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/****************************************************************

  The author of this software (_dtoa, strtod) is David M. Gay.

  Please send bug reports to

	David M. Gay

	Bell Laboratories, Room 2C-463

	600 Mountain Avenue

	Murray Hill, NJ 07974-2070

	U.S.A.

	dmg@research.bell-labs.com

 */

#include <stdlib.h>

#include <string.h>

#define _RESEARCH_SOURCE

#include <errno.h>

#include <float.h>

#include <math.h>

#define CONST const

/*

 * #define IEEE_8087 for IEEE-arithmetic machines where the least

 *	significant byte has the lowest address.

 * #define IEEE_MC68k for IEEE-arithmetic machines where the most

 *	significant byte has the lowest address.

 * #define Sudden_Underflow for IEEE-format machines without gradual

 *	underflow (i.e., that flush to zero on underflow).

 * #define IBM for IBM mainframe-style floating-point arithmetic.

 * #define VAX for VAX-style floating-point arithmetic.

 * #define Unsigned_Shifts if >> does treats its left operand as unsigned.

 * #define No_leftright to omit left-right logic in fast floating-point

 *	computation of dtoa.

 * #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3.

 * #define RND_PRODQUOT to use rnd_prod and rnd_quot (assembly routines

 *	that use extended-precision instructions to compute rounded

 *	products and quotients) with IBM.

 * #define ROUND_BIASED for IEEE-format with biased rounding.

 * #define Inaccurate_Divide for IEEE-format with correctly rounded

 *	products but inaccurate quotients, e.g., for Intel i860.

 * #define Just_16 to store 16 bits per 32-bit long when doing high-precision

 *	integer arithmetic.  Whether this speeds things up or slows things

 *	down depends on the machine and the number being converted.

 */

#if defined(IEEE_8087) + defined(IEEE_MC68k) + defined(VAX) + defined(IBM) != 1

Exactly one of IEEE_8087, IEEE_MC68k, VAX, or IBM should be defined.

#endif

typedef union {

	double d;

	unsigned long ul[2];

} Dul;

#ifdef IEEE_8087

#define word0(x) ((x).ul[1])

#define word1(x) ((x).ul[0])

#else

#define word0(x) ((x).ul[0])

#define word1(x) ((x).ul[1])

#endif

#ifdef Unsigned_Shifts

#define Sign_Extend(a,b) if (b < 0) a |= 0xffff0000;

#else

#define Sign_Extend(a,b) /*no-op*/

#endif

/* The following definition of Storeinc is appropriate for MIPS processors.

 * An alternative that might be better on some machines is

 * #define Storeinc(a,b,c) (*a++ = b << 16 | c & 0xffff)

 */

#if defined(IEEE_8087) + defined(VAX)

#define Storeinc(a,b,c) (((unsigned short *)a)[1] = (unsigned short)b, \

((unsigned short *)a)[0] = (unsigned short)c, a++)

#else

#define Storeinc(a,b,c) (((unsigned short *)a)[0] = (unsigned short)b, \

((unsigned short *)a)[1] = (unsigned short)c, a++)

#endif

/* #define P DBL_MANT_DIG */

/* Ten_pmax = floor(P*log(2)/log(5)) */

/* Bletch = (highest power of 2 < DBL_MAX_10_EXP) / 16 */

/* Quick_max = floor((P-1)*log(FLT_RADIX)/log(10) - 1) */

/* Int_max = floor(P*log(FLT_RADIX)/log(10) - 1) */

#if defined(IEEE_8087) + defined(IEEE_MC68k)

#define Exp_shift  20

#define Exp_shift1 20

#define Exp_msk1    0x100000

#define Exp_msk11   0x100000

#define Exp_mask  0x7ff00000

#define P 53

#define Bias 1023

#define IEEE_Arith

#define Emin (-1022)

