1  /*
  2   * Copyright (C) 2008-2020 Advanced Micro Devices, Inc. All rights reserved.
  3   *
  4   * Redistribution and use in source and binary forms, with or without modification,
  5   * are permitted provided that the following conditions are met:
  6   * 1. Redistributions of source code must retain the above copyright notice,
  7   *    this list of conditions and the following disclaimer.
  8   * 2. Redistributions in binary form must reproduce the above copyright notice,
  9   *    this list of conditions and the following disclaimer in the documentation
 10   *    and/or other materials provided with the distribution.
 11   * 3. Neither the name of the copyright holder nor the names of its contributors
 12   *    may be used to endorse or promote products derived from this software without
 13   *    specific prior written permission.
 14   *
 15   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 16   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 17   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 18   * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 19   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 20   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 21   * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 22   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 23   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 24   * POSSIBILITY OF SUCH DAMAGE.
 25   *
 26   *//*
 27   * Copyright (C) 2008-2020 Advanced Micro Devices, Inc. All rights reserved.
 28   */
 29  
 30  #include "libm_amd.h"
 31  #include "libm_util_amd.h"
 32  #include "libm_special.h"
 33  
 34  
 35  double FN_PROTOTYPE_REF(nextafter)(double x, double y)
 36  {
 37  
 38  
 39      UT64 checkbits,checkbitsy;
 40      double dy = y;
 41      checkbits.f64=x;
 42  	checkbitsy.f64 = y;
 43  
 44  
 45  
 46  
 47      /* check if the number is nan */
 48      if(((checkbits.u64 & ~SIGNBIT_DP64) > EXPBITS_DP64 ))
 49      {
 50  #ifdef WINDOWS
 51  		return  __amd_handle_error("nextafter", __amd_nextafter, checkbits.u64 | QNAN_MASK_64 , _DOMAIN, AMD_F_NONE, EDOM, x, 0.0, 1);
 52  #else
 53  	    if (checkbits.u64 & QNAN_MASK_64)
 54  
 55  		return  __amd_handle_error("nextafter", __amd_nextafter, checkbits.u64 | QNAN_MASK_64 , _DOMAIN, AMD_F_NONE, EDOM, x, 0.0, 1);
 56  	    else
 57  		return  __amd_handle_error("nextafter", __amd_nextafter, checkbits.u64 | QNAN_MASK_64 , _DOMAIN, AMD_F_INVALID, EDOM, x, 0.0, 1);
 58  #endif
 59      }
 60  
 61  
 62      /* check if y is nan */
 63      if(((checkbitsy.u64 & ~SIGNBIT_DP64) > EXPBITS_DP64 ))
 64      {
 65  #ifdef WINDOWS
 66  		return  __amd_handle_error("nextafter", __amd_nextafter, checkbitsy.u64 | QNAN_MASK_64, _DOMAIN, AMD_F_NONE, EDOM, y, 0.0, 1);
 67  #else
 68  	    if (checkbitsy.u64 & QNAN_MASK_64)
 69  		return  __amd_handle_error("nextafter", __amd_nextafter, checkbitsy.u64 | QNAN_MASK_64, _DOMAIN, AMD_F_NONE, EDOM, y, 0.0, 1);
 70  	    else
 71  		return  __amd_handle_error("nextafter", __amd_nextafter, checkbits.u64 | QNAN_MASK_64 , _DOMAIN, AMD_F_INVALID, EDOM, x, 0.0, 1);
 72  #endif
 73      }
 74  	
 75  	
 76  	/* if x == y return y in the type of x */
 77      if( x == dy )
 78      {
 79          return dy;
 80      }
 81  
 82      if( x == 0.0)
 83      {
 84          checkbits.u64 = 1;
 85          if( dy > 0.0 )
 86               return checkbits.f64;
 87          else
 88              return -checkbits.f64;
 89      }
 90  
 91  
 92      /* compute the next heigher or lower value */
 93  
 94      if(((x>0.0) ^ (dy>x)) == 0)
 95      {
 96          checkbits.u64++;
 97      }
 98      else
 99      {
100          checkbits.u64--;
101      }
102  
103      /* check if the result is nan or inf */
104      if(((checkbits.u64 & ~SIGNBIT_DP64) >= EXPBITS_DP64 ))
105      {
106  		return  __amd_handle_error("nextafter", __amd_nextafter, checkbits.u64 | QNAN_MASK_64, _DOMAIN, AMD_F_NONE, EDOM, x, 0.0, 1);
107      }
108  
109      return checkbits.f64;
110  }
111