1  /* s_nextafterl.c -- long double version of s_nextafter.c.
       2   * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
       3   */
       4  
       5  /*
       6   * ====================================================
       7   * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
       8   *
       9   * Developed at SunPro, a Sun Microsystems, Inc. business.
      10   * Permission to use, copy, modify, and distribute this
      11   * software is freely granted, provided that this notice
      12   * is preserved.
      13   * ====================================================
      14   */
      15  
      16  #if defined(LIBM_SCCS) && !defined(lint)
      17  static char rcsid[] = "$NetBSD: $";
      18  #endif
      19  
      20  /* IEEE functions
      21   *	nextafterq(x,y)
      22   *	return the next machine floating-point number of x in the
      23   *	direction toward y.
      24   *   Special cases:
      25   */
      26  
      27  #include "quadmath-imp.h"
      28  
      29  __float128 nextafterq(__float128 x, __float128 y)
      30  {
      31  	int64_t hx,hy,ix,iy;
      32  	uint64_t lx,ly;
      33  
      34  	GET_FLT128_WORDS64(hx,lx,x);
      35  	GET_FLT128_WORDS64(hy,ly,y);
      36  	ix = hx&0x7fffffffffffffffLL;		/* |x| */
      37  	iy = hy&0x7fffffffffffffffLL;		/* |y| */
      38  
      39  	if(((ix>=0x7fff000000000000LL)&&((ix-0x7fff000000000000LL)|lx)!=0) ||   /* x is nan */
      40  	   ((iy>=0x7fff000000000000LL)&&((iy-0x7fff000000000000LL)|ly)!=0))     /* y is nan */
      41  	   return x+y;
      42  	if(x==y) return y;		/* x=y, return y */
      43  	if((ix|lx)==0) {			/* x == 0 */
      44  	    __float128 u;
      45  	    SET_FLT128_WORDS64(x,hy&0x8000000000000000ULL,1);/* return +-minsubnormal */
      46  	    u = math_opt_barrier (x);
      47  	    u = u * u;
      48  	    math_force_eval (u);		/* raise underflow flag */
      49  	    return x;
      50  	}
      51  	if(hx>=0) {			/* x > 0 */
      52  	    if(hx>hy||((hx==hy)&&(lx>ly))) {	/* x > y, x -= ulp */
      53  		if(lx==0) hx--;
      54  		lx--;
      55  	    } else {				/* x < y, x += ulp */
      56  		lx++;
      57  		if(lx==0) hx++;
      58  	    }
      59  	} else {				/* x < 0 */
      60  	    if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */
      61  		if(lx==0) hx--;
      62  		lx--;
      63  	    } else {				/* x > y, x += ulp */
      64  		lx++;
      65  		if(lx==0) hx++;
      66  	    }
      67  	}
      68  	hy = hx&0x7fff000000000000LL;
      69  	if(hy==0x7fff000000000000LL) {
      70  	    __float128 u = x + x;		/* overflow  */
      71  	    math_force_eval (u);
      72  	    errno = ERANGE;
      73  	}
      74  	if(hy==0) {
      75  	    __float128 u = x*x;		/* underflow */
      76  	    math_force_eval (u);		/* raise underflow flag */
      77  	    errno = ERANGE;
      78  	}
      79  	SET_FLT128_WORDS64(x,hx,lx);
      80  	return x;
      81  }