sqrtf.c

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MIT License
-----------
 
Copyright (c) 2002-2019 Advanced Micro Devices, Inc.
 
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#include "libm.h"
#include "libm_util.h"
 
#if USE_SOFTWARE_SQRT
#define USE_SQRTF_AMD_INLINE
#endif
#define USE_NANF_WITH_FLAGS
#define USE_HANDLE_ERRORF
#include "libm_inlines.h"
#if USE_SOFTWARE_SQRT
#undef USE_SQRTF_AMD_INLINE
#endif
#undef USE_NANF_WITH_FLAGS
#undef USE_HANDLE_ERRORF
 
#include "libm_errno.h"
 
// Disable "C4163: not available as intrinsic function" warning that older
// compilers may issue here.
#pragma warning(disable:4163)
#pragma function(sqrtf)
 
 
float sqrtf(float x)
{
#if USE_SOFTWARE_SQRT
  return sqrtf_amd_inline(x);
#else
  float r;
  unsigned int ux;
  GET_BITS_SP32(x, ux);
  /* Check for special cases for Microsoft error handling */
  if ((ux & PINFBITPATT_SP32) == PINFBITPATT_SP32)
    {
      /* x is infinity, or NaN */
      if (ux & MANTBITS_SP32)
        {
          /* NaN  of some sort */
          /* If it's a signaling NaN, convert to QNaN */
            return _handle_errorf("sqrtf", OP_SQRT, ux|0x00400000, _DOMAIN, 0,
                               EDOM, x, 0.0F, 1);
        }
      else
        {
          /* +/-infinity  */
          if (ux & SIGNBIT_SP32)
            {
              /* - infinity */
                return _handle_errorf("sqrtf", OP_SQRT, INDEFBITPATT_SP32, 
                            _DOMAIN, AMD_F_INVALID, EDOM, x, 0.0F, 1);
            }
          /* positive infinite is not a problem */
        }
    }
  if ((ux & SIGNBIT_SP32)&&(ux & ~SIGNBIT_SP32))  /* if x < zero */
    {
        return _handle_errorf("sqrtf", OP_SQRT, INDEFBITPATT_SP32, 
                    _DOMAIN, AMD_F_INVALID, EDOM, x, 0.0F, 1);
    }
 
      /* VC++ intrinsic call */
      _mm_store_ss(&r, _mm_sqrt_ss(_mm_load_ss(&x)));
  return r;
#endif
}