[Cfp-interest] WG14 IEEE 754-C binding meeting minutes 2018/01/09

[Fred J. Tydeman]

On Tue, 9 Jan 2018 13:04:35 -0600 Rajan Bhakta wrote:
>
>    Fred: Look through the new functions and see what is missing in Annex 
>F. - Not done.

18661 versus 754

18661 has
  remainder(x, +/-inf) returns x for x not infinite. [Allows x=NaN]
754 has
  remainder(x, inf) is x for finite x. (5.3.1)
  remainder(x, inf) is exact for finite normal x. (6.1)
  remainder(subnormal, inf) signals underflow. (6.1)

18661 has
  remainder(+/-0, y) returns +/-0 for y not zero. [Allows y=NaN]
754 has
  r = remainder(x, y) is defined for finite x and y ... (5.3.1)
  If r = 0, its sign shall be that of x. (5.3.1)

18661 has
  roundeven() "(that is, to the nearest value whose least significant
  bit 0)."  It should be "least significant integer bit".
754 has
  no such phrase in (5.3.1, 5.9)

Not sure about min, max, minmag, maxmag, since I am looking at 18661-1
(2014) and there have been updates to it.

18661 has
  nextup(-HUGE_VAL) is not mentioned.
754 has
  nextup(-inf) if the finite negative number largest in magnitude. (5.3.1)

18661 has
  nextdown(+HUGE_VAL) is not mentioned.
754 has
  nextdown(+inf) is -nextup(-inf) (5.3.1)

18661 has
  canonicalize(SNAN): appears to be missing a domain error in
  the main body of the standard.
  Also, for F.10.8.7, canonicalize(SNAN) raises 'invalid'.
754 has
  convertFormat: no mention of SNAN in 5.4.2, but is implied by 6.2

Not sure about payload related functions as 754 keeps changing.

18661
  Would it be better if fesetexcept() returned the set of flags that
  were successfully set?
754
  raiseFlags() returns void (5.7.4)

18661
  fetestexceptflag() returns "OR" of two items; I think it should be
  "AND".  Also the order of the two arguments is switched from 754.
754
  returns a boolean (5.7.4)


---
Fred J. Tydeman        Tydeman Consulting
tydeman at tybor.com      Testing, numerics, programming
+1 (702) 608-6093      Vice-chair of PL22.11 (ANSI "C")
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