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#define BID_FUNCTION_SETS_BINARY_FLAGS
#define BID_128RES
#include "bid_internal.h"

BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE(int, bid128_ilogb, x)

  BID_UINT128 CX;
  BID_UINT64 sign_x;
  BID_SINT64 D;
  int_float f64, fx;
  int exponent_x, bin_expon_cx, digits, res;

  BID_OPT_SAVE_BINARY_FLAGS()

   if (!unpack_BID128_value (&sign_x, &exponent_x, &CX, x)) {
#ifdef BID_SET_STATUS_FLAGS
      __set_status_flags (pfpsf, BID_INVALID_EXCEPTION);
#endif
	 res =  ((x.w[1] & 0x7c00000000000000ull) == 0x7800000000000000ull)? 0x7fffffff : 0x80000000;
     BID_RETURN_VAL (res);
  }
  // find number of digits in coefficient
  // 2^64
  f64.i = 0x5f800000;
  // fx ~ CX
  fx.d = (float) CX.w[1] * f64.d + (float) CX.w[0];
  bin_expon_cx = ((fx.i >> 23) & 0xff) - 0x7f;
  digits = bid_estimate_decimal_digits[bin_expon_cx];
  // scale = 38-estimate_decimal_digits[bin_expon_cx];
  D = CX.w[1] - bid_power10_index_binexp_128[bin_expon_cx].w[1];
  if (D > 0 || (!D && CX.w[0] >= bid_power10_index_binexp_128[bin_expon_cx].w[0])) {
    digits++;
  }

  exponent_x = exponent_x - DECIMAL_EXPONENT_BIAS_128 - 1 + digits;

  BID_RETURN_VAL (exponent_x);

}
