Tcl_WideUInt *wideRepPtr,	/* Representation of the partial number as a
				 * wide integer. */
    mp_int *bignumRepPtr,	/* Representation of the partial number as a
				 * bignum. */
    int bignumFlag)		/* Flag == 1 if the number overflowed previous
				 * to this digit. */
{
    int i, n;
    Tcl_WideUInt w;

    /*
     * Try wide multiplication first.
     */

    if (!bignumFlag) {
	w = *wideRepPtr;
	if (w == 0) {
	    /*
	     * There's no need to multiply if the multiplicand is zero.
	     */

	    *wideRepPtr = digit;
	    return 0;

	 */

	if ((mp_mul_d(bignumRepPtr, (mp_digit) pow10_wide[numZeros+1],
		bignumRepPtr) != MP_OKAY)
		|| (mp_add_d(bignumRepPtr, (mp_digit) digit, bignumRepPtr) != MP_OKAY))
	return 0;
    } else {
	mp_err err;
	/*
	 * More than single digit multiplication. Multiply by the appropriate
	 * small powers of 5, and then shift. Large strings of zeroes are
	 * eaten 256 at a time; this is less efficient than it could be, but
	 * seems implausible. We presume that MP_DIGIT_BIT is at least 27. The
	 * first multiplication, by up to 10**7, is done with a one-DIGIT
	 * multiply (this presumes that MP_DIGIT_BIT >= 24).
	 */

	n = numZeros + 1;
	err = mp_mul_d(bignumRepPtr, (mp_digit) pow10_wide[n&0x7], bignumRepPtr);
	for (i = 3; (err == MP_OKAY) && (i <= 7); ++i) {
	    if (n & (1 << i)) {
		err = mp_mul(bignumRepPtr, pow5+i, bignumRepPtr);
	    }
	}
	while ((err == MP_OKAY) && (n >= 256)) {
	    err = mp_mul(bignumRepPtr, pow5+8, bignumRepPtr);
	    n -= 256;

    double *dPtr,		/* INOUT: Number to adjust. */
    int k)			/* IN: floor(log10(d)) */
{
    int ieps;			/* Number of roundoff errors that have
				 * accumulated. */
    double d = *dPtr;		/* Number to adjust. */
    double ds;
    int i, j, j1;

    ieps = 2;

    if (k > 0) {
	/*
	 * The number must be reduced to bring it into range.
	 */

	ds = tens[k & 0xF];
	j = k >> 4;
	if (j & BLETCH) {
	    j &= (BLETCH-1);
	    d /= bigtens[N_BIGTENS - 1];
	    ieps++;
	}
	i = 0;
	for (; j != 0; j>>=1) {

    } else if ((j1 = -k) != 0) {
	/*
	 * The number must be increased to bring it into range.
	 */

	d *= tens[j1 & 0xF];
	i = 0;
	for (j = j1>>4; j; j>>=1) {
	    if (j & 1) {
		ieps++;
		d *= bigtens[i];
	    }
	    ++i;
	}
    }

static inline int
ShouldBankerRoundUpPowD(
    mp_int *b,			/* Numerator of the fraction. */
    int sd,			/* Denominator is 2**(sd*MP_DIGIT_BIT). */
    int isodd)			/* 1 if the digit is odd, 0 if even. */
{
    int i;
    static const mp_digit topbit = ((mp_digit)1) << (MP_DIGIT_BIT - 1);

    if (b->used < sd || (b->dp[sd-1] & topbit) == 0) {
	return 0;
    }
    if (b->dp[sd-1] != topbit) {
	return 1;
    }
    for (i = sd-2; i >= 0; --i) {
	if (b->dp[i] != 0) {
	    return 1;
	}
    }
    return isodd;
}


ShouldBankerRoundUpToNextPowD(
    mp_int *b,			/* Numerator of the fraction. */
    mp_int *m,			/* Numerator of the rounding tolerance. */
    int sd,			/* Common denominator is 2**(sd*MP_DIGIT_BIT). */
    int isodd,			/* 1 if the integer significand is odd. */
    mp_int *temp)		/* Work area for the calculation. */
{
    int i;

    /*
     * Compare B and S-m - which is the same as comparing B+m and S - which we
     * do by computing b+m and doing a bitwhack compare against
     * 2**(MP_DIGIT_BIT*sd)
     */

    if ((mp_add(b, m, temp) != MP_OKAY) || (temp->used <= sd)) {
	/* Too few digits to be > s */
	return 0;
    }
    if (temp->used > sd+1 || temp->dp[sd] > 1) {
				/* >= 2s */
	return 1;
    }
    for (i = sd-1; i >= 0; --i) {
				/* Check for ==s */
	if (temp->dp[i] != 0) {	/* > s */
	    return 1;
	}
    }
    return isodd;
}

				/* Buffer of digits to return. */
    char *s = retval;		/* Cursor in the return value. */
    mp_int b;			/* Numerator of the result. */
    mp_int S;			/* Denominator of the result. */
    mp_int dig;			/* Current digit of the result. */
    int digit;			/* Current digit of the result. */
    int g;			/* Size of the current digit ground. */
    int i, j;
    mp_err err;

