NEC SX4 supports three hardware floating-point formats

[uunet!cwi.nl!Dik.Winter]

 > All models support IEEE, 
 > Cray Research Inc and IBM Corp floating point data formats fully 
 > implemented in the hardware, NEC says. 
 >  ...

That is upward compatibility for you.  The SX-3 supported two formats
(IBM and Cray) and the SX-2 supported one format.  Extrapolation says
that the SX-1 supported no format; but it appears that is not true.

 > After all that effort, I would think adding VAX support as well would not
 > have been much more trouble!

Wait for the SX-5!

 >                                I wonder if subnormal numbers are supported
 > in hardware, if division is correctly rounded, and if IBM extended and
 > VAX H format are in hardware?

I do not know how the IEEE format will behave, nor do I know whether
division will be correctly rounded (and does it support all Cray
anomalities with respect to division?).  I do know that NEC Quad is
not the same as IBM Quad, IBM Quad has 120 bit mantissa, NEC Quad has
only 112 (two Doubles with a shifted exponent in the second).  Also
NEC Extenden Exponent (Cray format) is not identical to Cray; the
exponent range is larger.  At least that was the case for the SX-3.

dik
--
dik t. winter, cwi, kruislaan 413, 1098 sj  amsterdam, nederland, +31205924098
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