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#include "bid_trans.h"

BID_F128_CONST_DEF( c_half,    3ffe000000000000, 0000000000000000); // 0.5

BID128_FUNCTION_ARG1 (bid128_atanh, x)

BID_UINT128 CX, CY, xn, one, one_m_x, one_p_x, res, tmp, coeff_res, y;
BID_UINT64  sign_x;
int exponent_x, exponent_y, cmp_res, exponent_res;
BID_F128_TYPE rq, xq, yq;

  // unpack arguments, check for NaN or Infinity
	if (!unpack_BID128_value_BLE (&sign_x, &exponent_x, &CX, x)) {
    // test if x is NaN
if ((x.w[BID_HIGH_128W] & 0x7c00000000000000ull) == 0x7c00000000000000ull) {
#ifdef BID_SET_STATUS_FLAGS
  if ((x.w[BID_HIGH_128W] & 0x7e00000000000000ull) == 0x7e00000000000000ull)	// sNaN
    __set_status_flags (pfpsf, BID_INVALID_EXCEPTION);
#endif
	res.w[BID_HIGH_128W] = (CX.w[BID_HIGH_128W]) & QUIET_MASK64;
	res.w[BID_LOW_128W] = CX.w[BID_LOW_128W];
	BID_RETURN (res);
}
    // x is Infinity?
if ((x.w[BID_HIGH_128W] & 0x7800000000000000ull) == 0x7800000000000000ull) {
#ifdef BID_SET_STATUS_FLAGS
    __set_status_flags (pfpsf, BID_INVALID_EXCEPTION);
#endif
	  res.w[BID_HIGH_128W] = 0x7c00000000000000ull;
	  res.w[BID_LOW_128W] = 0;
    BID_RETURN (res);
  }
    // x is 0
	 res.w[BID_HIGH_128W] = sign_x | CX.w[BID_HIGH_128W];
	 res.w[BID_LOW_128W] = CX.w[BID_LOW_128W];
     BID_RETURN (res);
}

	
	if(exponent_x <= DECIMAL_EXPONENT_BIAS_128 - 51)
	{
		res.w[BID_HIGH_128W] = x.w[BID_HIGH_128W];
		res.w[BID_LOW_128W] = x.w[BID_LOW_128W];
		BID_RETURN (res);
	}

	// |x| 
	xn.w[BID_HIGH_128W] = x.w[BID_HIGH_128W] & 0x7fffffffffffffffull;
	xn.w[BID_LOW_128W] = x.w[BID_LOW_128W];

	// 1.0
	one.w[BID_HIGH_128W] = 0x3040000000000000ull;    one.w[BID_LOW_128W] = 1;

	// 1 - |x|
	BIDECIMAL_CALL2 (bid128_sub, one_m_x, one, xn);

	if(one_m_x.w[BID_HIGH_128W] & 0x8000000000000000ull)
	{
		// |x|>1
#ifdef BID_SET_STATUS_FLAGS
    __set_status_flags (pfpsf, BID_INVALID_EXCEPTION);
#endif
	  res.w[BID_HIGH_128W] = 0x7c00000000000000ull;
	  res.w[BID_LOW_128W] = 0;
      BID_RETURN (res);
  }

  if((!one_m_x.w[BID_LOW_128W]) && !(one_m_x.w[BID_HIGH_128W]<<15))
  {
	  // |x|==1
#ifdef BID_SET_STATUS_FLAGS
    __set_status_flags (pfpsf, BID_ZERO_DIVIDE_EXCEPTION);
#endif
	  res.w[BID_HIGH_128W] = sign_x | 0x7800000000000000ull;
	  res.w[BID_LOW_128W] = 0;
      BID_RETURN (res);
  }

	// (2*|x|)/(1-|x|)
	BIDECIMAL_CALL2 (bid128_div, tmp, xn, one_m_x);
	BIDECIMAL_CALL2 (bid128_add, y, tmp, tmp);

	BIDECIMAL_CALL1 (bid128_to_binary128, xq, y);
	__bid_f128_log1p(rq, xq);        
	__bid_f128_mul(rq, rq, c_half.v);
    BIDECIMAL_CALL1 (binary128_to_bid128, res, rq);

	res.w[BID_HIGH_128W] ^= sign_x;

	BID_RETURN (res);
}


