Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide

IEEE or HEXADEC

The DEFAULT(IEEE) option indicates that, by default, float data is to be held in native Intel style. When you specify the HEXADEC suboption, the compiler must execute significantly more instructions for most operations involving floating-point variables.

Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide