text: /****************************************************************************
   * libc/math/lib_truncl.c
   *
   * This implementation is derived from the musl library under the MIT License
   *
   * Copyright © 2005-2014 Rich Felker, et al.
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
   * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
   * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
   * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  #include <nuttx/compiler.h>
  
  #include <stdint.h>
  #include <float.h>
  #include <math.h>
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  #ifdef CONFIG_HAVE_LONG_DOUBLE
  static const long double toint = 1 / LDBL_EPSILON;
  
  /* FIXME This will only work if long double is 64 bit and little endian */
  
  union ldshape
  {
    long double f;
    struct
      {
        uint64_t m;
        uint16_t se;
      } i;
  };
  
  long double truncl(long double x)
  {
    union ldshape u =
    {
      x
    };
    int e = u.i.se & 0x7fff;
    int s = u.i.se >> 15;
    long double y;
    volatile long double __x;
  
    if (e >= 0x3fff + LDBL_MANT_DIG - 1)
      {
        return x;
      }
  
    if (e <= 0x3fff - 1)
      {
        /* Force Eval */
  
        __x = (x + 0x1p120f);
        (void)__x;
        return x*0;
      }
  
    /* y = int(|x|) - |x|, where int(|x|) is an integer neighbor of |x| */
  
    if (s)
      {
        x = -x;
      }
  
    y = x + toint - toint - x;
    if (y > 0)
      {
        y -= 1;
      }
  
    x += y;
    return s ? -x : x;
  }
  #endif
  