nsprpub/pr/src/misc/dtoa.c

Wed, 31 Dec 2014 06:09:35 +0100

author
Michael Schloh von Bennewitz <michael@schloh.com>
date
Wed, 31 Dec 2014 06:09:35 +0100
changeset 0
6474c204b198
permissions
-rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /****************************************************************
     2  *
     3  * The author of this software is David M. Gay.
     4  *
     5  * Copyright (c) 1991, 2000, 2001 by Lucent Technologies.
     6  *
     7  * Permission to use, copy, modify, and distribute this software for any
     8  * purpose without fee is hereby granted, provided that this entire notice
     9  * is included in all copies of any software which is or includes a copy
    10  * or modification of this software and in all copies of the supporting
    11  * documentation for such software.
    12  *
    13  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
    14  * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHOR NOR LUCENT MAKES ANY
    15  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
    16  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
    17  *
    18  ***************************************************************/
    20 /* Please send bug reports to David M. Gay (dmg at acm dot org,
    21  * with " at " changed at "@" and " dot " changed to ".").	*/
    23 /* On a machine with IEEE extended-precision registers, it is
    24  * necessary to specify double-precision (53-bit) rounding precision
    25  * before invoking strtod or dtoa.  If the machine uses (the equivalent
    26  * of) Intel 80x87 arithmetic, the call
    27  *	_control87(PC_53, MCW_PC);
    28  * does this with many compilers.  Whether this or another call is
    29  * appropriate depends on the compiler; for this to work, it may be
    30  * necessary to #include "float.h" or another system-dependent header
    31  * file.
    32  */
    34 /* strtod for IEEE-, VAX-, and IBM-arithmetic machines.
    35  *
    36  * This strtod returns a nearest machine number to the input decimal
    37  * string (or sets errno to ERANGE).  With IEEE arithmetic, ties are
    38  * broken by the IEEE round-even rule.  Otherwise ties are broken by
    39  * biased rounding (add half and chop).
    40  *
    41  * Inspired loosely by William D. Clinger's paper "How to Read Floating
    42  * Point Numbers Accurately" [Proc. ACM SIGPLAN '90, pp. 92-101].
    43  *
    44  * Modifications:
    45  *
    46  *	1. We only require IEEE, IBM, or VAX double-precision
    47  *		arithmetic (not IEEE double-extended).
    48  *	2. We get by with floating-point arithmetic in a case that
    49  *		Clinger missed -- when we're computing d * 10^n
    50  *		for a small integer d and the integer n is not too
    51  *		much larger than 22 (the maximum integer k for which
    52  *		we can represent 10^k exactly), we may be able to
    53  *		compute (d*10^k) * 10^(e-k) with just one roundoff.
    54  *	3. Rather than a bit-at-a-time adjustment of the binary
    55  *		result in the hard case, we use floating-point
    56  *		arithmetic to determine the adjustment to within
    57  *		one bit; only in really hard cases do we need to
    58  *		compute a second residual.
    59  *	4. Because of 3., we don't need a large table of powers of 10
    60  *		for ten-to-e (just some small tables, e.g. of 10^k
    61  *		for 0 <= k <= 22).
    62  */
    64 /*
    65  * #define IEEE_8087 for IEEE-arithmetic machines where the least
    66  *	significant byte has the lowest address.
    67  * #define IEEE_MC68k for IEEE-arithmetic machines where the most
    68  *	significant byte has the lowest address.
    69  * #define Long int on machines with 32-bit ints and 64-bit longs.
    70  * #define IBM for IBM mainframe-style floating-point arithmetic.
    71  * #define VAX for VAX-style floating-point arithmetic (D_floating).
    72  * #define No_leftright to omit left-right logic in fast floating-point
    73  *	computation of dtoa.  This will cause dtoa modes 4 and 5 to be
    74  *	treated the same as modes 2 and 3 for some inputs.
    75  * #define Honor_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3
    76  *	and strtod and dtoa should round accordingly.  Unless Trust_FLT_ROUNDS
    77  *	is also #defined, fegetround() will be queried for the rounding mode.
    78  *	Note that both FLT_ROUNDS and fegetround() are specified by the C99
    79  *	standard (and are specified to be consistent, with fesetround()
    80  *	affecting the value of FLT_ROUNDS), but that some (Linux) systems
    81  *	do not work correctly in this regard, so using fegetround() is more
    82  *	portable than using FLT_ROUNDS directly.
    83  * #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3
    84  *	and Honor_FLT_ROUNDS is not #defined.
    85  * #define RND_PRODQUOT to use rnd_prod and rnd_quot (assembly routines
    86  *	that use extended-precision instructions to compute rounded
    87  *	products and quotients) with IBM.
    88  * #define ROUND_BIASED for IEEE-format with biased rounding and arithmetic
    89  *	that rounds toward +Infinity.
