[Cfp-interest] C binding for IEEE 754-2008

[Jim Thomas]

Mike, thanks for the comments. Please see responses below - also sent to the CFP study group.

-Jim

On Aug 6, 2012, at 2:34 AM, Mike Cowlishaw wrote:

> Hi Jim,
>  
> I have read through the Part 2 draft and also Fred's comments -- it is all looking very good.  I have only a few minor comments, with perhaps the last one being the most significant:
>  
> Comments on WG14 Study Group Draft (cfp2) -- July 22, 2012
>  
> PDF page 5, para 3: this paragraph might be confusing to later
>   readers, because z/Architecture machines have had floating point
>   decimal units for around 5 years and so "This, however, provides
>   integer arithmetic only" is incorrect.  Perhaps something like
>   "Prior to the IBM System z10 processor, however, this provided
>   integer arithmetic only"?
Ok.
>  
> PDF page 10: in the table the values for Emax and Emin are different
>   from the emax and emin values in IEC 60559 -- presumably a
>   different definition is used in C11.  Worth a footnote to warn the
>   reader?  The reader is referred to IEC 60559 for semantics, but
>   using Emax instead of emax would give incorrect results.
The mismatch between the IEC 60559 and C models is indeed confusing. Yes, a footnote warning about the difference might be helpful.
>  
> PDF page 17, table: 'IEEE 754' should be 'IEC 60559'?
Right.
>  
> PDF pages 29-30: I'm not familiar with the definition of "style f
>   formatting" in C11, but it is worth emphasising that conversions to
>   strings (in printf for example) rpreserve th quantum.
Style-f formatting doesn't generally preserve the quantum exponent. The decimal a,A formatting does though.
>  
>   Perhaps add to the examples on page 30 some where c ends in 0,
>   e.g.:
>  
>     ( 1, 120, -8) 0.00000120
>     ( 1, 120, -9) 1.20e-7
Good.
>  
>   In other words, a 'default' conversion from a _Decimal to a string
>   and back to the same type of _Decimal must result in a _Decimal
>   that is identical in (s, c, q) to the original.
Assuming by 'default' you mean default a,A conversion.

> Also, it might be worth adding this link to your Wiki:  http://speleotrove.com/decimal/

Agreed

>  
> Feel free to forward this to the working group.   I'd be happy to reply to any specific questions, etc.
>  
> Cheers -- Mike
>  
>  

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