Re: is Vax adressing sane today

anton@mips.complang.tuwien.ac.at (Anton Ertl) writes:

mitchalsup@aol.com (MitchAlsup1) writes:

In my opinion, DEC was caught at an ugly time for them. They did not
have the transistor budget for a GBOoO implementation at exactly the
time they also needed a clean transition to 64-bits (even more trans-
istors). DEC did have the transistors for a medium OoO implementation
but unlikely the 64-bit transition.

>
For the K8 the switch from 32-bit to 64-bit was reported to have cost
5%.  You were there.  Are the reports wrong?

In addition, VAX is a 32-bit architecture.  It was not necessary to
extend it to 64 bits and do OoO at the same time.  IBM stuck with its
31-bit addresses in s390 until 2000 when it was extended to the 64-bit
z/Architecture (and the first implementation, the z900 was scalar, not
even in-order superscalar; they got superscalar in the z990 in 2003
and apparently out-of-order with the z196 in 2011; but then, IBM's
customers are probably less performance-sensitive than DEC's customers
used to be).  Intel only delivered Merced (IA-64) in 2002 and
delivered Nocona (AMD64) in 2004.

Sure, there was marketing pressure to deliver 64-bit architectures
early, but I think that a competetive 32-bit OoO VAX in 1996 with an
announcement of a future 64-bit extension would have been fine
wrt. marketing.  And a 0.25um 64-bit VAX in 1999 or 2000 (they shrank
the 21264 to 0.25um in 1999) would have certainly made good on that
promise.

- anton
--
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>