FloatMode is located in:
float/src/SUN386/FloatMode.m3
float/src/SPARC/FloatMode.m3
float/src/SOLsun/FloatMode.m3
float/src/VAX/FloatMode.m3
float/src/IRIX5/FloatMode.m3
float/src/IEEE-default/FloatMode.m3
float/src/DS3100/FloatMode.m3