off in your head when you get the whole picture, it's an 
incredibly neat environment.

Jay West