    90  * #define ROUND_BIASED_without_Round_Up for IEEE-format with biased
    91  *	rounding when the underlying floating-point arithmetic uses
    92  *	unbiased rounding.  This prevent using ordinary floating-point
    93  *	arithmetic when the result could be computed with one rounding error.
    94  * #define Inaccurate_Divide for IEEE-format with correctly rounded
    95  *	products but inaccurate quotients, e.g., for Intel i860.
    96  * #define NO_LONG_LONG on machines that do not have a "long long"
    97  *	integer type (of >= 64 bits).  On such machines, you can
    98  *	#define Just_16 to store 16 bits per 32-bit Long when doing
    99  *	high-precision integer arithmetic.  Whether this speeds things
   100  *	up or slows things down depends on the machine and the number
   101  *	being converted.  If long long is available and the name is
   102  *	something other than "long long", #define Llong to be the name,
   103  *	and if "unsigned Llong" does not work as an unsigned version of
   104  *	Llong, #define #ULLong to be the corresponding unsigned type.
   105  * #define KR_headers for old-style C function headers.
   106  * #define Bad_float_h if your system lacks a float.h or if it does not
   107  *	define some or all of DBL_DIG, DBL_MAX_10_EXP, DBL_MAX_EXP,
   108  *	FLT_RADIX, FLT_ROUNDS, and DBL_MAX.
   109  * #define MALLOC your_malloc, where your_malloc(n) acts like malloc(n)
   110  *	if memory is available and otherwise does something you deem
   111  *	appropriate.  If MALLOC is undefined, malloc will be invoked
   112  *	directly -- and assumed always to succeed.  Similarly, if you
   113  *	want something other than the system's free() to be called to
   114  *	recycle memory acquired from MALLOC, #define FREE to be the
   115  *	name of the alternate routine.  (FREE or free is only called in
   116  *	pathological cases, e.g., in a dtoa call after a dtoa return in
   117  *	mode 3 with thousands of digits requested.)
   118  * #define Omit_Private_Memory to omit logic (added Jan. 1998) for making
   119  *	memory allocations from a private pool of memory when possible.
   120  *	When used, the private pool is PRIVATE_MEM bytes long:  2304 bytes,
   121  *	unless #defined to be a different length.  This default length
   122  *	suffices to get rid of MALLOC calls except for unusual cases,
   123  *	such as decimal-to-binary conversion of a very long string of
   124  *	digits.  The longest string dtoa can return is about 751 bytes
   125  *	long.  For conversions by strtod of strings of 800 digits and
   126  *	all dtoa conversions in single-threaded executions with 8-byte
   127  *	pointers, PRIVATE_MEM >= 7400 appears to suffice; with 4-byte
   128  *	pointers, PRIVATE_MEM >= 7112 appears adequate.
   129  * #define NO_INFNAN_CHECK if you do not wish to have INFNAN_CHECK
   130  *	#defined automatically on IEEE systems.  On such systems,
   131  *	when INFNAN_CHECK is #defined, strtod checks
   132  *	for Infinity and NaN (case insensitively).  On some systems
   133  *	(e.g., some HP systems), it may be necessary to #define NAN_WORD0
   134  *	appropriately -- to the most significant word of a quiet NaN.
   135  *	(On HP Series 700/800 machines, -DNAN_WORD0=0x7ff40000 works.)
   136  *	When INFNAN_CHECK is #defined and No_Hex_NaN is not #defined,
   137  *	strtod also accepts (case insensitively) strings of the form
   138  *	NaN(x), where x is a string of hexadecimal digits and spaces;
   139  *	if there is only one string of hexadecimal digits, it is taken
   140  *	for the 52 fraction bits of the resulting NaN; if there are two
   141  *	or more strings of hex digits, the first is for the high 20 bits,
   142  *	the second and subsequent for the low 32 bits, with intervening
   143  *	white space ignored; but if this results in none of the 52
   144  *	fraction bits being on (an IEEE Infinity symbol), then NAN_WORD0
   145  *	and NAN_WORD1 are used instead.
   146  * #define MULTIPLE_THREADS if the system offers preemptively scheduled
   147  *	multiple threads.  In this case, you must provide (or suitably
   148  *	#define) two locks, acquired by ACQUIRE_DTOA_LOCK(n) and freed
   149  *	by FREE_DTOA_LOCK(n) for n = 0 or 1.  (The second lock, accessed
   150  *	in pow5mult, ensures lazy evaluation of only one copy of high
   151  *	powers of 5; omitting this lock would introduce a small
   152  *	probability of wasting memory, but would otherwise be harmless.)
   153  *	You must also invoke freedtoa(s) to free the value s returned by
   154  *	dtoa.  You may do so whether or not MULTIPLE_THREADS is #defined.
   155  * #define NO_IEEE_Scale to disable new (Feb. 1997) logic in strtod that
   156  *	avoids underflows on inputs whose result does not underflow.
