[cfp-interest 3605] Re: Rounding Mode

[David Hough CFP]

Rounding precision is a mode on extended precision implementations like x87
and mc6888x which allowed extended precision operations to round more like 
double or single precision.     It's helpful at times when computing 
elementary functions in extended precision, then rounding to final precision.
So it needs a uniform higher level language syntax.
As I recall, in C it is a no-op on platforms that don't offer it.