Re: New assembly language instructions to support OO languages?

Michael Tiomkin wrote:
> I understand that some ancient computers (in the 2nd millennium)
> used segmented memory. If we could implement this and show that it
> runs most of the programs faster, somebody would be able to build such
> a processor. Unfortunately, for "scientific" computations (PDEs,
> matrices) the flat memory model might be more efficient. From the
> other side, having a possibility to define smaller or larger segments
> can also help to matrix multiplication etc. - with larger segments
> much more memory will be preloaded on sequential access.


As I understand it, Unisys MCP machines use a version of the segmented
model that Burroughs Large Systems have used for over 40 years. Arrays
are indexed through descriptors that hold the array size and the address
of the first element. Link words on either side of the array are tagged
so that user programs can't access them. This is all part of the
overall model (no assembler, all object programs must be produced by a
trusted compiler).


I wouldn't expect this to do much for performance, but it goes a long
way to provide a more secure computer. Just think, no buffer overruns...


Louis

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