sysdeps/ieee754/ldbl-128/s_rintl.c

   1 /* s_rintl.c -- long double version of s_rint.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  * rintl(x)
  21  * Return x rounded to integral value according to the prevailing
  22  * rounding mode.
  23  * Method:
  24  *      Using floating addition.
  25  * Exception:
  26  *      Inexact flag raised if x not equal to rintl(x).
  27  */
  28
  29 #define NO_MATH_REDIRECT
  30 #include <math.h>
  31 #include <math_private.h>
  32 #include <libm-alias-ldouble.h>
  33 #include <math-use-builtins.h>
  34
  35 _Float128
  36 __rintl (_Float128 x)
  37 {
  38 #if USE_RINTL_BUILTIN
  39   return __builtin_rintl (x);
  40 #else
  41   /* Use generic implementation.  */
  42   static const _Float128
  43     TWO112[2] = {
  44                  5.19229685853482762853049632922009600E+33L, /* 0x406F000000000000, 0 */
  45                  -5.19229685853482762853049632922009600E+33L  /* 0xC06F000000000000, 0 */
  46   };
  47   int64_t i0, j0, sx;
  48   uint64_t i1 __attribute__ ((unused));
  49   _Float128 w, t;
  50   GET_LDOUBLE_WORDS64 (i0, i1, x);
  51   sx = (((uint64_t) i0) >> 63);
  52   j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
  53   if (j0 < 112)
  54     {
  55       if (j0 < 0)
  56         {
  57           w = TWO112[sx] + x;
  58           t = w - TWO112[sx];
  59           GET_LDOUBLE_MSW64 (i0, t);
  60           SET_LDOUBLE_MSW64 (t, (i0 & 0x7fffffffffffffffLL) | (sx << 63));
  61           return t;
  62         }
  63     }
  64   else
  65     {
  66       if (j0 == 0x4000)
  67         return x + x;           /* inf or NaN  */
  68       else
  69         return x;               /* x is integral  */
  70     }
  71   w = TWO112[sx] + x;
  72   return w - TWO112[sx];
  73 #endif /* ! USE_RINTL_BUILTIN  */
  74 }
  75 libm_alias_ldouble (__rint, rint)