i386 and x86_64 fenv support

Corinna Vinschen vinschen@redhat.com
Tue Aug 27 15:39:00 GMT 2019

On Aug 27 08:31, Joel Sherrill wrote:
> Hi
> Earlier we discussed moving the winsup fenv.h files to newlib. Splitting
> winsup/cygwin/include/fenv.h to create a sys/fenv.h looks easy enough.
> But I have some status and a question after tinkering with this code out
> of tree and compiling with the RTEMS i386 and x86_64
> It includes winsup.h and wincap.h but it doesn't need them.

Yeah, that's kind of a boilerplate include in Cygwin code.  Just scratch
it, it can't be overly important for the fenv functionality.

> [...]
> There are prototypes for fegetprec() and fesetprec(). I think the
> prototypes need to move to the shared fenv.h and commented
> stubs for the constants needs to be in the shared dummy sys/fenv.h.
> Does this sound right?

As far as I can see, none of Linux or BSD have these functions.  It may
be the right thing to do to keep them local to Cygwin since they never
made it into a standard or one of the systems we're interested in here.

Ideally they are never defined in a header, not even on Cygwin.  We only
have to keep exporting these symbols in Cygwin for backward compat.

> My remaining issue is that it appears that i386 and x86_64 will need to
> share the same files. Do I just copy the files to both machine directories?
> I don't know if newlib's build infrastructure supports putting it in one
> place and using it in another architecture.

Shouldn't a symlink from x86_64/file to ../i386/file work?  git handles
symlinks just fine.


Corinna Vinschen
Cygwin Maintainer
Red Hat
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