[Cfp-interest 1752] Re: Underflow range error

[Jim Thomas]

Range errors are only for library functions. 

With abrupt underflow tiny results are not exact.

- Jim Thomas

> On Aug 16, 2020, at 11:46 AM, Fred J. Tydeman <tydeman at tybor.com> wrote:
> 
> On Fri, 14 Aug 2020 11:10:18 -0700 Jim Thomas wrote:
>> 
>> Or, we might explicitly regard exact underflow to be a range error condition. For example, add after the first sentence in #6
>> 
>>  Then a range error occurs, even if the value can be exactly represented in the specified type. ...
> 
> It seems strange to me the fdim(x,y) would be an underflow range error
> when x-y as a subtract operation with the same operands is not.
> Both are exact subnormal results.  And fdim() is defined as x-y.
> 
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> Fred J. Tydeman        Tydeman Consulting
> tydeman at tybor.com      Testing, numerics, programming
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