Re: Motion 24.03: NO
On 2011-07-10 08:37:30 -0500, Ralph Baker Kearfott wrote:
> Hossam, P-1788,
>
> My understanding of the difference between 754 and 24.03
> is the distinction between "rounding attribute" and
> "operation." The "rounding attribute" typically
> (but not always) has been implemented as a processor
> state, with associated efficiency issues when the
> rounding mode is changed. I believe (and correct me
> if I am wrong) the proposers of Motion 24.03 feel
> efficiency can be gained with an implementation
> of separate opcodes (addup, adddown, addnear, etc.) rather than
> forcing a processor mode change every time a different rounding
> direction from the previous operation is required.
[...]
But P1788 is not about hardware. Motion 24.03 could be fine for
a processor standard (that would be completely be different from
P1788).
An informational note could say that P1788 would be best implemented
on hardware that supports directed rounding (possibly except for a
direct hardware implementation of P1788), but this wouldn't even be
sufficient, as the language used for the implementation must also
support directed rounding (this is not the case of ECMAScript, for
instance).
Note that the requirements are for the users of the standard, not
for the implementer.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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