[std-interval] Revised document available
Gabriel Dos Reis
gdr at integrable-solutions.net
Wed Sep 20 16:44:26 PDT 2006
Guillaume Melquiond <guillaume.melquiond at ens-lyon.fr> writes:
| Le lundi 18 septembre 2006 à 22:48 +0100, Dr John Pryce a écrit :
| > Dear std-intervalers,
| > B.
| > I do not feel the text makes it clear whether the
| > platform's arithmetic MUST support oo - which
| > more or less amounts to using IEEE arithmetic.
| Unless I'm mistaken, infinities are mandated by LIA-1 (Language
| Independent Arithmetic 1)
LIA-1 does NOT mandate infinities.
What LIA-1 says is (section 5.2.9 Conformity to IEC 559)
# The parameter iec_559 shall be true only when the type F
# completely conforms to the requirements of IEC 559 (also known as
# IEEE 754). Fa may correspond to any of the floating point types
# defined in IEC 559.
A further note following the above statement
# NOTE 1 -- The IEC 559 facilities include values for infinities and
# NaNs, extended comparisons, program control of rounding, an
# inexact exception flag, and so oon. See annex C for more
Last and not least, you have to read section "A.220.127.116.11 Infinity and NaNs"
from Appendix A:
# [...] Therefore, LAI-1 makes no provision for infinity or NaNs.
# The behavior of operations with an infinity ro a NaN as input is
# not defined by LIA-1. owever, be sure to read 5.2.9 and clause C.1
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