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Re: convertFormat and signaling NaN

Date: Mon, 14 Mar 2011 11:30:37 +0100
From: Vincent Lefevre <vincent@xxxxxxxxxx>
To: stds-754@xxxxxxxx
Subject: Re: convertFormat and signaling NaN

On 2011-03-13 17:24:57 -0700, Dan Zuras IEEE wrote:
    While it is true that convertFormat doesn't preclude
    formatOf being the same format as source, it is also
    true that it does not include it.

What do you mean by "does not include it"?

The IEEE 754 standard says: "Implementations shall provide the
following formatOf conversion operations from all supported
floating-point formats to all supported floating-point formats,
as well as [...]".

So, if some format, e.g. binary64, is supported, then
binary64 convertFormat(binary64) shall be provided.


Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>

        This is the sense in which I meant it was an
        oversight.  I think it would be better said
        as from all supported formats to all OTHER
        supported formats.  There are examples in
        clause 3 that also miss this point.

        As I said, while I personally believe it would
        be better to interpret a null conversion as a
        copy, I would be OK with a language that
        considers it a conversion instead.

        It is your call.


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