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#include "bid_trans.h"

static BID_UINT128 BID128_DEC_PI =
  { BID128_LH_INIT( 0xbabe5564e6f39f8full, 0x2ffe9ae4795796a7ull ) };
static BID_UINT128 BID128_DEC_PI12 =
  { BID128_LH_INIT( 0xdd5f2ab27379cfc7ull, 0x2ffe4d723cabcb53ull ) };
static BID_UINT128 BID128_DEC_PI14 =
  { BID128_LH_INIT( 0xeeaf955939bce7e4ull, 0x2ffe26b91e55e5a9ull ) };
static BID_UINT128 BID128_DEC_PI34 =
  { BID128_LH_INIT( 0xCC0EC00BAD36B7ABull, 0x2ffe742B5B01B0FDull ) };
static BID_UINT128 BID128_10POW36 =
  { BID128_LH_INIT( 0x0000000000000001ull, 0x3088000000000000ull ) };
static BID_UINT128 BID128_10POW_M36 =
  { BID128_LH_INIT( 0x0000000000000001ull, 0x2ff8000000000000ull ) };


BID128_FUNCTION_ARG2 (bid128_atan2, x, y)

BID_UINT128 CX, CY, z, zabs, res;
BID_UINT64  valid_y, sign_x, sign_y, sign_z;
int exponent_x, exponent_y, cmp_res;
_IDEC_flags save_flags;
BID_F128_TYPE rq, zq;

valid_y = unpack_BID128_value_BLE (&sign_y, &exponent_y, &CY, y);

  // 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
      (y.w[BID_HIGH_128W] & 0x7e00000000000000ull) == 0x7e00000000000000ull)
    __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) {
  // check if y is Inf. 
  if (((y.w[BID_HIGH_128W] & 0x7c00000000000000ull) == 0x7800000000000000ull))
    // return NaN 
  {
	  if(sign_y) {
		  res.w[BID_HIGH_128W] = sign_x ^ BID128_DEC_PI34.w[BID_HIGH_128W];
		  res.w[BID_LOW_128W] = BID128_DEC_PI34.w[BID_LOW_128W];
	  }
	  else {
		  res.w[BID_HIGH_128W] = sign_x ^ BID128_DEC_PI14.w[BID_HIGH_128W];
		  res.w[BID_LOW_128W] = BID128_DEC_PI14.w[BID_LOW_128W];
	  }
    BID_RETURN (res);
  }
  // y is NaN?
  if (((y.w[BID_HIGH_128W] & 0x7c00000000000000ull) != 0x7c00000000000000ull))
    // not NaN 
  {
    // return +/-pi/2
		  res.w[BID_HIGH_128W] = sign_x ^ BID128_DEC_PI12.w[BID_HIGH_128W];
		  res.w[BID_LOW_128W] = BID128_DEC_PI12.w[BID_LOW_128W];
		BID_RETURN (res);
  }
}
    // x is 0
if(valid_y) {
	if(sign_y)
	{
		res.w[BID_HIGH_128W] = sign_x^BID128_DEC_PI.w[BID_HIGH_128W];
		res.w[BID_LOW_128W] = BID128_DEC_PI.w[BID_LOW_128W];
	}
	else {
		res.w[BID_HIGH_128W] = sign_x;
		res.w[BID_LOW_128W] = 0;
	}
  BID_RETURN (res);
}
}

	if (!valid_y) {
  // y is Inf. or NaN

  // test if y is NaN
  if ((y.w[BID_HIGH_128W] & 0x7c00000000000000ull) == 0x7c00000000000000ull) {
#ifdef BID_SET_STATUS_FLAGS
    if ((y.w[BID_HIGH_128W] & 0x7e00000000000000ull) == 0x7e00000000000000ull)	// sNaN
      __set_status_flags (pfpsf, BID_INVALID_EXCEPTION);
#endif
    res.w[BID_HIGH_128W] = CY.w[BID_HIGH_128W] & QUIET_MASK64;
    res.w[BID_LOW_128W] = CY.w[BID_LOW_128W];
    BID_RETURN (res);
  }
  // y is Infinity?
  if ((y.w[BID_HIGH_128W] & 0x7800000000000000ull) == 0x7800000000000000ull) {
	  if(sign_y) {
		res.w[BID_HIGH_128W] = sign_x ^ BID128_DEC_PI.w[BID_HIGH_128W];
		res.w[BID_LOW_128W] = BID128_DEC_PI.w[BID_LOW_128W];
	  }
	  else {
		res.w[BID_HIGH_128W] = sign_x;
		res.w[BID_LOW_128W] = 0;
	  }
    BID_RETURN (res);
  }
  // y is 0
  if(!(CX.w[BID_HIGH_128W]|CX.w[BID_LOW_128W]))
  {
	if(sign_y)
	{
		res.w[BID_HIGH_128W] = sign_x^BID128_DEC_PI.w[BID_HIGH_128W];
		res.w[BID_LOW_128W] = BID128_DEC_PI.w[BID_LOW_128W];
	}
	else {
		res.w[BID_HIGH_128W] = sign_x;
		res.w[BID_LOW_128W] = 0;
	}
  }
  else {
	  // x finite, return +/-pi/2
		res.w[BID_HIGH_128W] = sign_x^BID128_DEC_PI12.w[BID_HIGH_128W];
		res.w[BID_LOW_128W] = BID128_DEC_PI12.w[BID_LOW_128W];
  }
  BID_RETURN (res);
}

	save_flags = *pfpsf;

    BIDECIMAL_CALL2 (bid128_div, z, x, y);
	zabs.w[BID_HIGH_128W] = z.w[BID_HIGH_128W] & 0x7fffffffffffffffull;
	zabs.w[BID_LOW_128W] = z.w[BID_LOW_128W];

	*pfpsf = save_flags;    // avoided incorrect OF/UF

    BIDECIMAL_CALL2_NORND (bid128_quiet_greater, 
            cmp_res, zabs, BID128_10POW36);
	if(cmp_res) {
		// |x/y|>10^36
		res.w[BID_HIGH_128W] = sign_x ^ BID128_DEC_PI12.w[BID_HIGH_128W];
		res.w[BID_LOW_128W] = BID128_DEC_PI12.w[BID_LOW_128W];
		BID_RETURN (res);
	}
    BIDECIMAL_CALL2_NORND (bid128_quiet_less, 
            cmp_res, zabs, BID128_10POW_M36);
	if(cmp_res) {
		// |x/y|<10^(-36)
		if(sign_y) {
			res.w[BID_HIGH_128W] = sign_x ^ BID128_DEC_PI.w[BID_HIGH_128W];
			res.w[BID_LOW_128W] = BID128_DEC_PI.w[BID_LOW_128W];
		}
		else {
			// Here could set UF correctly based on flags set in bid128_div
			res.w[BID_HIGH_128W] = z.w[BID_HIGH_128W];
			res.w[BID_LOW_128W] = z.w[BID_LOW_128W];
		}
		BID_RETURN (res);
	}

	BIDECIMAL_CALL1 (bid128_to_binary128, zq, zabs);
	__bid_f128_atan(rq, zq);
    BIDECIMAL_CALL1 (binary128_to_bid128, res, rq);

	if(sign_y) {
		BIDECIMAL_CALL2 (bid128_sub, res, BID128_DEC_PI, res);
	}

    res.w[BID_HIGH_128W] |= sign_x;

	BID_RETURN (res);
}
