On 07.01.22 10:22, Jakub Jelinek wrote:
On Thu, Jan 06, 2022 at 09:01:54PM +0100, Thomas Koenig wrote:
On 06.01.22 06:00, Michael Meissner via Fortran wrote:
What is still missing is the conversion for unformatted I/O, both
ways. I'll start doing some stuff on it. Just one question:
What are functions that I can use to convert from IBM long double
to IEEE and long double and vice versa? It was in an e-mail somewhere,
but I cannot find it at the moment.
So, what's the plan for that?
Can't find CONVERT= in Fortran 2018, so I assume it is a non-standard
extension,
Correct.
https://www.intel.com/content/www/us/en/develop/documentation/fortran-compiler-oneapi-dev-guide-and-reference/top/language-reference/file-operation-i-o-statements/open-statement-specifiers/open-convert-specifier.html#open-convert-specifier
documents the Intel one
We followed Intel on that one. NAG also has it
(although the details differ).
and we accept
CONVERT='native'
CONVERT='swap'
CONVERT='big_endian'
CONVERT='little_endian'
Now, I suppose for powerpc64le we want to add
some more, but the question is how they play together
with the byteswapping and how to name them, so that
it is clear they talk about REAL/COMPLEX KIND=16 format
and nothing else. Can we (or do we) want to allow
multiple comma separated strings from the orthogonal
choices, like
CONVERT='big_endian,ibm_extended'
CONVERT='swap,ieee_extended'
or add ibm_extended, ieee_extended and strings that
combine those with swap, big_endian and little_endian
ibm_extended_swap, ieee_extended_little etc.?
In
https://gcc.gnu.org/pipermail/fortran/2021-October/056895.html
I made a suggestion how how the format could look like. I used
a plus sign instead of a comma because I thought the environment
variable should follow the same syntax as the CONVERT specifier,
and I did not want to think about having commas in there :-)
Thinking about this again after some time, I think the syntax of
the environment variable would be clearer if the keywords for
the two conversions were separate, so somethig like
big_endian;r16_ieee;r16_ibm:10-20;
for the environment variable and
CONVERT="big_endian,r16_ibm"
would probably be better.
Best regards
Thomas
