On 02/09/2017 08:05 PM, Steve Kargl wrote:
On Thu, Feb 09, 2017 at 07:35:11PM -0800, Jerry DeLisle wrote:
On 02/09/2017 12:40 PM, Janne Blomqvist wrote:
On Thu, Feb 9, 2017 at 8:33 PM, Steve Kargl
<s...@troutmask.apl.washington.edu> wrote:
On Thu, Feb 09, 2017 at 12:10:02PM +0200, Janne Blomqvist wrote:

That being said, I think even with Steve's patch, it's not guaranteed
to give you IEEE 754-2008 binary128. E.g. on IBM POWER targets,
depending on the ABI you may get an IBM extended double (double-double
or __ibm128) format. Although if IEEE binary128 is also available,
with Steve's patch you should get that one has it has more precision
that __ibm128.

I do not have to a IBM POWER system, so cannot easily check the
effect of my patch.

On IBM Power

program foo
    use iso_fortran_env
    REAL(REAL128) x
    print '(3(I0,1X))', kind(x), digits(x), precision(x)
end program foo

$ gfc -static foo.f90
$ ./a.out
16 106 31


That is the double-double format.  The gcc manual says that
powerpc takes a -mfloat128 option (among others).  This will
probably give you 16 113 33.


$ gfc -static -mfloat128 foo.f90
$ ./a.out
16 106 31




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