sysdeps/ieee754/ldbl-128ibm/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 #include <math_ldbl_opt.h>
  30
  31 long double __nextafterl(long double x, long double y)
  32 {
  33         int64_t hx,hy,ihx,ihy,ilx;
  34         u_int64_t lx;
  35         u_int64_t ly __attribute__ ((unused));
  36
  37         GET_LDOUBLE_WORDS64(hx,lx,x);
  38         GET_LDOUBLE_WORDS64(hy,ly,y);
  39         ihx = hx&0x7fffffffffffffffLL;          /* |hx| */
  40         ilx = lx&0x7fffffffffffffffLL;          /* |lx| */
  41         ihy = hy&0x7fffffffffffffffLL;          /* |hy| */
  42
  43         if((((ihx&0x7ff0000000000000LL)==0x7ff0000000000000LL)&&
  44             ((ihx&0x000fffffffffffffLL)!=0)) ||   /* x is nan */
  45            (((ihy&0x7ff0000000000000LL)==0x7ff0000000000000LL)&&
  46             ((ihy&0x000fffffffffffffLL)!=0)))     /* y is nan */
  47             return x+y; /* signal the nan */
  48         if(x==y)
  49             return y;           /* x=y, return y */
  50         if(ihx == 0 && ilx == 0) {                      /* x == 0 */
  51             long double u;
  52             hy = (hy & 0x8000000000000000ULL) | 1;
  53             SET_LDOUBLE_WORDS64(x,hy,0ULL);/* return +-minsubnormal */
  54             u = math_opt_barrier (x);
  55             u = u * u;
  56             math_force_eval (u);                /* raise underflow flag */
  57             return x;
  58         }
  59
  60         long double u;
  61         if(x > y) {     /* x > y, x -= ulp */
  62             if((hx==0xffefffffffffffffLL)&&(lx==0xfc8ffffffffffffeLL))
  63               return x+x;       /* overflow, return -inf */
  64             if (hx >= 0x7ff0000000000000LL) {
  65               SET_LDOUBLE_WORDS64(u,0x7fefffffffffffffLL,0x7c8ffffffffffffeLL);
  66               return u;
  67             }
  68             if(ihx <= 0x0360000000000000LL) {  /* x <= LDBL_MIN */
  69               u = math_opt_barrier (x);
  70               x -= __LDBL_DENORM_MIN__;
  71               if (ihx < 0x0360000000000000LL
  72                   || (hx > 0 && (int64_t) lx <= 0)
  73                   || (hx < 0 && (int64_t) lx > 1)) {
  74                 u = u * u;
  75                 math_force_eval (u);            /* raise underflow flag */
  76               }
  77               return x;
  78             }
  79             if (ihx < 0x06a0000000000000LL) { /* ulp will denormal */
  80               SET_LDOUBLE_WORDS64(u,(hx&0x7ff0000000000000LL),0ULL);
  81               u *= 0x1.0000000000000p-105L;
  82             } else
  83               SET_LDOUBLE_WORDS64(u,(hx&0x7ff0000000000000LL)-0x0690000000000000LL,0ULL);
  84             return x - u;
  85         } else {                                /* x < y, x += ulp */
  86             if((hx==0x7fefffffffffffffLL)&&(lx==0x7c8ffffffffffffeLL))
  87               return x+x;       /* overflow, return +inf */
  88             if ((u_int64_t) hx >= 0xfff0000000000000ULL) {
  89               SET_LDOUBLE_WORDS64(u,0xffefffffffffffffLL,0xfc8ffffffffffffeLL);
  90               return u;
  91             }
  92             if(ihx <= 0x0360000000000000LL) {  /* x <= LDBL_MIN */
  93               u = math_opt_barrier (x);
  94               x += __LDBL_DENORM_MIN__;
  95               if (ihx < 0x0360000000000000LL
  96                   || (hx > 0 && (int64_t) lx < 0 && lx != 0x8000000000000001LL)
  97                   || (hx < 0 && (int64_t) lx >= 0)) {
  98                 u = u * u;
  99                 math_force_eval (u);            /* raise underflow flag */
 100               }
 101               if (x == 0.0L)    /* handle negative __LDBL_DENORM_MIN__ case */
 102                 x = -0.0L;
 103               return x;
 104             }
 105             if (ihx < 0x06a0000000000000LL) { /* ulp will denormal */
 106               SET_LDOUBLE_WORDS64(u,(hx&0x7ff0000000000000LL),0ULL);
 107               u *= 0x1.0000000000000p-105L;
 108             } else
 109               SET_LDOUBLE_WORDS64(u,(hx&0x7ff0000000000000LL)-0x0690000000000000LL,0ULL);
 110             return x + u;
 111         }
 112 }
 113 strong_alias (__nextafterl, __nexttowardl)
 114 long_double_symbol (libm, __nextafterl, nextafterl);
 115 long_double_symbol (libm, __nexttowardl, nexttowardl);