[Cfp-interest 1454] WG14 IEEE 754-C binding meeting minutes 2020/01/09

Rajan Bhakta rbhakta at us.ibm.com
Thu Jan 9 09:38:55 PST 2020


  Attendees: Rajan, Jim, Mike, Ian, David H.

  New agenda items:
    None.

  Carry over action items:
    CFP: Put the tgmath redefinition as a proposal to the standard once we 
have a base document with TS Part 3 in it.
 
  Last meeting action items:
    Fred: Update erange proposal based on CFP 1437 and CFP teleconference 
discussion. - Unknown.
    Jim: Submit http://wiki.edg.com/pub/CFP/WebHome/C2x_proposal_- 
_NaN_and_infinity_macros_-_20191108.pdf to WG14. - Done.
    Rajan: Compile example code in 
http://wiki.edg.com/pub/CFP/WebHome/C2x_proposal_- 
_why_no_wide_string_strfrom_functions_v2.pdf. - Done.
    Jim: Choose how to attach footnote in 
http://wiki.edg.com/pub/CFP/WebHome/C2x_proposal_- 
_why_no_wide_string_strfrom_functions_v2.pdf; mention the other approach 
in the problem description. - Done.
    Jim: Draft a paper proposing changing the “cr” prefix for correctly 
rounded functions to “cr_”. Include with other suggested changes in 
response to Jens’s naming paper. - Done.
    David H: Draft words to recommend honoring properties (Ex. even/odd, 
periodicity) of math functions that would follow automatically from 
correct rounding. - Not done.
      Jim: Find a place for words about math function properties. 
Coordinate with David H (previous AI). - Not done.
        Comments:
          Ian: Monoticity as well and making correctly rounded be 
recommended practice.
          David: We can say if it is correctly rounded, they get the 
properties anyways.
    Jim: Draft a proposal to change the return words for powr and add the 
footnote (presented in the meeting) to justify powr. - Done.

  New action items:
    Jim: Look at seeing what would be involved in removing Annex J types 
that already have the same basic types.
    Jim: Get a WG14 document number and submit 
C2x_proposal_-_why_no_wide_string_strfrom_functions- 20191230.pdf.
    Jim: Get a WG14 document number and submit 
C2x_proposal_-_names_and_locations-20200105.pdf.
    Jim: Ensure natural log is written as log in the standard (regarding 
C2x_proposal_-_powr_justification_wording-20200104.pdf). 
    Jim: Ensure thin spaces are put where needed in 
C2x_proposal_-_powr_justification_wording-20200104.pdf. Ex. Between the e 
and y in the "e^y log x" in three places. 
    Jim: Update links on the C FP wiki to point to the latest drafts of 
the TS parts and look into having a section for working drafts.
    Rajan: Ensure casting to _Float16 won't cause a problem with the using 
INFINITY wherever a constant expression can be used change we proposed.

  Next Meeting(s):
    Wednesday, February 19th, 2020, 11:00 EST, 8:00 PST, 4PM UTC
    Same teleconference number.
    Please notify the group if this time slot does not work.
      Jim away Jan. 14-28th.

  Discussion:
    754 revision:
      Done!
      CFP 1443 has the paper/article David wrote.
      Drop this agenda item.

    C++ Liaison:
      Nothing.

    C2X integration (
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2433.pdf):
      Draft with TS 1, 2, and 4a (Latest C2X draft: 
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2454.pdf, also as link on 
CFP wiki)
      Part 3 - Was in a branch as work in progress prior to Jens stepping 
down as editor. As Annex J.
      Part 4b - Looking as an updated TS.
      Part 5a,b,c,d
 
      C2X target: 2023
      Jim: Idea is to propose IEEE 2019 binding in the next C meeting. We 
can discuss next CFP meeting.

      Jim: Question: Should we remove value redundant types from Annex J? 
Ex. _Float32 being the same as float, _Float64 being the same as double, 
_Float32x being the same as double or long double. We added this as 
consistency, but the initial goal was just to provide nomenclature for the 
types.
        *AI*: Jim: Look at seeing what would be involved in removing Annex 
J types that already have the same basic types.

  Action item details:
    Fred: Update erange proposal based on CFP 1437 and CFP teleconference 
discussion.

