advice statement

[BLARSON at ecld.#eclnet]

From:  Bob Larson <BLARSON at ecld.#eclnet>

The Prime 9950 and 9750 are examples of non-RISC pipelined architectures
that handle this problem (branch lookahead) by utilizing a special branch
cashe with an 80% success rate (according to sales literature).  Most
programmers could probably not beat this, especially since the branch
cashe is updated on the fly.  Note that a pipeline architecture can only
take the most probable path, so only one bit of the programmers guess would
be significant (which path is most probable).  The Prime 9950 and 9750,
being object code compatible with the rest of the 50 series, have no 
provision for a programmers guess of the most probable path.  Do you have
an example of a (commercially produced in quantity) machine that does
expect a guess of the most probable path?  I feel that this problem is
best solved in the machines that need it by additional hardware rather
that expecting all programs to be updated to run on it.

Bob Larson <Blarson at Usc-Ecl.Arpa>
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