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 #ifdef __STDC__
  32         long double __nextafterl(long double x, long double y)
  33 #else
  34         long double __nextafterl(x,y)
  35         long double x,y;
  36 #endif
  37 {
  38         int64_t hx,hy,ihx,ihy,ilx;
  39         u_int64_t lx,ly;
  40
  41         GET_LDOUBLE_WORDS64(hx,lx,x);
  42         GET_LDOUBLE_WORDS64(hy,ly,y);
  43         ihx = hx&0x7fffffffffffffffLL;          /* |hx| */
  44         ilx = lx&0x7fffffffffffffffLL;          /* |lx| */
  45         ihy = hy&0x7fffffffffffffffLL;          /* |hy| */
  46
  47         if((((ihx&0x7ff0000000000000LL)==0x7ff0000000000000LL)&&
  48             ((ihx&0x000fffffffffffffLL)!=0)) ||   /* x is nan */
  49            (((ihy&0x7ff0000000000000LL)==0x7ff0000000000000LL)&&
  50             ((ihy&0x000fffffffffffffLL)!=0)))     /* y is nan */
  51             return x+y; /* signal the nan */
  52         if(x==y)
  53             return y;           /* x=y, return y */
  54         if(ihx == 0 && ilx == 0) {                      /* x == 0 */
  55             long double u;
  56             hy = (hy & 0x8000000000000000ULL) | 1;
  57             SET_LDOUBLE_WORDS64(x,hy,0ULL);/* return +-minsubnormal */
  58             u = math_opt_barrier (x);
  59             u = u * u;
  60             math_force_eval (u);                /* raise underflow flag */
  61             return x;
  62         }
  63
  64         long double u;
  65         if(x > y) {     /* x > y, x -= ulp */
  66             if((hx==0xffefffffffffffffLL)&&(lx==0xfc8ffffffffffffeLL))
  67               return x+x;       /* overflow, return -inf */
  68             if (hx >= 0x7ff0000000000000LL) {
  69               SET_LDOUBLE_WORDS64(u,0x7fefffffffffffffLL,0x7c8ffffffffffffeLL);
  70               return u;
  71             }
  72             if(ihx <= 0x0360000000000000LL) {  /* x <= LDBL_MIN */
  73               u = math_opt_barrier (x);
  74               x -= __LDBL_DENORM_MIN__;
  75               if (ihx < 0x0360000000000000LL
  76                   || (hx > 0 && (int64_t) lx <= 0)
  77                   || (hx < 0 && (int64_t) lx > 1)) {
  78                 u = u * u;
  79                 math_force_eval (u);            /* raise underflow flag */
  80               }
  81               return x;
  82             }
  83             if (ihx < 0x06a0000000000000LL) { /* ulp will denormal */
  84               SET_LDOUBLE_WORDS64(u,(hx&0x7ff0000000000000LL),0ULL);
  85               u *= 0x1.0000000000000p-105L;
  86             } else
  87               SET_LDOUBLE_WORDS64(u,(hx&0x7ff0000000000000LL)-0x0690000000000000LL,0ULL);
  88             return x - u;
  89         } else {                                /* x < y, x += ulp */
  90             if((hx==0x7fefffffffffffffLL)&&(lx==0x7c8ffffffffffffeLL))
  91               return x+x;       /* overflow, return +inf */
  92             if ((u_int64_t) hx >= 0xfff0000000000000ULL) {
  93               SET_LDOUBLE_WORDS64(u,0xffefffffffffffffLL,0xfc8ffffffffffffeLL);
  94               return u;
  95             }
  96             if(ihx <= 0x0360000000000000LL) {  /* x <= LDBL_MIN */
  97               u = math_opt_barrier (x);
  98               x += __LDBL_DENORM_MIN__;
  99               if (ihx < 0x0360000000000000LL
 100                   || (hx > 0 && (int64_t) lx < 0 && lx != 0x8000000000000001LL)
 101                   || (hx < 0 && (int64_t) lx >= 0)) {
 102                 u = u * u;
 103                 math_force_eval (u);            /* raise underflow flag */
 104               }
 105               if (x == 0.0L)    /* handle negative __LDBL_DENORM_MIN__ case */
 106                 x = -0.0L;
 107               return x;
 108             }
 109             if (ihx < 0x06a0000000000000LL) { /* ulp will denormal */
 110               SET_LDOUBLE_WORDS64(u,(hx&0x7ff0000000000000LL),0ULL);
 111               u *= 0x1.0000000000000p-105L;
 112             } else
 113               SET_LDOUBLE_WORDS64(u,(hx&0x7ff0000000000000LL)-0x0690000000000000LL,0ULL);
 114             return x + u;
 115         }
 116 }
 117 strong_alias (__nextafterl, __nexttowardl)
 118 long_double_symbol (libm, __nextafterl, nextafterl);
 119 long_double_symbol (libm, __nexttowardl, nexttowardl);