On 02/10/2017 11:22 AM, Janne Blomqvist wrote:
On Fri, Feb 10, 2017 at 9:14 PM, Jerry DeLisle <jvdeli...@charter.net> wrote:
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
Hmm, fascinating. What about
-mfloat128 -mcpu=power9
-mfloat128 -mabi=ieeelongdouble
-mfloat128 -mcpu=power9 -mabi=ieeelongdouble
gcc112 is a power8 machine.
$ gfc -static -mfloat128 -mcpu=power8 foo.f90
$ ./a.out
16 106 31
$ gfc -static -mfloat128 -mabi=ieeelongdouble foo.f90
gfc: warning: using IEEE extended precision long double
f951: Warning: using IEEE extended precision long double
$ ./a.out
16 113 33
$ gfc -static -mfloat128 -mcpu=power8 -mabi=ieeelongdouble foo.f90
gfc: warning: using IEEE extended precision long double
f951: Warning: using IEEE extended precision long double
$ ./a.out
16 113 33
