Lisp, the machine language. Was Re: Hallelujah!

From: Chuck McManis <cmcmanis_at_mcmanis.com>
Date: Sun Apr 4 12:07:42 1999

At 11:47 AM 4/4/99 -0400, Max wrote:
>So, an assembly language program for them would look like lisp, as opposed
>to MOVs, ADDs, and so forth?

Nearly, the trick is that the machine code instructions are designed with
the high level language constructs in mind. So on a LISP machine there
might be an instruction: next ptr, ptr
Which follows a LISP list construct to the next element.

> And same with Pascal?

Yes, although you could consider "P-code" to be a lower level.

> But why would anyone want something that was microcoded to run Pascal?

Speed mostly, that and ease of use with compilers.

> Are there any other languages that have gotten microcoded into a processor?

COBOL was microcoded into some of the old Burroughs machines.

Mesa was microcoded into the Xerox "D" machines.

Java was microcoded into Sun's picoJAVA chip.

It is just a question of spending precious Chip real estate only on
instructions that the "main" language needs. (the nice thing about the
Xerox D machines was that the microcode was loaded so you could change it
at will) Given todays chip budgets it makes less sense (the Sun picoJava
chip has _not_ been a success) but it is still done.

--Chuck
Received on Sun Apr 04 1999 - 12:07:42 BST