Chapter 5 Manipulating the Floating-Point Status Register

Table of Contents

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 register. The fenv(5) suite, a group of C math library functions, allows 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.

Chapter 5 Manipulating the Floating-Point Status Register

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