Add a function to round a floatx80 to the defined precision
(floatx80_rounding_precision)
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Message-Id: <20170628204241.32106-5-laurent@vivier.eu>