[Cfp-interest 2726] Re: definition of "floating types"

[Jim Thomas]

> On Mar 3, 2023, at 8:17 AM, Vincent Lefevre <vincent at vinc17.net> wrote:
> 
> On 2023-03-02 10:11:00 -0800, Jim Thomas wrote:
>> Evaluation methods don’t affect function calls, including library
>> functions. (TS 18661-5 provides a way of having them do so.) So,
>> fma() must produce a double format result, with any evaluation
>> method.
> 
> The issue is that 5.2.4.2.2p19 says
> 
>  2  evaluate all operations and constants to the range and precision
>     of the long double type.
> 
> and various function calls are also operations.

The same paragraph begins with:

The values of floating type yielded by operators subject to the usual arithmetic conversions, including
the values yielded by the implicit conversion of operands, and the values of floating constants are
evaluated to a format whose range and precision may be greater than required by the type. Such a
format is called an evaluation format. In all cases, assignment and cast operators yield values in the
format of the type. The extent to which evaluation formats are used is characterized by the value of
FLT_EVAL_METHOD:

This is intended to give the universe of operations to which “all operations” refers.

- JIm Thomas


> See for instance the
> table in 5.2.4.2.3p10. So instead of "all operations", it should say
> which operations are concerned.
> 
> -- 
> Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
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