This is the mail archive of the glibc-bugs@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[Bug libc/17661] some invalid floating point values should be considered as "nan"


https://sourceware.org/bugzilla/show_bug.cgi?id=17661

--- Comment #7 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
Most libm functions are not using isnan - they generally examine bits of 
the representation directly, often in assembly code (and then e.g. select 
what to do based on the value of the exponent, assuming that the high 
mantissa bit is valid given those exponent bits).

It seems dubious to complicate lots of separate functions for inputs no 
valid program will ever pass in.  I'm not sure if the logical handling of 
the invalid values (i.e. handling consistent with what hardware operations 
do) is consistent between x86/x86_64, ia64, m68k either (certainly there 
are some differences between the Intel and m68k versions of the format, at 
least, which ldbl-96 code needs to allow for in some cases).

-- 
You are receiving this mail because:
You are on the CC list for the bug.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]