Re: Motion P1788/M0002.01_ProcessStructure YES
On 2009-03-22 23:17:47 -0700, Dan Zuras Intervals wrote:
> Clauses 3.4 through 3.7 define floating-point datasets &
> formats that may be used for fixed or arbitrary precision
> floating-point datatypes. And, clause 3.7 defines two
> classes of arbitrary precision datatypes: Extended, which
> are presumed to be available to either the implementation
> or the language to provide higher precisions than were
> available in 754-1985 & Extendable, which are designed
> to give the programmer direct control over the range &
> precision of both binary & decimal datatypes.
I think that these extendable precision formats are designed to be
used as fixed formats in rather small precision.
Also in traditional arbitrary precision models, the range normally
doesn't change, only the precision, whereas Section 3.7 requires
emax >= 1000 p (which may not be a good idea in high precisions,
e.g. if one wants to provide faithful rounding on functions like
sin and cos).
> However, if by "arbitrary precision" you mean a sort of
> variable precision arithmetic that takes one precision of
> operands & returns a result whose precision is a function
> of the operands then, yes, beyond conversions & FormatOf
> operations 754-2008 has no such notion.
OK.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.org/>
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Work: CR INRIA - computer arithmetic / Arenaire project (LIP, ENS-Lyon)