   157  *	If you #define NO_IEEE_Scale on a machine that uses IEEE-format
   158  *	floating-point numbers and flushes underflows to zero rather
   159  *	than implementing gradual underflow, then you must also #define
   160  *	Sudden_Underflow.
   161  * #define USE_LOCALE to use the current locale's decimal_point value.
   162  * #define SET_INEXACT if IEEE arithmetic is being used and extra
   163  *	computation should be done to set the inexact flag when the
   164  *	result is inexact and avoid setting inexact when the result
   165  *	is exact.  In this case, dtoa.c must be compiled in
   166  *	an environment, perhaps provided by #include "dtoa.c" in a
   167  *	suitable wrapper, that defines two functions,
   168  *		int get_inexact(void);
   169  *		void clear_inexact(void);
   170  *	such that get_inexact() returns a nonzero value if the
   171  *	inexact bit is already set, and clear_inexact() sets the
   172  *	inexact bit to 0.  When SET_INEXACT is #defined, strtod
   173  *	also does extra computations to set the underflow and overflow
   174  *	flags when appropriate (i.e., when the result is tiny and
   175  *	inexact or when it is a numeric value rounded to +-infinity).
   176  * #define NO_ERRNO if strtod should not assign errno = ERANGE when
   177  *	the result overflows to +-Infinity or underflows to 0.
   178  * #define NO_HEX_FP to omit recognition of hexadecimal floating-point
   179  *	values by strtod.
   180  * #define NO_STRTOD_BIGCOMP (on IEEE-arithmetic systems only for now)
   181  *	to disable logic for "fast" testing of very long input strings
   182  *	to strtod.  This testing proceeds by initially truncating the
   183  *	input string, then if necessary comparing the whole string with
   184  *	a decimal expansion to decide close cases. This logic is only
   185  *	used for input more than STRTOD_DIGLIM digits long (default 40).
   186  */
   188 #ifndef Long
   189 #define Long long
   190 #endif
   191 #ifndef ULong
   192 typedef unsigned Long ULong;
   193 #endif
   195 #ifdef DEBUG
   196 #include "stdio.h"
   197 #define Bug(x) {fprintf(stderr, "%s\n", x); exit(1);}
   198 #endif
   200 #include "stdlib.h"
   201 #include "string.h"
   203 #ifdef USE_LOCALE
   204 #include "locale.h"
   205 #endif
   207 #ifdef Honor_FLT_ROUNDS
   208 #ifndef Trust_FLT_ROUNDS
   209 #include <fenv.h>
   210 #endif
   211 #endif
   213 #ifdef MALLOC
   214 #ifdef KR_headers
   215 extern char *MALLOC();
   216 #else
   217 extern void *MALLOC(size_t);
   218 #endif
   219 #else
   220 #define MALLOC malloc
   221 #endif
   223 #ifndef Omit_Private_Memory
   224 #ifndef PRIVATE_MEM
   225 #define PRIVATE_MEM 2304
   226 #endif
   227 #define PRIVATE_mem ((PRIVATE_MEM+sizeof(double)-1)/sizeof(double))
   228 static double private_mem[PRIVATE_mem], *pmem_next = private_mem;
   229 #endif
   231 #undef IEEE_Arith
   232 #undef Avoid_Underflow
   233 #ifdef IEEE_MC68k
   234 #define IEEE_Arith
   235 #endif
   236 #ifdef IEEE_8087
   237 #define IEEE_Arith
   238 #endif
   240 #ifdef IEEE_Arith
   241 #ifndef NO_INFNAN_CHECK
   242 #undef INFNAN_CHECK
   243 #define INFNAN_CHECK
   244 #endif
   245 #else
   246 #undef INFNAN_CHECK
   247 #define NO_STRTOD_BIGCOMP
   248 #endif
   250 #include "errno.h"
   252 #ifdef Bad_float_h
   254 #ifdef IEEE_Arith
   255 #define DBL_DIG 15
   256 #define DBL_MAX_10_EXP 308
   257 #define DBL_MAX_EXP 1024
   258 #define FLT_RADIX 2
   259 #endif /*IEEE_Arith*/
   261 #ifdef IBM
   262 #define DBL_DIG 16
   263 #define DBL_MAX_10_EXP 75
   264 #define DBL_MAX_EXP 63
   265 #define FLT_RADIX 16
   266 #define DBL_MAX 7.2370055773322621e+75
   267 #endif
   269 #ifdef VAX
   270 #define DBL_DIG 16
   271 #define DBL_MAX_10_EXP 38
   272 #define DBL_MAX_EXP 127
   273 #define FLT_RADIX 2
   274 #define DBL_MAX 1.7014118346046923e+38
   275 #endif
   277 #ifndef LONG_MAX
   278 #define LONG_MAX 2147483647
   279 #endif
   281 #else /* ifndef Bad_float_h */
   282 #include "float.h"
   283 #endif /* Bad_float_h */
   285 #ifndef __MATH_H__
   286 #include "math.h"
   287 #endif
   289 #ifdef __cplusplus
   290 extern "C" {
   291 #endif
   293 #ifndef CONST
   294 #ifdef KR_headers
   295 #define CONST /* blank */
   296 #else
   297 #define CONST const
   298 #endif
   299 #endif
   301 #if defined(IEEE_8087) + defined(IEEE_MC68k) + defined(VAX) + defined(IBM) != 1
