libm support for ARMv7 and VSQRT?

[Richard Earnshaw (lists)]

On 20/03/17 06:52, Sebastian Huber wrote:
> Hello,
> 
> there is some ARM-specific libm support for ARMv8:
> 
> https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=tree;f=newlib/libm/machine/arm;h=5457f11619b2d67e8f56f352afb404c06a12c2bb;hb=HEAD
> 
> 
> The VFPv2+ supports a VSQRT instruction. Would it make sense to use it
> for the sqrt() implementation, similar to
> 
> https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=blob;f=newlib/libm/machine/aarch64/e_sqrt.c;h=e4b7554ac1811bf04f726da198b913c0c30595ca;hb=HEAD
> 
> https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=blob;f=newlib/libm/machine/aarch64/ef_sqrt.c;h=19fec952517769ad3851efef3b11dc6c02fb7582;hb=HEAD
> 
> 
> ?
> 

I'm sure a patch would be welcome :-)

Don't forget, however, that you also need to deal with the soft-float
case (something the aarch64 code does not have to worry about).

R.