Slitaz armhf -- Floating-Point Exceptions

IEEE 754 - This standard defines five types of floating-point exception that must be signaled when detected:
  • Invalid operation
  • Division by zero
  • Overflow
  • Underflow
  • Inexact calculation
When one of these exceptions occurs in a user process, it is signaled either by setting a flag or taking a trap. By default, the system sets a status flag in the Floating-Point Status and Control registers (FPSCR), indicating the exception has occurred. Once the status flags are set by an exception, they are cleared only when the process clears them explicitly or when the process ends. The operating system provides subroutines to query, set, or clear these flags.

The system can also cause the floating-point exception signal (SIGFPE) to be raised if a floating-point exception occurs. Because this is not the default behavior, the operating system provides subroutines to change the state of the process so the signal is enabled. When a floating-point exception raises the SIGFPE signal, the process terminates and produces a core file if no signal-handler subroutine is present in the process. Otherwise, the process calls the signal-handler subroutine.