   302 Exactly one of IEEE_8087, IEEE_MC68k, VAX, or IBM should be defined.
   303 #endif
   305 typedef union { double d; ULong L[2]; } U;
   307 #ifdef IEEE_8087
   308 #define word0(x) (x)->L[1]
   309 #define word1(x) (x)->L[0]
   310 #else
   311 #define word0(x) (x)->L[0]
   312 #define word1(x) (x)->L[1]
   313 #endif
   314 #define dval(x) (x)->d
   316 #ifndef STRTOD_DIGLIM
   317 #define STRTOD_DIGLIM 40
   318 #endif
   320 #ifdef DIGLIM_DEBUG
   321 extern int strtod_diglim;
   322 #else
   323 #define strtod_diglim STRTOD_DIGLIM
   324 #endif
   326 /* The following definition of Storeinc is appropriate for MIPS processors.
   327  * An alternative that might be better on some machines is
   328  * #define Storeinc(a,b,c) (*a++ = b << 16 | c & 0xffff)
   329  */
   330 #if defined(IEEE_8087) + defined(VAX)
   331 #define Storeinc(a,b,c) (((unsigned short *)a)[1] = (unsigned short)b, \
   332 ((unsigned short *)a)[0] = (unsigned short)c, a++)
   333 #else
   334 #define Storeinc(a,b,c) (((unsigned short *)a)[0] = (unsigned short)b, \
   335 ((unsigned short *)a)[1] = (unsigned short)c, a++)
   336 #endif
   338 /* #define P DBL_MANT_DIG */
   339 /* Ten_pmax = floor(P*log(2)/log(5)) */
   340 /* Bletch = (highest power of 2 < DBL_MAX_10_EXP) / 16 */
   341 /* Quick_max = floor((P-1)*log(FLT_RADIX)/log(10) - 1) */
   342 /* Int_max = floor(P*log(FLT_RADIX)/log(10) - 1) */
   344 #ifdef IEEE_Arith
   345 #define Exp_shift  20
   346 #define Exp_shift1 20
   347 #define Exp_msk1    0x100000
   348 #define Exp_msk11   0x100000
   349 #define Exp_mask  0x7ff00000
   350 #define P 53
   351 #define Nbits 53
   352 #define Bias 1023
   353 #define Emax 1023
   354 #define Emin (-1022)
   355 #define Exp_1  0x3ff00000
   356 #define Exp_11 0x3ff00000
   357 #define Ebits 11
   358 #define Frac_mask  0xfffff
   359 #define Frac_mask1 0xfffff
   360 #define Ten_pmax 22
   361 #define Bletch 0x10
   362 #define Bndry_mask  0xfffff
   363 #define Bndry_mask1 0xfffff
   364 #define LSB 1
   365 #define Sign_bit 0x80000000
   366 #define Log2P 1
   367 #define Tiny0 0
   368 #define Tiny1 1
   369 #define Quick_max 14
   370 #define Int_max 14
   371 #ifndef NO_IEEE_Scale
   372 #define Avoid_Underflow
   373 #ifdef Flush_Denorm	/* debugging option */
   374 #undef Sudden_Underflow
   375 #endif
   376 #endif
   378 #ifndef Flt_Rounds
   379 #ifdef FLT_ROUNDS
   380 #define Flt_Rounds FLT_ROUNDS
   381 #else
   382 #define Flt_Rounds 1
   383 #endif
   384 #endif /*Flt_Rounds*/
   386 #ifdef Honor_FLT_ROUNDS
   387 #undef Check_FLT_ROUNDS
   388 #define Check_FLT_ROUNDS
   389 #else
   390 #define Rounding Flt_Rounds
   391 #endif
   393 #else /* ifndef IEEE_Arith */
   394 #undef Check_FLT_ROUNDS
   395 #undef Honor_FLT_ROUNDS
   396 #undef SET_INEXACT
   397 #undef  Sudden_Underflow
   398 #define Sudden_Underflow
   399 #ifdef IBM
   400 #undef Flt_Rounds
   401 #define Flt_Rounds 0
   402 #define Exp_shift  24
   403 #define Exp_shift1 24
   404 #define Exp_msk1   0x1000000
