Re: PCODE Interpereters 101

aduncan (aduncan@cs.ucsb.edu) wrote:
: Scott Amspoker wrote:
: > I always felt that P-code's static links weren't a very efficient


: I recall reading (citations, anyone?) that the vast majority of
: variable references in real programs are either local or global;


I vaguely recall seeing something of this nature quoted as the reasons
why the B5000 series did not have a display. OTOH, the B6000 series
did :-) The difference may have been due to the nature of the programs
examined.


: aduncan@cs.ucsb.edu
: [I would guess that there are some programs whose performance depends
: greatly on the speed of up-level references, but not many. -John]


My personal guess would be that (IIRC) the B6000 ran entire "programs"
within a "context" that was somewhat equivalent to "calling from
within the OS). This could mean that the equivalents of "system calls"
looked more like "library calls", and also that what a programmer
thought of as "global data" was actually the "block data" of a block a
few levels down in the "call tree" of the system. Anybody with a
better memory want to clarify? (or is there not enough grease left
where once was a horse? :-) Of course, one could counter with a
"semi-display" that "bookmarked" the outermost frame, or what the
programmer "thought" was global...


Mike
| albaugh@agames.com, speaking only for myself

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