6 Aug
2008
6 Aug
'08
9:13 a.m.
>>>> "John" == John Foust
<jfoust at threedee.com> writes:
John> At 09:08 AM 8/6/2008, Paul Koning wrote:
> Another earlier example is BASIC-PLUS for the
PDP-11. That's an
> incremental compiler to P-code. Also, in the earlier versions
> (RSTS-11, for the no-MMU PDP-11s) it included multitasking
> (timesharing) support in the P-code machinery. The later versions
> (RSTS/E) didn't need that because there was a real kernel with MMU
> hardware.
John> P-code to a virtual machine, or just tokenized to save parsing
John> time?
P-code. It was called "push-pop code" because it would execute on a
stack machine (like a B5500). And it had some rather interesting high
level operations. Not just floating point (which was something not in
the 11/20 instruction set) but also primitives to operate on matrices
(like "invert this matrix) as a primitive opcode).
John> I thought it was just tokenized because there were
John> "de-compilers" that restored "compiled" code to real
source.
You may be thinking of RT-11 BASIC, where the "list" command actually
did exactly that.
paul