   405 #define Exp_msk11  0x1000000
   406 #define Exp_mask  0x7f000000
   407 #define P 14
   408 #define Nbits 56
   409 #define Bias 65
   410 #define Emax 248
   411 #define Emin (-260)
   412 #define Exp_1  0x41000000
   413 #define Exp_11 0x41000000
   414 #define Ebits 8	/* exponent has 7 bits, but 8 is the right value in b2d */
   415 #define Frac_mask  0xffffff
   416 #define Frac_mask1 0xffffff
   417 #define Bletch 4
   418 #define Ten_pmax 22
   419 #define Bndry_mask  0xefffff
   420 #define Bndry_mask1 0xffffff
   421 #define LSB 1
   422 #define Sign_bit 0x80000000
   423 #define Log2P 4
   424 #define Tiny0 0x100000
   425 #define Tiny1 0
   426 #define Quick_max 14
   427 #define Int_max 15
   428 #else /* VAX */
   429 #undef Flt_Rounds
   430 #define Flt_Rounds 1
   431 #define Exp_shift  23
   432 #define Exp_shift1 7
   433 #define Exp_msk1    0x80
   434 #define Exp_msk11   0x800000
   435 #define Exp_mask  0x7f80
   436 #define P 56
   437 #define Nbits 56
   438 #define Bias 129
   439 #define Emax 126
   440 #define Emin (-129)
   441 #define Exp_1  0x40800000
   442 #define Exp_11 0x4080
   443 #define Ebits 8
   444 #define Frac_mask  0x7fffff
   445 #define Frac_mask1 0xffff007f
   446 #define Ten_pmax 24
   447 #define Bletch 2
   448 #define Bndry_mask  0xffff007f
   449 #define Bndry_mask1 0xffff007f
   450 #define LSB 0x10000
   451 #define Sign_bit 0x8000
   452 #define Log2P 1
   453 #define Tiny0 0x80
   454 #define Tiny1 0
   455 #define Quick_max 15
   456 #define Int_max 15
   457 #endif /* IBM, VAX */
   458 #endif /* IEEE_Arith */
   460 #ifndef IEEE_Arith
   461 #define ROUND_BIASED
   462 #else
   463 #ifdef ROUND_BIASED_without_Round_Up
   464 #undef  ROUND_BIASED
   465 #define ROUND_BIASED
   466 #endif
   467 #endif
   469 #ifdef RND_PRODQUOT
   470 #define rounded_product(a,b) a = rnd_prod(a, b)
   471 #define rounded_quotient(a,b) a = rnd_quot(a, b)
   472 #ifdef KR_headers
   473 extern double rnd_prod(), rnd_quot();
   474 #else
   475 extern double rnd_prod(double, double), rnd_quot(double, double);
   476 #endif
   477 #else
   478 #define rounded_product(a,b) a *= b
   479 #define rounded_quotient(a,b) a /= b
   480 #endif
   482 #define Big0 (Frac_mask1 | Exp_msk1*(DBL_MAX_EXP+Bias-1))
   483 #define Big1 0xffffffff
   485 #ifndef Pack_32
   486 #define Pack_32
   487 #endif
   489 typedef struct BCinfo BCinfo;
   490  struct
   491 BCinfo { int dp0, dp1, dplen, dsign, e0, inexact, nd, nd0, rounding, scale, uflchk; };
   493 #ifdef KR_headers
   494 #define FFFFFFFF ((((unsigned long)0xffff)<<16)|(unsigned long)0xffff)
   495 #else
   496 #define FFFFFFFF 0xffffffffUL
   497 #endif
   499 #ifdef NO_LONG_LONG
   500 #undef ULLong
   501 #ifdef Just_16
   502 #undef Pack_32
   503 /* When Pack_32 is not defined, we store 16 bits per 32-bit Long.
   504  * This makes some inner loops simpler and sometimes saves work
   505  * during multiplications, but it often seems to make things slightly
   506  * slower.  Hence the default is now to store 32 bits per Long.