    /*
     * b = bw * 2**b2 * 5**b5
     * S = 2**s2 * 5*s5
     */

	     * Extract the next group of digits.
	     */

	    if ((err != MP_OKAY) || (mp_div(&b, &S, &dig, &b) != MP_OKAY) || (dig.used > 1)) {
		Tcl_Panic("wrong digit!");
	    }
	    digit = (int)dig.dp[0];
	    for (j = g-1; j >= 0; --j) {
		int t = itens[j];

		*s++ = (char)(digit / t + '0');
		digit %= t;
	    }
	    i += g;

 *
 *----------------------------------------------------------------------
 */

void
TclFinalizeDoubleConversion(void)
{
    int i;

    Tcl_Free(pow10_wide);
    for (i=0; i<9; ++i) {
	mp_clear(pow5 + i);
    }
    for (i=0; i < 5; ++i) {
	mp_clear(pow5_13 + i);
    }
}

/*
 *----------------------------------------------------------------------
 *

 */

double
TclBignumToDouble(
    const void *big)		/* Integer to convert. */
{
    mp_int b;
    int bits, shift, i, lsb;
    double r;
    mp_err err;
    const mp_int *a = (const mp_int *)big;

    /*
     * We need a 'mantBits'-bit significand.  Determine what shift will
     * give us that.

     * Accumulate the result, one mp_digit at a time.
     */

    if (err != MP_OKAY) {
	return 0.0;
    }
    r = 0.0;
    for (i = b.used-1; i>=0; --i) {
	r = ldexp(r, MP_DIGIT_BIT) + (double)b.dp[i];
    }
    mp_clear(&b);

    /*
     * Scale the result to the correct number of bits.
     */

	r = -TclFloor(&b);
    } else {
	int bits = mp_count_bits(a);

	if (bits > DBL_MAX_EXP*log2FLT_RADIX) {
	    r = HUGE_VAL;
	} else {
	    int i, exact = 1, shift = mantBits - bits;

	    if (err != MP_OKAY) {
		/* just skip */
	    } else if (shift > 0) {
		err = mp_mul_2d(a, shift, &b);
	    } else if (shift < 0) {
		mp_int d;

	    }
	    if ((err == MP_OKAY) && !exact) {
		err = mp_add_d(&b, 1, &b);
	    }
	    if (err != MP_OKAY) {
		return 0.0;
	    }
	    for (i=b.used-1 ; i>=0 ; --i) {
		r = ldexp(r, MP_DIGIT_BIT) + (double)b.dp[i];
	    }
	    r = ldexp(r, bits - mantBits);
	}
    }
    mp_clear(&b);
    return r;

	r = -TclCeil(&b);
    } else {
	int bits = mp_count_bits(a);

	if (bits > DBL_MAX_EXP*log2FLT_RADIX) {
	    r = DBL_MAX;
	} else {
	    int i, shift = mantBits - bits;

	    if (shift > 0) {
		err = mp_mul_2d(a, shift, &b);
	    } else if (shift < 0) {
		err = mp_div_2d(a, -shift, &b, NULL);
	    } else {
		err = mp_copy(a, &b);
	    }
	    if (err != MP_OKAY) {
		return 0.0;
	    }
	    for (i=b.used-1 ; i>=0 ; --i) {
		r = ldexp(r, MP_DIGIT_BIT) + (double)b.dp[i];
	    }
	    r = ldexp(r, bits - mantBits);
	}
    }
    mp_clear(&b);
    return r;

BignumToBiasedFrExp(
    const mp_int *a,		/* Integer to convert. */
    int *machexp)		/* Power of two. */
{
    mp_int b;
    int bits;
    int shift;
    int i;
    double r;
    mp_err err = MP_OKAY;

    /*
     * Determine how many bits we need, and extract that many from the input.
     * Round to nearest unit in the last place.
     */

    /*
     * Accumulate the result, one mp_digit at a time.
     */

    r = 0.0;
    if (err == MP_OKAY) {
	for (i=b.used-1; i>=0; --i) {
	    r = ldexp(r, MP_DIGIT_BIT) + (double)b.dp[i];
	}
    }
    mp_clear(&b);

    /*
     * Return the result with the appropriate sign.

static double
Pow10TimesFrExp(
    int exponent,		/* Power of 10 to multiply by. */
    double fraction,		/* Significand of multiplicand. */
    int *machexp)		/* On input, exponent of multiplicand. On
				 * output, exponent of result. */
{
    int i, j;
    int expt = *machexp;
    double retval = fraction;

    if (exponent > 0) {
	/*
	 * Multiply by 10**exponent.
	 */

	retval = frexp(retval * pow10vals[exponent & 0xF], &j);
	expt += j;
	for (i=4; i<9; ++i) {
	    if (exponent & (1<<i)) {
		retval = frexp(retval * pow_10_2_n[i], &j);
		expt += j;
	    }
	}
    } else if (exponent < 0) {
	/*
	 * Divide by 10**-exponent.
	 */

	retval = frexp(retval / pow10vals[(-exponent) & 0xF], &j);
	expt += j;
	for (i=4; i<9; ++i) {
	    if ((-exponent) & (1<<i)) {
		retval = frexp(retval / pow_10_2_n[i], &j);
		expt += j;
	    }
	}
    }