#define Exp_1  0x3ff00000

#define Exp_11 0x3ff00000

#define Ebits 11

#define Frac_mask  0xfffff

#define Frac_mask1 0xfffff

#define Ten_pmax 22

#define Bletch 0x10

#define Bndry_mask  0xfffff

#define Bndry_mask1 0xfffff

#define LSB 1

#define Sign_bit 0x80000000

#define Log2P 1

#define Tiny0 0

#define Tiny1 1

#define Quick_max 14

#define Int_max 14

#define Infinite(x) (word0(x) == 0x7ff00000) /* sufficient test for here */

#else

#undef  Sudden_Underflow

#define Sudden_Underflow

#ifdef IBM

#define Exp_shift  24

#define Exp_shift1 24

#define Exp_msk1   0x1000000

#define Exp_msk11  0x1000000

#define Exp_mask  0x7f000000

#define P 14

#define Bias 65

#define Exp_1  0x41000000

#define Exp_11 0x41000000

#define Ebits 8	/* exponent has 7 bits, but 8 is the right value in b2d */

#define Frac_mask  0xffffff

#define Frac_mask1 0xffffff

#define Bletch 4

#define Ten_pmax 22

#define Bndry_mask  0xefffff

#define Bndry_mask1 0xffffff

#define LSB 1

#define Sign_bit 0x80000000

#define Log2P 4

#define Tiny0 0x100000

#define Tiny1 0

#define Quick_max 14

#define Int_max 15

#else /* VAX */

#define Exp_shift  23

#define Exp_shift1 7

#define Exp_msk1    0x80

#define Exp_msk11   0x800000

#define Exp_mask  0x7f80

#define P 56

#define Bias 129

#define Exp_1  0x40800000

#define Exp_11 0x4080

#define Ebits 8

#define Frac_mask  0x7fffff

#define Frac_mask1 0xffff007f

#define Ten_pmax 24

#define Bletch 2

#define Bndry_mask  0xffff007f

#define Bndry_mask1 0xffff007f

#define LSB 0x10000

#define Sign_bit 0x8000

#define Log2P 1

#define Tiny0 0x80

#define Tiny1 0

#define Quick_max 15

#define Int_max 15

#endif

#endif

#ifndef IEEE_Arith

#define ROUND_BIASED

#endif

#define Big0 (Frac_mask1 | Exp_msk1*(DBL_MAX_EXP+Bias-1))

#define Big1 0xffffffff

#ifndef Just_16

/* When Pack_32 is not defined, we store 16 bits per 32-bit long.

 * This makes some inner loops simpler and sometimes saves work

 * during multiplications, but it often seems to make things slightly

 * slower.  Hence the default is now to store 32 bits per long.

 */

#ifndef Pack_32

#define Pack_32

#endif

#endif

#define Kmax 15

 struct

Bigint {

	struct Bigint *next;

	int k, maxwds, sign, wds;

	unsigned long x[1];

	};

 typedef struct Bigint Bigint;

/* This routines shouldn't be visible externally */

extern Bigint	*_Balloc(int);

extern void	_Bfree(Bigint *);

extern Bigint	*_multadd(Bigint *, int, int);

extern int	_hi0bits(unsigned long);

extern Bigint	*_mult(Bigint *, Bigint *);

extern Bigint	*_pow5mult(Bigint *, int);

extern Bigint	*_lshift(Bigint *, int);

extern int	_cmp(Bigint *, Bigint *);

extern Bigint	*_diff(Bigint *, Bigint *);

extern Bigint	*_d2b(double, int *, int *);

extern Bigint	*_i2b(int);

extern double	_tens[], _bigtens[], _tinytens[];

#ifdef IEEE_Arith

#define n_bigtens 5

#else

#ifdef IBM

#define n_bigtens 3

#else

#define n_bigtens 2

#endif

#endif

#define Balloc(x) _Balloc(x)

#define Bfree(x) _Bfree(x)

#define Bcopy(x,y) memcpy((char *)&x->sign, (char *)&y->sign, \

y->wds*sizeof(long) + 2*sizeof(int))

#define multadd(x,y,z) _multadd(x,y,z)

#define hi0bits(x) _hi0bits(x)

#define i2b(x) _i2b(x)

#define mult(x,y) _mult(x,y)

#define pow5mult(x,y) _pow5mult(x,y)

#define lshift(x,y) _lshift(x,y)

#define cmp(x,y) _cmp(x,y)

#define diff(x,y) _diff(x,y)

#define d2b(x,y,z) _d2b(x,y,z)

#define tens _tens

#define bigtens _bigtens

#define tinytens _tinytens