   507  */
   508 #endif
   509 #else	/* long long available */
   510 #ifndef Llong
   511 #define Llong long long
   512 #endif
   513 #ifndef ULLong
   514 #define ULLong unsigned Llong
   515 #endif
   516 #endif /* NO_LONG_LONG */
   518 #ifndef MULTIPLE_THREADS
   519 #define ACQUIRE_DTOA_LOCK(n)	/*nothing*/
   520 #define FREE_DTOA_LOCK(n)	/*nothing*/
   521 #endif
   523 #define Kmax 7
   525 #ifdef __cplusplus
   526 extern "C" double strtod(const char *s00, char **se);
   527 extern "C" char *dtoa(double d, int mode, int ndigits,
   528 			int *decpt, int *sign, char **rve);
   529 #endif
   531  struct
   532 Bigint {
   533 	struct Bigint *next;
   534 	int k, maxwds, sign, wds;
   535 	ULong x[1];
   536 	};
   538  typedef struct Bigint Bigint;
   540  static Bigint *freelist[Kmax+1];
   542  static Bigint *
   543 Balloc
   544 #ifdef KR_headers
   545 	(k) int k;
   546 #else
   547 	(int k)
   548 #endif
   549 {
   550 	int x;
   551 	Bigint *rv;
   552 #ifndef Omit_Private_Memory
   553 	unsigned int len;
   554 #endif
   556 	ACQUIRE_DTOA_LOCK(0);
   557 	/* The k > Kmax case does not need ACQUIRE_DTOA_LOCK(0), */
   558 	/* but this case seems very unlikely. */
   559 	if (k <= Kmax && (rv = freelist[k]))
   560 		freelist[k] = rv->next;
   561 	else {
   562 		x = 1 << k;
   563 #ifdef Omit_Private_Memory
   564 		rv = (Bigint *)MALLOC(sizeof(Bigint) + (x-1)*sizeof(ULong));
   565 #else
   566 		len = (sizeof(Bigint) + (x-1)*sizeof(ULong) + sizeof(double) - 1)
   567 			/sizeof(double);
   568 		if (k <= Kmax && pmem_next - private_mem + len <= PRIVATE_mem) {
   569 			rv = (Bigint*)pmem_next;
   570 			pmem_next += len;
   571 			}
   572 		else
   573 			rv = (Bigint*)MALLOC(len*sizeof(double));
   574 #endif
   575 		rv->k = k;
   576 		rv->maxwds = x;
   577 		}
   578 	FREE_DTOA_LOCK(0);
   579 	rv->sign = rv->wds = 0;
   580 	return rv;
   581 	}
   583  static void
   584 Bfree
   585 #ifdef KR_headers
   586 	(v) Bigint *v;
   587 #else
   588 	(Bigint *v)
   589 #endif
   590 {
   591 	if (v) {
   592 		if (v->k > Kmax)
   593 #ifdef FREE
   594 			FREE((void*)v);
   595 #else
   596 			free((void*)v);
   597 #endif
   598 		else {
   599 			ACQUIRE_DTOA_LOCK(0);
   600 			v->next = freelist[v->k];
   601 			freelist[v->k] = v;
   602 			FREE_DTOA_LOCK(0);
   603 			}
   604 		}
   605 	}
   607 #define Bcopy(x,y) memcpy((char *)&x->sign, (char *)&y->sign, \
   608 y->wds*sizeof(Long) + 2*sizeof(int))
   610  static Bigint *
   611 multadd
   612 #ifdef KR_headers
   613 	(b, m, a) Bigint *b; int m, a;
   614 #else
   615 	(Bigint *b, int m, int a)	/* multiply by m and add a */
   616 #endif
   617 {
   618 	int i, wds;
   619 #ifdef ULLong
   620 	ULong *x;
   621 	ULLong carry, y;
   622 #else
   623 	ULong carry, *x, y;
   624 #ifdef Pack_32
   625 	ULong xi, z;
   626 #endif
   627 #endif
   628 	Bigint *b1;
   630 	wds = b->wds;
   631 	x = b->x;
   632 	i = 0;
   633 	carry = a;
   634 	do {
   635 #ifdef ULLong
   636 		y = *x * (ULLong)m + carry;
   637 		carry = y >> 32;
   638 		*x++ = y & FFFFFFFF;
   639 #else
   640 #ifdef Pack_32
   641 		xi = *x;
   642 		y = (xi & 0xffff) * m + carry;
   643 		z = (xi >> 16) * m + (y >> 16);
   644 		carry = z >> 16;
   645 		*x++ = (z << 16) + (y & 0xffff);
   646 #else
   647 		y = *x * m + carry;
   648 		carry = y >> 16;
   649 		*x++ = y & 0xffff;
   650 #endif
   651 #endif
   652 		}
   653 		while(++i < wds);
   654 	if (carry) {
   655 		if (wds >= b->maxwds) {
   656 			b1 = Balloc(b->k+1);
   657 			Bcopy(b1, b);
   658 			Bfree(b);
   659 			b = b1;
