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glibc  2.9
Functions
fraiseexcpt.c File Reference
#include <fenv_libc.h>
#include <sysdep.h>
#include <float.h>
#include <kernel-features.h>
#include "kernel_sysinfo.h"
#include <shlib-compat.h>

Go to the source code of this file.

Functions

int __feraiseexcept (int excepts)

Function Documentation

int __feraiseexcept ( int  excepts)

Definition at line 27 of file fraiseexcpt.c.

{
  INTERNAL_SYSCALL_DECL (err);
  unsigned long t = excepts;
  long r;

  r = INTERNAL_SYSCALL (osf_setsysinfo, err, 2, SSI_IEEE_RAISE_EXCEPTION, &t);

#ifndef __ASSUME_IEEE_RAISE_EXCEPTION
  if (!INTERNAL_SYSCALL_ERROR_P (r, err))
    return 0;

  double d;

  /* If we got an error from SSI_IEEE_RAISE_EXCEPTION, assume it means that
     the system call isn't actually implemented.  Do the best we can.  */

  /* Invalid implemented with 0 / 0 -> NaN.  */
  if (excepts & FE_INVALID)
    __asm__ __volatile__ ("divs/su $f31,$f31,%0; trapb" : "=f"(d) : );

  /* Division By Zero implemented with 1 / 0 -> NaN.  */
  if (excepts & FE_DIVBYZERO)
    __asm__ __volatile__ ("divs/su %1,$f31,%0; trapb" : "=&f"(d) : "f"(1.0f));

  /* Overflow and underflow cannot be had all by themselves.  We can
     generate them with arithmetic, but we always get INEXACT raised
     at the same time.  Prepare to undo.  */
  if ((excepts & (FE_OVERFLOW | FE_UNDERFLOW)) && !(excepts & FE_INEXACT))
    INTERNAL_SYSCALL (osf_getsysinfo, err, 2, GSI_IEEE_FP_CONTROL, &t);

  /* Overflow implemented with FLT_MAX + FLT_MAX -> Inf.  */
  if (excepts & FE_OVERFLOW)
    __asm__ __volatile__ ("adds/sui %1,%1,%0; trapb"
                       : "=&f"(d) : "f"(FLT_MAX));

  /* Underflow implemented with FLT_MIN * FLT_MIN -> 0.  */
  if (excepts & FE_UNDERFLOW)
    __asm__ __volatile__ ("muls/sui %1,%1,%0; trapb"
                       : "=&f"(d) : "f"(FLT_MIN));

  /* Inexact implemented with (long)0.5 -> 0.  */
  if ((excepts & (FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT)) == FE_INEXACT)
    __asm__ __volatile__ ("cvttq/svi %1,%0; trapb" : "=&f"(d) : "f"(0.5f));

  /* If we raised inexact when not asked, and inexact was not previously
     raised, then clear that exception.  */
  if ((excepts & (FE_OVERFLOW | FE_UNDERFLOW))
      && !((excepts | t) & FE_INEXACT))
    {
      t |= excepts & SWCR_STATUS_MASK;
      INTERNAL_SYSCALL (osf_setsysinfo, err, 2, SSI_IEEE_FP_CONTROL, &t);
    }
#endif /* !__ASSUME_IEEE_RAISE_EXCEPTION */

  return 0;
}

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