[Beowulf] Stroustrup regarding multicore

Robert G. Brown rgb at phy.duke.edu
Tue Aug 26 20:19:06 EDT 2008


On Tue, 26 Aug 2008, Perry E. Metzger wrote:

> There are a load of weird things out there that don't look like
> this. Have a gander at Palm's operating system for their handhelds
> sometime -- or the original Mac OS.

If/when I can get such a gander and have time to take it, I will...;-)

I don't know how much of current compiler design was bent by Intel's
original segmented memory model.  They had code data stack and extra (or
something like that -- but I recall EX,SX,DX, and CX).  But then
motorola's memory model was flat instead of segmented, and it wasn't
until the 386 or 486 or thereabouts before one "could" run an x86 flat
and there was too much legacy code about at that point and it never
really happened.

But way, way long ago -- on IBM mainframes and with cards -- my original
and only "real computer science course" was on computer architecture and
microprogramming and so on, and IIRC even then the subroutine call
ritual was push arguments onto the stack, allocate locals by moving the
stack pointer, then dereference both by relative displacement from the
stack pointer.  C calls by reference in part because a function return
simply restores the pointer (de facto losing the locals) and then pops
the stack (de facto losing the arguments, although one "can" get them
if one is working in assembler and can prevent stack movement in
the meantime.

    rgb

>
> Perry
>

-- 
Robert G. Brown                            Phone(cell): 1-919-280-8443
Duke University Physics Dept, Box 90305
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