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unordered-signaling predicates and negations in IEEE 754-2008



Hi,

Section 5.11 page 29 of the IEEE 754-2008 standard:

  "Table 5.2 lists five unordered-signaling predicates and their
  negations that cause an invalid operation exception when the
  relation is unordered."

If I understand correctly, the exception is also signaled for the
negations, even though the UN relation is true. This seems to be
logical to me, but just above Table 5.2, the standard says:

  "The unordered-signaling predicates in Table 5.2, intended for
  use by programs not written to take into account the possibility
  of NaN operands, signal an invalid operation exception on quiet
  NaN operands:"

Shouldn't it say "The unordered-signaling predicates *and their
negations* ..."?

-- 
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.org/>
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Work: CR INRIA - computer arithmetic / Arenaire project (LIP, ENS-Lyon)


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