Right justify A in a field of B spaces and place into C.
If Result < 0, trap execution.
Otherwise, perform the following operations in order:
Take the numeric interpretation of A.
That is, apply the rules given in Section
3.2.5 of MDC/28 to A.
If Result = 0, round the numeric value in A to an integer and
remove the decimal point.
Otherwise, round A to Result fraction
digits (pad with trailing zeros if necessary).