/********************************************
matherr.c
copyright 1991, Michael D. Brennan

This is a source file for mawk, an implementation of
the AWK programming language.

Mawk is distributed without warranty under the terms of
the GNU General Public License, version 2, 1991.
********************************************/

/*$Log: matherr.c,v $
 *Revision 1.9  1996/09/01 16:54:35  mike
 *Third try at bug fix for solaris strtod.
 *
 * Revision 1.6  1994/12/18  20:53:43  mike
 * check NetBSD mathlib defines
 *
 * Revision 1.5  1994/12/14  14:48:57  mike
 * add <siginfo.h> include -- sysV doesn't have it inside <signal.h>
 * restore #else that had been removed
 *
 * Revision 1.4  1994/10/11  00:36:17  mike
 * systemVr4 siginfo
 *
 * Revision 1.3  1993/07/17  13:23:04  mike
 * indent and general code cleanup
 *
 * Revision 1.2	 1993/07/04  12:52:03  mike
 * start on autoconfig changes
 *
 * Revision 5.2	 1992/03/31  16:14:44  brennan
 * patch2:
 * TURN_ON_FPE_TRAPS() macro
 * USE_IEEEFP_H macro
 *
 * Revision 5.1	 91/12/05  07:56:18  brennan
 * 1.1 pre-release
 *
*/

#include  "mawk.h"
#include  <math.h>

/* Sets up NetBSD 1.0A for ieee floating point */
#if defined(_LIB_VERSION_TYPE) && defined(_LIB_VERSION) && defined(_IEEE_)
_LIB_VERSION_TYPE _LIB_VERSION = _IEEE_;
#endif

#ifdef	USE_IEEEFP_H
#include <ieeefp.h>
#ifdef   HAVE_STRTOD_OVF_BUG
static fp_except entry_mask ;
static fp_except working_mask ;
#endif
#endif

#ifndef	 TURN_OFF_FPE_TRAPS
#define	 TURN_OFF_FPE_TRAPS()	/* nothing */
#endif

#ifndef	 TURN_ON_FPE_TRAPS
#define	 TURN_ON_FPE_TRAPS()	/* nothing */
#endif

#ifdef  SV_SIGINFO
#include <siginfo.h>
#define  FPE_ZERODIVIDE  FPE_FLTDIV
#define  FPE_OVERFLOW    FPE_FLTOVF
#endif

#ifdef	 FPE_TRAPS_ON
#include <signal.h>

/* machine dependent changes might be needed here */

#ifdef   SV_SIGINFO
static void
fpe_catch(signal, sip)
   int signal; 
   siginfo_t *sip ;
{
   int why = sip->si_code ;

#else

static void
fpe_catch(signal, why)
   int signal, why ;
{
#endif /* SV_SIGINFO  */

#if   NOINFO_SIGFPE
   rt_error("floating point exception, probably overflow") ;
   /* does not return */
#else

   switch (why)
   {
      case FPE_ZERODIVIDE:
	 rt_error("division by zero") ;

      case FPE_OVERFLOW:
	 rt_error("floating point overflow") ;

      default:
	 rt_error("floating point exception") ;
   }
#endif /* noinfo_sigfpe */
}

void
fpe_init()
{
   TURN_ON_FPE_TRAPS() ;

#ifndef  SV_SIGINFO
   signal(SIGFPE, fpe_catch) ;

#else
   { struct sigaction x ;

     memset(&x, 0, sizeof(x)) ;
     x.sa_handler = fpe_catch ;
     x.sa_flags = SA_SIGINFO ;

     sigaction(SIGFPE, &x, (struct sigaction*)0) ;
   }
#endif

#ifdef  HAVE_STRTOD_OVF_BUG
   /* we've already turned the traps on */
   working_mask = fpgetmask() ;
   entry_mask = working_mask & ~FP_X_DZ & ~FP_X_OFL ;
#endif
}

#else /* FPE_TRAPS not defined */

void
fpe_init()
{
   TURN_OFF_FPE_TRAPS() ;
}
#endif

#ifndef	 NO_MATHERR

#ifndef	 FPE_TRAPS_ON

/* If we are not trapping math errors, we will shutup the library calls
*/

int
matherr(e)
   struct exception *e ;
{
   return 1 ;
}

#else /* print error message and exit */

int
matherr(e)
   struct exception *e ;
{
   char *error ;

   switch (e->type)
   {
      case DOMAIN:
      case SING:
	 error = "domain error" ;
	 break ;

      case OVERFLOW:
	 error = "overflow" ;
	 break ;

      case TLOSS:
      case PLOSS:
	 error = "loss of significance" ;
	 break ;

      case UNDERFLOW:
	 e->retval = 0.0 ;
	 return 1 ;		 /* ignore it */
   }

   if (strcmp(e->name, "atan2") == 0)  rt_error("atan2(%g,%g) : %s",
	       e->arg1, e->arg2, error) ;
   else	 rt_error("%s(%g) : %s", e->name, e->arg1, error) ;

   /* won't get here */
   return 0 ;
}
#endif /* FPE_TRAPS_ON */

#endif /*  ! no matherr */


/* this is how one gets the libm calls to do the right
thing on bsd43_vax
*/

#ifdef	 BSD43_VAX

#include <errno.h>

double	infnan(arg)
   int arg ;
{
   switch (arg)
   {
	 case  ERANGE : errno = ERANGE ; return HUGE ;
	 case -ERANGE : errno = EDOM ; return -HUGE ;
      default:
	 errno = EDOM ;
   }
   return 0.0 ;
}

#endif /* BSD43_VAX */

/* This routine is for XENIX-68K 2.3A.
    Error check routine to be called after fp arithmetic.
*/

#if SW_FP_CHECK
/* Definitions of bit values in iserr() return value */

#define OVFLOW		2
#define UFLOW		4
#define ZERODIV		8
#define OVFLFIX		32
#define INFNAN		64

void
fpcheck()
{
   register int fperrval ;
   char *errdesc ;

   if ((fperrval = iserr()) == 0)
      return ;			 /* no error */

   errdesc = (char *) 0 ;

   if (fperrval & INFNAN)  errdesc = "arg is infinity or NAN" ;
   else if (fperrval & ZERODIV)	 errdesc = "division by zero" ;
   else if (fperrval & OVFLOW)	errdesc = "overflow" ;
   else if (fperrval & UFLOW) ; /* ignored */

   if (errdesc)	 rt_error("%s", errdesc) ;
}

#endif

#ifdef HAVE_STRTOD_OVF_BUG
/* buggy strtod in solaris, probably any sysv with ieee754
   strtod can generate an fpe  */

double
strtod_with_ovf_bug(s, ep)
   const char *s ;
   char **ep ;
{
   double ret ;

   fpsetmask(entry_mask) ;  /* traps off */
#undef strtod               /* make real strtod visible */
   ret = strtod(s, ep) ;
   fpsetmask(working_mask) ; /* traps on */
   return ret ;
}
#endif