incorrectly rounded square root
Wed Jun 2 19:12:09 GMT 2021
On Wed, Jun 2, 2021, 2:08 PM Marco Atzeri <email@example.com> wrote:
> On 02.06.2021 20:43, Jeff Johnston wrote:
> > On Wed, Jun 2, 2021 at 9:08 AM Joel Sherrill <firstname.lastname@example.org> wrote:
> >> On Wed, Jun 2, 2021 at 2:51 AM Paul Zimmermann <
> >> wrote:
> > I'll second Joel's comment. The code is extremely close to the glibc
> > both in sqrtf and fesetround. The only
> > thing I can think of is that the glibc code does the x87 stuff first and
> > does the set back into FPU state before doing the
> > SSE stuff. The newlib code sets back the FPU state at the end after the
> > SSE stuff. Don't know if this is relevant or not.
> > Any Cygwin users out there who can verify that the code is working/not
> > working for them?
> > -- Jeff J.
> current Cygwin produces for both i686 and X86_64
> $ gcc -DNEWLIB -fno-builtin test_sqrt.c -lm
> $ ./a.exe
> RNDN: 0x1.ff83fp+63
> RNDZ: 0x1.ff83fp+63
> RNDU: 0x1.ff83fp+63
> RNDD: 0x1.ff83fp+63
Does fegetround() return different values based on what mode was set?
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