 
    Jim: Submit http://wiki.edg.com/pub/CFP/WebHome/C2x_proposal_- 
_NaN_and_infinity_macros_-_20191108.pdf to WG14. (
http://wiki.edg.com/pub/CFP/WebHome/n2469.pdf)
      Looks good.

    Rajan: Compile example code in 
http://wiki.edg.com/pub/CFP/WebHome/C2x_proposal_- 
_why_no_wide_string_strfrom_functions_v2.pdf. (See Rajan’s CFP 1441)
      Looks good.
 
    Jim: Choose how to attach footnote in 
http://wiki.edg.com/pub/CFP/WebHome/C2x_proposal_- 
_why_no_wide_string_strfrom_functions_v2.pdf; mention the other approach 
in the problem description. 
http://wiki.edg.com/pub/CFP/WebHome/C2x_proposal_-_why_no_wide_string_strfrom_functions- 
20191230.pdf
      Looks good.
      *AI*: Jim: Get a WG14 document number and submit 
C2x_proposal_-_why_no_wide_string_strfrom_functions- 20191230.pdf.
 
    Jim: Draft a paper proposing changing the “cr” prefix for correctly 
rounded functions to “cr_”. Include with other suggested changes in 
response to Jens’s naming paper. 
http://wiki.edg.com/pub/CFP/WebHome/C2x_proposal_-_names_and_locations-20200105.pdf
      cr_ was never proposed by any paper.
      Moving the SNAN macros does follow the suggestion of renaming, but 
also moves it which was not previously proposed.
      *AI*: Jim: Get a WG14 document number and submit 
C2x_proposal_-_names_and_locations-20200105.pdf.
 
    David H: Draft words to recommend honoring properties of math 
functions that would follow automatically from correct rounding.
      Still to do.
 
    Jim: Find a place for words about math function properties. Coordinate 
with David H (previous AI).
      Suggest adding a title to the table in F.3#23.
        David: Functions that IEC 60559 recommends be correctly rounded
        David: The first table title should also be changed to distinguish 
this table. Ex. Binding of operations required by IEC 60559; Binding of 
functions or operations recommended by IEC 60559.
        Jim: Or "Bindings of operations required by IEC 60559"; "Bindings 
of operations recommended by IEC 60559" See C FP 1453
      Suggest adding a second recommended practice to F.10.
 
    Jim: Draft a proposal to change the return words for powr and add the 
footnote (presented in the meeting) to justify powr. 
http://wiki.edg.com/pub/CFP/WebHome/C2x_proposal_-_powr_justification_wording-20200104.pdf
      *AI*: Jim: Ensure natural log is written as log in the standard 
(regarding C2x_proposal_-_powr_justification_wording-20200104.pdf). 
      *AI*: Jim: Ensure thin spaces are put where needed in 
C2x_proposal_-_powr_justification_wording-20200104.pdf. Ex. Between the e 
and y in the "e^y log x" in three places. 

  Other issues:
    WG14 editor change
      Jim and Rajan meeting with David Keaton regarding finishing off the 
work.

    Is “Floating-point extensions for C” still an appropriate description 
of CFP work? See Mike’s email CFP 1445.
      Jim: "IEC 60559 Floating point support in C"?
      Sounds good.
      Jim: Also remove reference to 2008 on the website.
      Jim: Update links to the published TS's on the website.
        Rajan: Link published for all, and have working drafts for any 
ones with changes or that are not in C2X.
      *AI*: Jim: Update links on the C FP wiki to point to the latest 
drafts of the TS parts and look into having a section for working drafts.

    Issue for _Float16: INFINITY has type float so widens operations with 
_Float16 operands.
      Jim: Ideally NAN and INFINITY macros would be _Float16 if it was 
supported. We could add a comment suggesting putting a cast to _Float16 in 
front of INFINITY if you really wanted operations to stay in _Float16 
type.
        Ian: Doesn't work for SNAN's.
        Jim: Not an issue since we have type'd versions of those.
        May be an issue for constant expressions.
        *AI*: Rajan: Ensure casting to _Float16 won't cause a problem with 
the using INFINITY wherever a constant expression can be used change we 
proposed.


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