HP-UX Floating-Point Guide

126 Chapter 5

Manipulating the Floating-Point Status Register

The ﬂoating-point status register (also known as the ﬂoating-point

control register) stores information about several aspects of the

ﬂoating-point environment:

• The rounding mode

• What traps are enabled—that is, what exceptions your program can

catch

• If traps are not enabled, what exceptions have occurred

• Whether ﬂush-to-zero underﬂow mode is set (for systems that have

this capability)

• The model and revision of the system’s ﬂoating-point unit (FPU)

(also called the ﬂoating-point coprocessor)

HP-UX systems provide facilities that allow you to manipulate the status

you to retrieve any of this information or to modify the environment. The

+FP compiler option allows you to specify on the command line the traps

to enable for a particular program and the underﬂow mode.