386BSD 0.1 development

[unix-history] / usr / src / usr.bin / awk / matherr.c

/********************************************
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 1.2  1992/06/02  05:07:35  rich
* Ported to 386bsd.  Changes from vax BSD4.3 include usage of
* fmod in libm.a, usage of void pointers, and usage of vfprintf
* in libc.a.  Floating point exceptions are not raised when
* they should be, which causes the last fpe test to fail.
*
* Revision 5.1  91/12/05  07:56:18  brennan
* 1.1 pre-release
* 
*/

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

#if   FPE_TRAPS_ON
#include <signal.h>

/* machine dependent changes might be needed here */

static void  fpe_catch( signal, why)
 int signal, why ;
{

#if   NOINFO_SIGFPE
/* some systems give no hook to find out what the exception
   was -- stuff like this is why people still use fortran 

   If this fits, #define NOINFO_SIGFPE 1 in  your config.h
*/
 rt_error("floating point exception, probably overflow") ;
#else

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

   case FPE_INTOVF_TRAP :
   case FPE_FLTOVF_TRAP :
      rt_error("floating point overflow") ;

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

void   fpe_init()
{ (void) signal(SIGFPE, fpe_catch) ; }

#else  /* FPE_TRAPS_ON==0 */

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

#if  HAVE_MATHERR

#if  ! 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 */

#endif   /*  HAVE_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