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glibc  2.9
Functions
fraiseexcpt.c File Reference
#include <fenv.h>
#include <float.h>
#include <math.h>
#include <signal.h>
#include <unistd.h>

Go to the source code of this file.

Functions

int feraiseexcept (int excepts)

Function Documentation

int feraiseexcept ( int  excepts)

Definition at line 29 of file fraiseexcpt.c.

{
  double tmp;
  double dummy;

  /* Raise exceptions represented by EXPECTS.  But we must raise only
     one signal at a time.  It is important the if the overflow/underflow
     exception and the inexact exception are given at the same time,
     the overflow/underflow exception precedes the inexact exception.  */

  /* We do these bits in assembly to be certain GCC doesn't optimize
     away something important.  */

  /* First: invalid exception.  */
  if (FE_INVALID & excepts)
    {
      /* One example of a invalid operation is 0 * Infinity.  */
      tmp = 0;
      __asm__ __volatile__ ("frcpa.s0 %0,p1=f0,f0" : "=f" (tmp) : : "p1" );
    }

  /* Next: division by zero.  */
  if (FE_DIVBYZERO & excepts)
    __asm__ __volatile__ ("frcpa.s0 %0,p1=f1,f0" : "=f" (tmp) : : "p1" );

  /* Next: overflow.  */
  if (FE_OVERFLOW & excepts)
    {
      dummy = DBL_MAX;

      __asm__ __volatile__ ("fadd.d.s0 %0=%1,%1" : "=f" (dummy) : "0" (dummy));
    }

  /* Next: underflow.  */
  if (FE_UNDERFLOW & excepts)
    {
      dummy = DBL_MIN;

      __asm__ __volatile__ ("fnma.d.s0 %0=%1,%1,f0" : "=f" (tmp) : "f" (dummy));
  }

  /* Last: inexact.  */
  if (FE_INEXACT & excepts)
    {
      dummy = DBL_MAX;
      __asm__ __volatile__ ("fsub.d.s0 %0=%1,f1" : "=f" (dummy) : "0" (dummy));
    }

  /* Success.  */
  return 0;
}

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