Re: [PATCH, fortran] PR93727 Implement new EX format specifier

On 5/21/26 21:18, Jerry D wrote:
> On 5/12/26 12:14 PM, Harald Anlauf wrote:
>> Hi Jerry,
>>
>> Am 11.05.26 um 8:24 PM schrieb Jerry D:
>>> Hi all,
>>>
>>> This took me a lot longer than I wanted, but finally got it done.
>>>
>>> See the attached patch. Since my last submittal here I started over 
>>> on using the example demo Harald gave in Comment 18 of the PR using 
>>> available higher level C functions, fabs, signbit, scalbn, isnan 
>>> frexp, etc to extract the needed components. Then, using the %H 
>>> specifier to build the hexadecimal float string in 
>>> get_float_hex_string(). I added checks for zero, inf, nan, and the sign.
>>>
>>> Once I had this working for kind=8, I repeated the pattern for 
>>> kind=8, 10, and 16. I used defines around the kind=10 and 16 to avoid 
>>> where not supported.
>>>
>>> I also created defines for the C functions needed following the 
>>> examples later in the file. I dont have some of those platforms 
>>> readily available here so a web searched for those various function, 
>>> ie not tested yet. I will call it an EWAG. Engineering Wild 
>>> Assumption and Guess.
>>>
>>> I apologize for the whitespace cleanups. I had them in my worktree 
>>> from earlier attempts.
>>>
>>> I updated the two test cases added. I probably need to specify 
>>> targets on those. We can add additional testcases as deemed appropriate.
>>>
>>> Regression tested here on X86_64. Testing by others encouraged.
>>>
>>> OK for mainline. I do not plan any backport and less others think its 
>>> worth it.
>>
>> this is already in a quite good shape.  However, I have two
>> preliminary comments:
>>
>> - rounding is not yet correct.  Example:
>>
>>    real(4) :: r4
>>    r4 = 128.
>>    write(*,"(*(4x,EX0.2))") r4, abs (nearest(r4,-1.0))
>>
>> prints
>>
>>      0X8.00P+4    0XF.FFP+3
>>
>> but should print
>>
>>      0X8.00P+4    0X8.00P+4
>>
>> - real(10) and real(16) are not available everywhere.
>>    Please have a look at gfortran.dg/ieee/ieee_11.F90
>>    for one way to solve this.
>>
>> Best,
>> Harald
>>
>>> Best regards,
>>>
>>> Jerry
>>>
>>> PS I will be on travel the next 7 day however I can monitor email.
>>
> 
> I will add the checks for real(10) and real(16) to the test case.
> 
> I would like to commit this now and handle the rounding in a new PR or 
> leave this one open and identify this as patch 1 of 2.
> 
> Is this OK?

OK, then make it so.

Please adjust the commit message to indicate that this is a partial
EX implementation lacking proper rounding.

Since reading the hex format is still missing, wouldn't it be
best to stick to the existing PR?  Otherwise a new PR could
lose information that is in the old one.

Thanks for being so patient.

Harald

> Jerry
>