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  
 28  #include "libm_amd.h"
 29  #include "libm_util_amd.h"
 30  #include "libm_special.h"
 31  
 32  #ifdef WINDOWS
 33  /*In windows llong long int is 64 bit and long int is 32 bit.
 34    In Linux long long int and long int both are of size 64 bit*/
 35  long long int FN_PROTOTYPE_REF(llroundf)(float f)
 36  {
 37      UT32 u32d;
 38      UT32 u32Temp,u32result;
 39      int intexp, shift;
 40      U32 sign;
 41      long long int  result;
 42  
 43      u32d.f32 = u32Temp.f32 = f;
 44      if ((u32d.u32 & 0X7F800000) == 0x7F800000)
 45      {
 46          /*else the number is infinity*/
 47  		//Got to raise range or domain error
 48          {
 49  			__amd_handle_errorf("llroundf", __amd_lround, SIGNBIT_SP32, _DOMAIN, AMD_F_NONE, EDOM, f, 0.0, 1);
 50  			return SIGNBIT_DP64; /*GCC returns this when the number is out of range*/
 51          }
 52  
 53      }
 54  
 55      u32Temp.u32 &= 0x7FFFFFFF;
 56      intexp = (u32d.u32 & 0x7F800000) >> 23;
 57      sign = u32d.u32 & 0x80000000;
 58      intexp -= 0x7F;
 59  
 60  
 61      /* 1.0 x 2^-1 is the smallest number which can be rounded to 1 */
 62      if (intexp < -1)
 63          return (0);
 64  
 65  
 66      /* 1.0 x 2^31 (or 2^63) is already too large */
 67      if (intexp >= 63)
 68      {
 69          result = 0x8000000000000000;
 70  		__amd_handle_errorf("llroundf", __amd_lround, SIGNBIT_SP32, _DOMAIN, AMD_F_NONE, EDOM, f, 0.0, 1);
 71          return result;
 72      }
 73  
 74      u32result.f32 = u32Temp.f32;
 75  
 76      /* >= 2^52 is already an exact integer */
 77      if (intexp < 23)
 78      {
 79          /* add 0.5, extraction below will truncate */
 80          u32result.f32 = u32Temp.f32 + 0.5F;
 81      }
 82  
 83      intexp = (u32result.u32 & 0x7f800000) >> 23;
 84      intexp -= 0x7f;
 85      u32result.u32 &= 0x7fffff;
 86      u32result.u32 |= 0x00800000;
 87  
 88      result = u32result.u32;
 89  
 90      /*Since float is only 32 bit for higher accuracy we shift the result by 32 bits
 91       * In the next step we shift an extra 32 bits in the reverse direction based
 92       * on the value of intexp*/
 93      result = result << 32;
 94      shift = intexp - 55; /*55= 23 +32*/
 95  
 96  
 97  	if(shift < 0)
 98  		result = result >> (-shift);
 99  	if(shift > 0)
100          result = result << (shift);
101  
102      if (sign)
103          result = -result;
104      return result;
105  
106  }
107  
108  #else //WINDOWS
109  /*llroundf is equivalent to the linux implementation of 
110    lroundf. Both long int and long long int are of the same size*/
111  long long int FN_PROTOTYPE_REF(llroundf)(float f)
112  {
113      long long int result;
114      result = FN_PROTOTYPE(lroundf)(f);
115      return result;
116  
117  }
118  
119  #endif
120