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_errno_amd.h"
31  #include "libm_special.h"
32  
33  
34  float FN_PROTOTYPE_REF(nearbyintf)(float x)
35  {
36      /* Check for input range */
37  	unsigned int mxscr_stat;
38      UT32 checkbits,sign,val_2p23;
39      checkbits.f32=x;
40  
41      /* Clear the sign bit and check if the value can be rounded(i.e check if exponent less than 23) */
42      if( (checkbits.u32 & 0x7FFFFFFF) > 0x4B000000)
43      {
44        /* take care of nan or inf */
45  	if(	(checkbits.u32 & EXPBITS_SP32) == EXPBITS_SP32)
46  	{
47          if((checkbits.u32 & MANTBITS_SP32) == 0x0)
48          {
49              // x is Inf
50  #ifdef WINDOWS
51              return  __amd_handle_errorf("nearbyintf", __amd_nearbyint, checkbits.u32, _DOMAIN, AMD_F_INVALID, EDOM, x, 0.0, 1);
52  #else
53              return  __amd_handle_errorf("nearbyintf", __amd_nearbyint, checkbits.u32, _DOMAIN, AMD_F_NONE, EDOM, x, 0.0, 1);
54  #endif
55  		}
56  		else
57  		{
58  			// x is NaN
59  #ifdef WINDOWS
60  			return  __amd_handle_errorf("nearbyintf", __amd_nearbyint, checkbits.u32 | QNAN_MASK_32 , _DOMAIN, AMD_F_NONE, EDOM, x, 0.0, 1);
61  #else
62  			if (checkbits.u32 & QNAN_MASK_32)
63  			return  __amd_handle_errorf("nearbyintf", __amd_nearbyint, checkbits.u32 | QNAN_MASK_32 , _DOMAIN, AMD_F_NONE, EDOM, x, 0.0, 1);
64  			else
65  			return  __amd_handle_errorf("nearbyintf", __amd_nearbyint, checkbits.u32 | QNAN_MASK_32 , _DOMAIN, AMD_F_INVALID, EDOM, x, 0.0, 1);
66  #endif
67  		}
68  	}
69  	else
70  		return x;
71      }
72  
73      sign.u32 =  checkbits.u32 & 0x80000000;   
74      val_2p23.u32 = sign.u32 | 0x4B000000;
75  	 
76  	mxscr_stat = _mm_getcsr();
77  	_mm_setcsr(mxscr_stat | 0x00000800);
78      val_2p23.f32 = (x + val_2p23.f32) - val_2p23.f32;
79  	mxscr_stat = mxscr_stat & 0xffffffc0; // clear the exceptions
80  	_mm_setcsr(mxscr_stat);
81      /*This extra line is to take care of denormals and various rounding modes*/
82      val_2p23.u32 = ((val_2p23.u32 << 1) >> 1) | sign.u32;
83  
84      return (val_2p23.f32);   
85  }
86  
87