   660 			}
   661 		b->x[wds++] = carry;
   662 		b->wds = wds;
   663 		}
   664 	return b;
   665 	}
   667  static Bigint *
   668 s2b
   669 #ifdef KR_headers
   670 	(s, nd0, nd, y9, dplen) CONST char *s; int nd0, nd, dplen; ULong y9;
   671 #else
   672 	(const char *s, int nd0, int nd, ULong y9, int dplen)
   673 #endif
   674 {
   675 	Bigint *b;
   676 	int i, k;
   677 	Long x, y;
   679 	x = (nd + 8) / 9;
   680 	for(k = 0, y = 1; x > y; y <<= 1, k++) ;
   681 #ifdef Pack_32
   682 	b = Balloc(k);
   683 	b->x[0] = y9;
   684 	b->wds = 1;
   685 #else
   686 	b = Balloc(k+1);
   687 	b->x[0] = y9 & 0xffff;
   688 	b->wds = (b->x[1] = y9 >> 16) ? 2 : 1;
   689 #endif
   691 	i = 9;
   692 	if (9 < nd0) {
   693 		s += 9;
   694 		do b = multadd(b, 10, *s++ - '0');
   695 			while(++i < nd0);
   696 		s += dplen;
   697 		}
   698 	else
   699 		s += dplen + 9;
   700 	for(; i < nd; i++)
   701 		b = multadd(b, 10, *s++ - '0');
   702 	return b;
   703 	}
   705  static int
   706 hi0bits
   707 #ifdef KR_headers
   708 	(x) ULong x;
   709 #else
   710 	(ULong x)
   711 #endif
   712 {
   713 	int k = 0;
   715 	if (!(x & 0xffff0000)) {
   716 		k = 16;
   717 		x <<= 16;
   718 		}
   719 	if (!(x & 0xff000000)) {
   720 		k += 8;
   721 		x <<= 8;
   722 		}
   723 	if (!(x & 0xf0000000)) {
   724 		k += 4;
   725 		x <<= 4;
   726 		}
   727 	if (!(x & 0xc0000000)) {
   728 		k += 2;
   729 		x <<= 2;
   730 		}
   731 	if (!(x & 0x80000000)) {
   732 		k++;
   733 		if (!(x & 0x40000000))
   734 			return 32;
   735 		}
   736 	return k;
   737 	}
   739  static int
   740 lo0bits
   741 #ifdef KR_headers
   742 	(y) ULong *y;
   743 #else
   744 	(ULong *y)
   745 #endif
   746 {
   747 	int k;
   748 	ULong x = *y;
   750 	if (x & 7) {
   751 		if (x & 1)
   752 			return 0;
   753 		if (x & 2) {
   754 			*y = x >> 1;
   755 			return 1;
   756 			}
   757 		*y = x >> 2;
   758 		return 2;
   759 		}
   760 	k = 0;
   761 	if (!(x & 0xffff)) {
   762 		k = 16;
   763 		x >>= 16;
   764 		}
   765 	if (!(x & 0xff)) {
   766 		k += 8;
   767 		x >>= 8;
   768 		}
   769 	if (!(x & 0xf)) {
   770 		k += 4;
   771 		x >>= 4;
   772 		}
   773 	if (!(x & 0x3)) {
   774 		k += 2;
   775 		x >>= 2;
   776 		}
   777 	if (!(x & 1)) {
   778 		k++;
   779 		x >>= 1;
   780 		if (!x)
   781 			return 32;
   782 		}
   783 	*y = x;
   784 	return k;
   785 	}
   787  static Bigint *
   788 i2b
   789 #ifdef KR_headers
   790 	(i) int i;
   791 #else
   792 	(int i)
   793 #endif
   794 {
   795 	Bigint *b;
   797 	b = Balloc(1);
   798 	b->x[0] = i;
   799 	b->wds = 1;
   800 	return b;
   801 	}
   803  static Bigint *
   804 mult
   805 #ifdef KR_headers
   806 	(a, b) Bigint *a, *b;
   807 #else
   808 	(Bigint *a, Bigint *b)
   809 #endif
   810 {
   811 	Bigint *c;
   812 	int k, wa, wb, wc;
   813 	ULong *x, *xa, *xae, *xb, *xbe, *xc, *xc0;
   814 	ULong y;
   815 #ifdef ULLong
   816 	ULLong carry, z;
   817 #else
   818 	ULong carry, z;
   819 #ifdef Pack_32
   820 	ULong z2;
   821 #endif
   822 #endif
   824 	if (a->wds < b->wds) {
   825 		c = a;
   826 		a = b;
   827 		b = c;
   828 		}
   829 	k = a->k;
   830 	wa = a->wds;
   831 	wb = b->wds;
   832 	wc = wa + wb;
   833 	if (wc > a->maxwds)
   834 		k++;
   835 	c = Balloc(k);
   836 	for(x = c->x, xa = x + wc; x < xa; x++)
   837 		*x = 0;
   838 	xa = a->x;
   839 	xae = xa + wa;
   840 	xb = b->x;
   841 	xbe = xb + wb;
   842 	xc0 = c->x;
   843 #ifdef ULLong
   844 	for(; xb < xbe; xc0++) {
   845 		if ((y = *xb++)) {
   846 			x = xa;
   847 			xc = xc0;
   848 			carry = 0;
