[PATCH 0/5] x86 pseudo-normal numbers

[Joseph Myers]

On Tue, 15 Dec 2020, Siddhesh Poyarekar via Libc-alpha wrote:

> Pseudo-denormal numbers are not catered for in this patch.  The x86 CPU
> supposedly treats these numbers as denormals, but both gcc and glibc
> currently treat them as normals.

The CPU treats them as denormals in that it signals the (x86-specific) 
"denormal operand" exception for them, but otherwise treats them as if the 
biased exponent were 1.  Since the "denormal operand" exception is not 
part of ISO C or FE_ALL_EXCEPT and glibc does not attempt to produce any 
particular semantics for when it is raised, making glibc handle them the 
same as the processor does means handling them the same as the 
corresponding normal representations.

-- 
Joseph S. Myers
joseph@codesourcery.com