sysdeps/ieee754/ldbl-128/s_nextafterl.c

   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  *      nextafterl(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 "math.h"
  28 #include "math_private.h"
  29
  30 #ifdef __STDC__
  31         long double __nextafterl(long double x, long double y)
  32 #else
  33         long double __nextafterl(x,y)
  34         long double x,y;
  35 #endif
  36 {
  37         int64_t hx,hy,ix,iy;
  38         u_int64_t lx,ly;
  39
  40         GET_LDOUBLE_WORDS64(hx,lx,x);
  41         GET_LDOUBLE_WORDS64(hy,ly,y);
  42         ix = hx&0x7fffffffffffffffLL;           /* |x| */
  43         iy = hy&0x7fffffffffffffffLL;           /* |y| */
  44
  45         if(((ix>=0x7fff000000000000LL)&&((ix-0x7fff000000000000LL)|lx)!=0) ||   /* x is nan */
  46            ((iy>=0x7fff000000000000LL)&&((iy-0x7fff000000000000LL)|ly)!=0))     /* y is nan */
  47            return x+y;
  48         if(x==y) return y;              /* x=y, return y */
  49         if((ix|lx)==0) {                        /* x == 0 */
  50             SET_LDOUBLE_WORDS64(x,hy&0x8000000000000000ULL,1);/* return +-minsubnormal */
  51             y = x*x;
  52             if(y==x) return y; else return x;   /* raise underflow flag */
  53         }
  54         if(hx>=0) {                     /* x > 0 */
  55             if(hx>hy||((hx==hy)&&(lx>ly))) {    /* x > y, x -= ulp */
  56                 if(lx==0) hx--;
  57                 lx--;
  58             } else {                            /* x < y, x += ulp */
  59                 lx++;
  60                 if(lx==0) hx++;
  61             }
  62         } else {                                /* x < 0 */
  63             if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */
  64                 if(lx==0) hx--;
  65                 lx--;
  66             } else {                            /* x > y, x += ulp */
  67                 lx++;
  68                 if(lx==0) hx++;
  69             }
  70         }
  71         hy = hx&0x7fff000000000000LL;
  72         if(hy==0x7fff000000000000LL) return x+x;/* overflow  */
  73         if(hy==0) {                             /* underflow */
  74             y = x*x;
  75             if(y!=x) {          /* raise underflow flag */
  76                 SET_LDOUBLE_WORDS64(y,hx,lx);
  77                 return y;
  78             }
  79         }
  80         SET_LDOUBLE_WORDS64(x,hx,lx);
  81         return x;
  82 }
  83 weak_alias (__nextafterl, nextafterl)
  84 strong_alias (__nextafterl, __nexttowardl)
  85 weak_alias (__nextafterl, nexttowardl)