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From: rchrd@well.UUCP (Richard Friedman)
Newsgroups: comp.arch,comp.lang.fortran,comp.misc
Subject: Re: Quadruple-Precision Floating Point ?
Keywords: REAL*16 hardware
Message-ID: <10100@well.UUCP>
Date: 23 Dec 88 18:32:53 GMT
References: <8561@alice.UUCP> <3688@s.cc.purdue.edu> <285@loligo.fsu.edu>
Reply-To: rchrd@well.UUCP (Richard Friedman)
Organization: Pacific-Sierra Research,  Berkeley CA 94705
Lines: 24

The NEC SX-2 supports 128 bit quad precision in hardware.
The floating point format is IBM, tho, so the resulting
values are about 33 significant ecimal digits in the
dynamic range 10**-79 to 10**75.

THey also support complex double precision and
complex quad precision (256 bits). But I am not sure
how much of this is in hardware or software.

I should also mention that on average, the Cray systems
are significantly slower trying to do double precision
in software, than straight single precision.  One of the
first optimization techniques we teach in our seminars
is to remove all use of double precision (except where
absolutely needed in critical calculations)..  Luckily
Cray compilers have a compile time option that causes
the compiler to ignore all double precision declarations!
So, in many cases, with one change onthe call to the compiler
we can speed up programs sometimes by a factor of 10 or
more !!
-- 
 ...Richard Friedman [rchrd]  Berkeley, CA.                         
    rchrd@well.uucp        -or-
   {ucbvax,lll-lcc,pacbell,hplabs}!well!rchrd