11 Nov
2001
11 Nov
'01
1:30 p.m.
At 03:02 AM 11/12/01 +0100, Iggy wrote:
Carlos Murillo skrev:
(through
Didn't the uVax II implement some of the
original VAX instructions
with emulation? I always wondered what the VUP rating would have
been were they not emulated.
in order to reduce the architecture to a single (integer) chip, only 175 of
the 304 instructions (and 6 of 14 native data types) were implemented microcode), while the rest were emulated - this subset
included 98% of
instructions in a typical program. The optional FPU implemented 70
instructions and 3 VAX data types, which was another 1.7% of VAX
instructions.
All remaining VAX instructions were only used 0.2% of
the time, and this
allowed MicroVAX designs to eventually exceed the speed of full VAX
implementations
Aha! So, if I were doing numerical linear algebra in a uVaxII w/o the optional
FPU, I could expect performance to be badly hit with respect to the 0.9 VUP
rating.
(FYI, I always tend to benchmark machines using float performance,
because that's the kind of thing that I do for a living. I look at integer
performance only as something that has an impact on sparse linear algebra
blocks, as opposed to dense system methods).
How do I know if my Vaxstation 2000 has the optional FPU? What is
its model number?
What about the Vaxstation 4000/60? Does it have a built-in FPU?
carlos.
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Carlos E. Murillo-Sanchez carlos_murillo(a)nospammers.ieee.org