30 Dec
2017
30 Dec
'17
8:20 a.m.
On 12/29/17, Kevin Bowling <kevin.bowling(a)kev009.com> wrote:
Enlightening to read
about how the coherence protocol was developed in software. How was
the ISA, and I assume even implementation detail, kept equal or close
enough to the eventual microprocessor parts? Does the "Privileged
Architecture Library" mean it was effectively microcoded?
Yes, IMO the Alpha PALcode was a form of microcode. DEC designed the
Alpha ISA with the hardware folks working closely with the VMS and DEC
UNIX (soon to become Tru64 UNIX) OS groups to insure that the correct
balance of PALcode vs. implemented-in-hardware was struck.
-Paul W.