math function accuracy -- was text2interval again /
Richard Fateman wrote:
> My current understanding is that:
> All those functions (sin, cos, and many friends)
> are merely recommended in 754-2008. Not required.
> If they are included, they must be correctly rounded.
Replace "included" with "supported". Technically an implementation
can provide functions (such as a slightly sloppy sin() function) and
be 754-2008-compliant as long as it does not claim to "support" these
functions (in the sense of "support" as defined in 754-2008).
For example, the AIX 7.1 libc is compliant with respect to double
arithmetic and conversions, but not most <math.h> functions. (The
AIX long double format is not an IEEE format, so there the issue
is moot, though my long double conversions extrapolate the 754-2008
rules to long double by treating them as if they had a precision of
106 bits, for most purposes.)
Michel.
---Sent: 2013-03-09 18:57:28 UTC