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

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?

Jerry