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* 'double' and 'mp_int' types.
*
* Copyright (c) 2005 by Kevin B. Kenny. All rights reserved.
*
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
* RCS: @(#) $Id: tclStrToD.c,v 1.44 2010/05/03 14:36:41 nijtmans Exp $
*
*----------------------------------------------------------------------
*/
#include "tclInt.h"
#include "tommath.h"
#include <math.h>
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* 'double' and 'mp_int' types.
*
* Copyright (c) 2005 by Kevin B. Kenny. All rights reserved.
*
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
* RCS: @(#) $Id: tclStrToD.c,v 1.45 2010/05/17 21:51:21 nijtmans Exp $
*
*----------------------------------------------------------------------
*/
#include "tclInt.h"
#include "tommath.h"
#include <math.h>
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* represented exactly in a 'double'. */
static int log10_DIGIT_MAX; /* The number of decimal digits that fit in an
* mp_digit. */
static int log2FLT_RADIX; /* Logarithm of the floating point radix. */
static int mantBits; /* Number of bits in a double's significand */
static mp_int pow5[9]; /* Table of powers of 5**(2**n), up to
* 5**256 */
static int maxDigits; /* The maximum number of digits to the left of
* the decimal point of a double. */
static int minDigits; /* The maximum number of digits to the right
* of the decimal point in a double. */
static int mantDIGIT; /* Number of mp_digit's needed to hold the
* significand of a double. */
static const double pow_10_2_n[] = { /* Inexact higher powers of ten. */
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* represented exactly in a 'double'. */
static int log10_DIGIT_MAX; /* The number of decimal digits that fit in an
* mp_digit. */
static int log2FLT_RADIX; /* Logarithm of the floating point radix. */
static int mantBits; /* Number of bits in a double's significand */
static mp_int pow5[9]; /* Table of powers of 5**(2**n), up to
* 5**256 */
static double tiny = 0.0; /* The smallest representable double */
static int maxDigits; /* The maximum number of digits to the left of
* the decimal point of a double. */
static int minDigits; /* The maximum number of digits to the right
* of the decimal point in a double. */
static int mantDIGIT; /* Number of mp_digit's needed to hold the
* significand of a double. */
static const double pow_10_2_n[] = { /* Inexact higher powers of ten. */
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retval = BignumToBiasedFrExp(significand, &machexp);
retval = Pow10TimesFrExp(exponent, retval, &machexp);
if (machexp > DBL_MAX_EXP*log2FLT_RADIX) {
retval = HUGE_VAL;
goto returnValue;
}
retval = SafeLdExp(retval, machexp);
if (retval <= 0.0) {
retval = SafeLdExp(1.0, DBL_MIN_EXP * log2FLT_RADIX - mantBits);
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retval = BignumToBiasedFrExp(significand, &machexp);
retval = Pow10TimesFrExp(exponent, retval, &machexp);
if (machexp > DBL_MAX_EXP*log2FLT_RADIX) {
retval = HUGE_VAL;
goto returnValue;
}
retval = SafeLdExp(retval, machexp);
if (tiny == 0.0) {
tiny = SafeLdExp(1.0, DBL_MIN_EXP * log2FLT_RADIX - mantBits);
}
if (retval < tiny) {
retval = tiny;
}
/*
* Refine the result twice. (The second refinement should be necessary
* only if the best approximation is a power of 2 minus 1/2 ulp).
*/
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