/**************************************************************** * * The author of this software (_dtoa, strtod) is David M. Gay. * * Copyright (c) 1991 by AT&T. * * Permission to use, copy, modify, and distribute this software for any * purpose without fee is hereby granted, provided that this entire notice * is included in all copies of any software which is or includes a copy * or modification of this software and in all copies of the supporting * documentation for such software. * * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHOR NOR AT&T MAKES ANY * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. * ***************************************************************/ /* Please send bug reports to	David M. Gay	AT&T Bell Laboratories, Room 2C-463	600 Mountain Avenue	Murray Hill, NJ 07974-2070	U.S.A.	dmg@research.att.com or research!dmg */ /* Version by Howard Trickey: only IEEE, print modes needed for stdio */ #include <u.h>#include <libc.h>#define _RESEARCH_SOURCE#include <ape/float.h> /* * #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 Unsigned_Shifts if >> does treats its left operand as unsigned. * #define Sudden_Underflow 1 for IEEE-format machines without gradual *	underflow (i.e., that flush to zero on underflow). * #define Check_FLT_ROUNDS 1 if FLT_ROUNDS can assume the values 2 or 3. * #define ROUND_BIASED 1 for IEEE-format with biased rounding. * #define Inaccurate_Divide 1 for IEEE-format with correctly rounded *	products but inaccurate quotients, e.g., for Intel i860. */ #ifdef IEEE_8087#ifdef IEEE_MC68kExactly one of IEEE_8087 or IEEE_MC68k#endif#else#ifndef IEEE_MC68kExactly one of IEEE_8087 or IEEE_MC68k#endif#endif #ifndef Sudden_Underflow#define Sudden_Underflow 0#endif#ifndef Check_FLT_ROUNDS#define Check_FLT_ROUNDS 0#endif#ifndef ROUND_BIASED#define ROUND_BIASED 0#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) */#ifdef IEEE_8087#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) */ #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 */ #define Big0 (Frac_mask1 | Exp_msk1*(DBL_MAX_EXP+Bias-1))#define Big1 0xffffffff #define Kmax 15  structBigint {	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[]; #define n_bigtens 5 #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