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  #define BID_128RES
  #include "bid_internal.h"
  
  
  BID128_FUNCTION_ARG128_CUSTOMARGTYPE2_PLAIN(bid128_frexp, x, int*, exp)
  /* 
    If x is not a floating-point number, the results are unspecified (this
    implementation returns x and *exp = 0). Otherwise, the frexp function 
    returns the value res, such that res has a magnitude in the interval 
    [1/10, 1) or zero, and x = res*2^*exp. If x is zero, both parts of the 
    result are zero
    frexp does not raise any exceptions
   */
  
    BID_UINT128 res;
    BID_UINT128 sig_x; 
    unsigned int exp_x;
    BID_UI64DOUBLE tmp;
    int x_nr_bits, q;
  
    if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) {
      // if NaN or infinity
      *exp = 0;
      res = x;
      // the binary frexp quitetizes SNaNs, so do the same
      if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN 
      //   // set invalid flag
      //   *pfpsf |= BID_INVALID_EXCEPTION;
        // return quiet (x)
        res.w[1] = x.w[1] & 0xfdffffffffffffffull;
      }
      BID_RETURN (res); 
    } else {
      // x is 0, non-canonical, normal, or subnormal
      // check for non-canonical values with 114 bit-significands; can be zero too
      if ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull) {
        *exp = 0;
        exp_x = (x.w[1] & MASK_EXP2) >> 47; // biased
        res.w[1] = (x.w[1] & 0x8000000000000000ull) | ((BID_UINT64)exp_x << 49); 
            // zero of same sign
        res.w[0] = 0x0000000000000000ull;
        BID_RETURN (res);
      }
      // unpack x
      exp_x = (x.w[1] & MASK_EXP) >> 49; // biased
      sig_x.w[1] = x.w[1] & MASK_COEFF;   
      sig_x.w[0] = x.w[0]; 
      // check for non-canonical values or zero
      if ((sig_x.w[1] > 0x0001ed09bead87c0ull)
          || (sig_x.w[1] == 0x0001ed09bead87c0ull
              && (sig_x.w[0] > 0x378d8e63ffffffffull)) ||
            ((sig_x.w[1] == 0x0ull) && (sig_x.w[0] == 0x0ull))) {
        *exp = 0;
        res.w[1] = (x.w[1] & 0x8000000000000000ull) | ((BID_UINT64)exp_x << 49); 
            // zero of same sign
        res.w[0] = 0x0000000000000000ull;
        BID_RETURN (res);
      } else {
        ; // continue, x is neither zero nor non-canonical 
      }
      // x is normal or subnormal, with exp_x=biased exponent & sig_x=coefficient
      // determine the number of decimal digits in sig_x, which fits in 113 bits
      // q = nr. of decimal digits in sig_x (1 <= q <= 34) 
      //  determine first the nr. of bits in sig_x
      if (sig_x.w[1] == 0) {
        if (sig_x.w[0] >= 0x0020000000000000ull) { // z >= 2^53
          // split the 64-bit value in two 32-bit halves to avoid rounding errors
          if (sig_x.w[0] >= 0x0000000100000000ull) { // z >= 2^32
            tmp.d = (double) (sig_x.w[0] >> 32); // exact conversion
            x_nr_bits =
              32 + ((((unsigned int) (tmp.ui64 >> 52)) & 0x7ff) - 0x3ff);
          } else { // z < 2^32
            tmp.d = (double) sig_x.w[0]; // exact conversion
            x_nr_bits =
              ((((unsigned int) (tmp.ui64 >> 52)) & 0x7ff) - 0x3ff);
          }
        } else { // if z < 2^53
          tmp.d = (double) sig_x.w[0]; // exact conversion
          x_nr_bits = ((((unsigned int) (tmp.ui64 >> 52)) & 0x7ff) - 0x3ff);
        }
      } else { // sig_x.w[1] != 0 => nr. bits = 65 + nr_bits (sig_x.w[1])
        tmp.d = (double) sig_x.w[1]; // exact conversion
        x_nr_bits = 64 + ((((unsigned int) (tmp.ui64 >> 52)) & 0x7ff) - 0x3ff);
      }
      q = bid_nr_digits[x_nr_bits].digits;
      if (q == 0) {
        q = bid_nr_digits[x_nr_bits].digits1;
        if (sig_x.w[1] > bid_nr_digits[x_nr_bits].threshold_hi ||
            (sig_x.w[1] == bid_nr_digits[x_nr_bits].threshold_hi &&
             sig_x.w[0] >= bid_nr_digits[x_nr_bits].threshold_lo))
          q++;
      }
      // Do not add trailing zeros if q < 34; leave sig_x with q digits
      *exp = exp_x - 6176 + q;
      // assemble the result; sig_x < 2^113 so it fits in 113 bits
      res.w[1] = (x.w[1] & 0x8001ffffffffffffull) | ((-q + 6176ull) << 49); 
      res.w[0] = x.w[0]; 
        // replace exponent
      BID_RETURN (res);
    }
  }
  