🚀 go-pugleaf

On 2018-08-14 03:38, Charlie Gibbs wrote:
> The other machine that stands out in my mind is the PDP-11.  I once
> hand-disassembled the Dungeon machine code and was stunned by its
> elegance.  Making R7 the program counter and R6 the stack pointer,
> plus predecrement and postincrement, made it possible to do all sorts
> of nifty program control stuff with what at first looked like ordinary
> data manipulation instructions.  The Dungeon binary was threaded code
> implemented in hardware.

You do know that Dungeon is written in FORTRAN? So you were 
disassembling something produced by a compiler.

That said, as a reflection on all other comments on PDP-11 and other 
machines around, I also happen to think that the basic PDP-11 
instruction set is extremely nice. And yes, having the PC and SP just 
being general registers do add to the elegance. (The VAX lost a bit of 
that, since even though the PC was a general register, there are some 
restrictions surrounding it, compared to other general registers.)

Yes, the PDP-10 is also a very nice machine, with some parts very 
beautifully done.
The PDP-10 and PDP-11 are designed very differently in some ways, but 
they are both very orthogonal. However, the PDP-11 is also very 
symmetric, which the PDP-10 isn't. So depending on what tickles you the 
most, I can certainly see either the PDP-10 or PDP-11 coming out on top.
The VAX, for all it's niftyness just went a little too far and lost some 
of the elegance of the PDP-11.

And I'm not at all surprised that Rich Alderson would place the PDP-10 
first.

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: b...@softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol