sysdeps/ieee754/ldbl-128/s_ceill.c

   1 /* s_ceill.c -- long double version of s_ceil.c.
   2  */
   3
   4 /*
   5  * ====================================================
   6  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   7  *
   8  * Developed at SunPro, a Sun Microsystems, Inc. business.
   9  * Permission to use, copy, modify, and distribute this
  10  * software is freely granted, provided that this notice
  11  * is preserved.
  12  * ====================================================
  13  */
  14
  15 #if defined (LIBM_SCCS) && ! defined (lint)
  16 static char rcsid[] = "$NetBSD: $";
  17 #endif
  18
  19 /*
  20  * ceill(x)
  21  * Return x rounded toward -inf to integral value
  22  * Method:
  23  *      Bit twiddling.
  24  */
  25
  26 #define NO_MATH_REDIRECT
  27 #include <math.h>
  28 #include <math_private.h>
  29 #include <libm-alias-ldouble.h>
  30 #include <math-use-builtins.h>
  31
  32 _Float128
  33 __ceill (_Float128 x)
  34 {
  35 #if USE_CEILL_BUILTIN
  36   return __builtin_ceill (x);
  37 #else
  38   /* Use generic implementation.  */
  39   int64_t i0, i1, j0;
  40   uint64_t i, j;
  41   GET_LDOUBLE_WORDS64 (i0, i1, x);
  42   j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
  43   if (j0 < 48)
  44     {
  45       if (j0 < 0)
  46         {
  47           /* return 0 * sign (x) if |x| < 1  */
  48           if (i0 < 0)
  49             {
  50               i0 = 0x8000000000000000ULL;
  51               i1 = 0;
  52             }
  53           else if ((i0 | i1) != 0)
  54             {
  55               i0 = 0x3fff000000000000ULL;
  56               i1 = 0;
  57             }
  58         }
  59       else
  60         {
  61           i = (0x0000ffffffffffffULL) >> j0;
  62           if (((i0 & i) | i1) == 0)
  63             return x;           /* x is integral  */
  64           if (i0 > 0)
  65             i0 += (0x0001000000000000LL) >> j0;
  66           i0 &= (~i);
  67           i1 = 0;
  68         }
  69     }
  70   else if (j0 > 111)
  71     {
  72       if (j0 == 0x4000)
  73         return x + x;           /* inf or NaN  */
  74       else
  75         return x;               /* x is integral  */
  76     }
  77   else
  78     {
  79       i = -1ULL >> (j0 - 48);
  80       if ((i1 & i) == 0)
  81         return x;               /* x is integral  */
  82       if (i0 > 0)
  83         {
  84           if (j0 == 48)
  85             i0 += 1;
  86           else
  87             {
  88               j = i1 + (1LL << (112 - j0));
  89               if (j < i1)
  90                 i0 += 1;        /* got a carry  */
  91               i1 = j;
  92             }
  93         }
  94       i1 &= (~i);
  95     }
  96   SET_LDOUBLE_WORDS64 (x, i0, i1);
  97   return x;
  98 #endif /* ! USE_CEILL_BUILTIN  */
  99 }
 100 libm_alias_ldouble (__ceil, ceil)