Lisp, the machine language. Was Re: Hallelujah!

From: Derek Peschel <dpeschel_at_u.washington.edu>
Date: Sun Apr 4 03:05:38 1999

> >Actually, I thought they had microcode or assmebly language. Therefore,
> >they have a compiler to create the microcode or assembly language. It may
> >not be well-documented (or advertised) but it's there.

> This is a mistaken impression. Actually, microcode is not compiled. For
> any computer which is microprogrammed, there is a sequence of
> microinstructions which implements each executable statement of the
> computer. In the case of the Lisp machine (such as those built by
> Symbolics - like the 3600), the machine instructions are, in fact, the
> operators of Lisp. So, there is within the microcode of a List machine
> a sequence of microinstructions which implements directly the function
> of a Lisp operator, such as CAR.

I was unclear.

I meant that the microcode/assembly language words _corresponding to a
particular LISP program_ were created from that program and then executed.
If you define a function (like the ever-popular factorial function)
something has to be stored in memory as the definition; presumably it is
some sort of primitive (as in not-easily-decomposed) machine language, and
presumably there is a program that converts source text into object code.

So wouldn't that converter be a compiler? I believe that a number of subtle
details happen during the conversion process, so you couldn't even say the
compiler is a simple compiler.

-- Derek
Received on Sun Apr 04 1999 - 03:05:38 BST