pslachkieee_()

void pslachkieee_	(	Int *	isieee,
		float *	rmax,
		float *	rmin
	)

Definition at line 145 of file pslaiect.c.

{
/* 
*
*  Purpose
*  ======= 
*
*  pslachkieee performs a simple check to make sure that the features
*  of the IEEE standard that we rely on are implemented.  In some
*  implementations, pslachkieee may not return.
*
*  Note that all arguments are call-by-reference so that this routine
*  can be directly called from Fortran code.
*
*  This is a ScaLAPACK internal subroutine and arguments are not
*  checked for unreasonable values.
*
*  Arguments
*  =========
*
*  ISIEEE   (local output) INTEGER
*           On exit, ISIEEE = 1 implies that all the features of the
*           IEEE standard that we rely on are implemented.
*           On exit, ISIEEE = 0 implies that some the features of the
*           IEEE standard that we rely on are missing.
*
*  RMAX     (local input) REAL
*           The overflow threshold ( = SLAMCH('O') ).
*
*  RMIN     (local input) REAL
*           The underflow threshold ( = SLAMCH('U') ).
*
*  =====================================================================
*
*  .. Local Scalars ..
*/
   float x, pinf, pzero, ninf, nzero;
   Int         ieflag, *ix, sbit1, sbit2, negone=-1, errornum;
/* ..
*  .. Executable Statements ..
*/
 
   pslasnbt_( &ieflag );
 
   pinf = *rmax / *rmin;
   pzero = 1.0 / pinf;
   pinf = 1.0 / pzero;
 
   if( pzero != 0.0 ){
      printf("pzero = %g should be zero\n",pzero);
      *isieee = 0; 
      return ;
   }
   if( ieflag == 1 ){
      sbit1 = (*((Int *)&pzero) >> 31) & 1;
      sbit2 = (*((Int *)&pinf) >> 31) & 1;
   }
   if( sbit1 == 1 ){
      printf("Sign of positive infinity is incorrect\n");
      *isieee = 0;
   }
   if( sbit2 == 1 ){
      printf("Sign of positive zero is incorrect\n");
      *isieee = 0;
   }
 
   ninf = -pinf;
   nzero = 1.0 / ninf;
   ninf = 1.0 / nzero;
 
   if( nzero != 0.0 ){
      printf("nzero = %g should be zero\n",nzero);
      *isieee = 0;
   }
   if( ieflag == 1 ){
      sbit1 = (*((Int *)&nzero) >> 31) & 1;
      sbit2 = (*((Int *)&ninf) >> 31) & 1;
   }
   if( sbit1 == 0 ){
      printf("Sign of negative infinity is incorrect\n");
      *isieee = 0;
   }
   if( sbit2 == 0 ){
      printf("Sign of negative zero is incorrect\n");
      *isieee = 0;
   }
}

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