hypotf.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"
 
#ifdef USE_SOFTWARE_SQRT
#define USE_SQRTF_AMD_INLINE
#endif
#define USE_INFINITYF_WITH_FLAGS
#define USE_HANDLE_ERRORF
#include "libm_inlines.h"
#ifdef USE_SOFTWARE_SQRT
#undef USE_SQRTF_AMD_INLINE
#endif
#undef USE_INFINITYF_WITH_FLAGS
#undef USE_HANDLE_ERRORF
 
#include "libm_errno.h"
 
 
float FN_PROTOTYPE(_hypotf)(float x, float y)
{
  /* Returns sqrt(x*x + y*y) with no overflow or underflow unless
     the result warrants it */
 
    /* Do intermediate computations in double precision
       and use sqrt instruction from chip if available. */
    double dx = x, dy = y, dr, retval;
 
    /* The largest finite float, stored as a double */
    const double large = 3.40282346638528859812e+38; /* 0x47efffffe0000000 */
 
 
  unsigned long long ux, uy, avx, avy;
 
  GET_BITS_DP64(x, avx);
  avx &= ~SIGNBIT_DP64;
  GET_BITS_DP64(y, avy);
  avy &= ~SIGNBIT_DP64;
  ux = (avx >> EXPSHIFTBITS_DP64);
  uy = (avy >> EXPSHIFTBITS_DP64);
 
  if (ux == BIASEDEMAX_DP64 + 1 || uy == BIASEDEMAX_DP64 + 1)
    {
      retval = x*x + y*y;
      /* One or both of the arguments are NaN or infinity. The
         result will also be NaN or infinity. */
      if (((ux == BIASEDEMAX_DP64 + 1) && !(avx & MANTBITS_DP64)) ||
          ((uy == BIASEDEMAX_DP64 + 1) && !(avy & MANTBITS_DP64)))
        /* x or y is infinity. ISO C99 defines that we must
           return +infinity, even if the other argument is NaN.
           Note that the computation of x*x + y*y above will already
           have raised invalid if either x or y is a signalling NaN. */
        return infinityf_with_flags(0);
      else
        /* One or both of x or y is NaN, and neither is infinity.
           Raise invalid if it's a signalling NaN */
        return (float)retval;
    }
 
    dr = (dx*dx + dy*dy);
 
#if USE_SOFTWARE_SQRT
    retval = sqrtf_amd_inline(r);
#else
  /* VC++ intrinsic call */
  _mm_store_sd(&retval, _mm_sqrt_sd(_mm_setzero_pd(), _mm_load_sd(&dr)));
#endif
 
    if (retval > large)
      return _handle_errorf("_hypotf", OP_HYPOT, PINFBITPATT_SP32, _OVERFLOW,
                           AMD_F_OVERFLOW | AMD_F_INEXACT, ERANGE, x, y, 2);
    else
      return (float)retval;
}