faster expf128

Joseph Myers
Mon Jun 29 22:39:50 GMT 2020

On Fri, 26 Jun 2020, Szabolcs Nagy wrote:

> > There is no expectation that most libm functions (other than those such as 
> > fma and sqrt that are fully defined by the corresponding IEEE operations) 
> > set inexact correctly.  (It is necessary to set other exceptions 
> > correctly, and the glibc testsuite verifies that; for expf128, that's 
> > invalid (for signaling NaNs), overflow and underflow.)
> and presumably target specific exceptions are not considered.
> (e.g. input denormal on x86)

Indeed, there are no expectations that libm functions do anything in 
particular with those.  (Those <fenv.h> functions that manipulate the 
whole environment, such as fegetenv and fesetenv, should still save and 
restore such architecture-specific state.)

Joseph S. Myers

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