[Cfp-interest 2727] WG14 IEEE 754-C binding meeting minutes 2023/02/28

[Jim Thomas]

Corrections and additions welcome.

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CFP meeting 2023/02/28

Damian McGuckin,
David Hough,
Fred Tydeman,
Hans Boehm,
Ian McIntosh,
Jim Thomas,
Mike Cowlishaw,
Paul Zimmermann,
Rajan Bhakta,
Vivian Van Loan

March 29, 8 AM PDT / 11 PM EDT / 3 PM UTC - next meeting

Floating point rounding modes - lots of email discussion.
Hans presented slides (will be emailed to reflector after meeting).
 fenv rounding issues.
 interacts with constexpr.
 FENV_ACCESS not supported in C++
 Uses:
  interval arithmetic
  run same code with different rounding modes to assess the effect of round-off errors
 Problems
  no constant folding
  effect on library functions
  rounding of signed constants
  global FP state
 Solutions
  deprecate fesetround()
  add static rounding to C++
  correctly rounded math functions with extra argument
   (to indicate rounding direction)
  correctly rounded FP types
David Hough:  Dynamic rounding and compilers are a bad mix.
 Static rounding modes are much better.
 Likes dynamic exception modes (for debugging)

WG14 meeting results:  all CFP suggestions accepted.

Carry-over Action Items:
 David Hough not done yet.

Action Items from last meeting 
 All completed
  N3105 accept by WG14
  Jim to submit [Cfp-interest 2684] as a CD2 comment.
  Jim to submit [Cfp-interest 2686] as a CD2 comment.

"floating types" and float_t, double_t.
 Jim to submit CD2 comment to italicize “real floating types” in 6.2.5#14.
 Re definition of float_t, double_t
  Fred:  Microsoft eval method is not any of float, double, long double,
          so, what should float_t be?
  No resolution yet for CD2 comment
  To be continued in email discussion
 "width" issue
  No resolution yet for CD2 comment
  To be continued in email discussion

TS Part 4 -- minor formatting updates.

TS Part 5 -- redone as four separate features.
  It still has a few issues to be resolved.


Fred Tydeman
Jim Thomas
Rajan Bhakta