4 Apr
1999
4 Apr
'99
12:07 p.m.
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