https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113455
--- Comment #1 from Joseph S. Myers <jsm28 at gcc dot gnu.org> --- The decimal rounding mode is set with fe_dec_setround. libdfp provides that function and an fenv.h wrapper with constant definitions including FE_DEC_TONEARESTFROMZERO. Providing that library is outside the scope of GCC; see https://sourceware.org/pipermail/libc-alpha/2019-September/106579.html for a discussion of considerations for any integration of such support directly in glibc (which would certainly be a lot of work). libdfp is at https://github.com/libdfp/libdfp but doesn't have that much activity.