   849 			do {
   850 				z = *x++ * (ULLong)y + *xc + carry;
   851 				carry = z >> 32;
   852 				*xc++ = z & FFFFFFFF;
   853 				}
   854 				while(x < xae);
   855 			*xc = carry;
   856 			}
   857 		}
   858 #else
   859 #ifdef Pack_32
   860 	for(; xb < xbe; xb++, xc0++) {
   861 		if (y = *xb & 0xffff) {
   862 			x = xa;
   863 			xc = xc0;
   864 			carry = 0;
   865 			do {
   866 				z = (*x & 0xffff) * y + (*xc & 0xffff) + carry;
   867 				carry = z >> 16;
   868 				z2 = (*x++ >> 16) * y + (*xc >> 16) + carry;
   869 				carry = z2 >> 16;
   870 				Storeinc(xc, z2, z);
   871 				}
   872 				while(x < xae);
   873 			*xc = carry;
   874 			}
   875 		if (y = *xb >> 16) {
   876 			x = xa;
   877 			xc = xc0;
   878 			carry = 0;
   879 			z2 = *xc;
   880 			do {
   881 				z = (*x & 0xffff) * y + (*xc >> 16) + carry;
   882 				carry = z >> 16;
   883 				Storeinc(xc, z, z2);
   884 				z2 = (*x++ >> 16) * y + (*xc & 0xffff) + carry;
   885 				carry = z2 >> 16;
   886 				}
   887 				while(x < xae);
   888 			*xc = z2;
   889 			}
   890 		}
   891 #else
   892 	for(; xb < xbe; xc0++) {
   893 		if (y = *xb++) {
   894 			x = xa;
   895 			xc = xc0;
   896 			carry = 0;
   897 			do {
   898 				z = *x++ * y + *xc + carry;
   899 				carry = z >> 16;
   900 				*xc++ = z & 0xffff;
   901 				}
   902 				while(x < xae);
   903 			*xc = carry;
   904 			}
   905 		}
   906 #endif
   907 #endif
   908 	for(xc0 = c->x, xc = xc0 + wc; wc > 0 && !*--xc; --wc) ;
   909 	c->wds = wc;
   910 	return c;
   911 	}
   913  static Bigint *p5s;
   915  static Bigint *
   916 pow5mult
   917 #ifdef KR_headers
   918 	(b, k) Bigint *b; int k;
   919 #else
   920 	(Bigint *b, int k)
   921 #endif
   922 {
   923 	Bigint *b1, *p5, *p51;
   924 	int i;
   925 	static int p05[3] = { 5, 25, 125 };
   927 	if ((i = k & 3))
   928 		b = multadd(b, p05[i-1], 0);
   930 	if (!(k >>= 2))
   931 		return b;
   932 	if (!(p5 = p5s)) {
   933 		/* first time */
   934 #ifdef MULTIPLE_THREADS
   935 		ACQUIRE_DTOA_LOCK(1);
   936 		if (!(p5 = p5s)) {
   937 			p5 = p5s = i2b(625);
   938 			p5->next = 0;
   939 			}
   940 		FREE_DTOA_LOCK(1);
   941 #else
   942 		p5 = p5s = i2b(625);
   943 		p5->next = 0;
   944 #endif
   945 		}
   946 	for(;;) {
   947 		if (k & 1) {
   948 			b1 = mult(b, p5);
   949 			Bfree(b);
   950 			b = b1;
   951 			}
   952 		if (!(k >>= 1))
   953 			break;
   954 		if (!(p51 = p5->next)) {
   955 #ifdef MULTIPLE_THREADS
   956 			ACQUIRE_DTOA_LOCK(1);
   957 			if (!(p51 = p5->next)) {
   958 				p51 = p5->next = mult(p5,p5);
   959 				p51->next = 0;
   960 				}
   961 			FREE_DTOA_LOCK(1);
   962 #else
   963 			p51 = p5->next = mult(p5,p5);
   964 			p51->next = 0;
   965 #endif
   966 			}
   967 		p5 = p51;
   968 		}
   969 	return b;
   970 	}
   972  static Bigint *
   973 lshift
   974 #ifdef KR_headers
   975 	(b, k) Bigint *b; int k;
   976 #else
   977 	(Bigint *b, int k)
   978 #endif
   979 {
   980 	int i, k1, n, n1;
   981 	Bigint *b1;
   982 	ULong *x, *x1, *xe, z;
   984 #ifdef Pack_32
   985 	n = k >> 5;
   986 #else
   987 	n = k >> 4;
   988 #endif
   989 	k1 = b->k;
   990 	n1 = n + b->wds + 1;
   991 	for(i = b->maxwds; n1 > i; i <<= 1)
   992 		k1++;
   993 	b1 = Balloc(k1);
   994 	x1 = b1->x;
   995 	for(i = 0; i < n; i++)
   996 		*x1++ = 0;
   997 	x = b->x;
   998 	xe = x + b->wds;
   999 #ifdef Pack_32
  1000 	if (k &= 0x1f) {
  1001 		k1 = 32 - k;
  1002 		z = 0;
  1003 		do {
  1004 			*x1++ = *x << k | z;
  1005 			z = *x++ >> k1;
  1007 			while(x < xe);
  1008 		if ((*x1 = z))
  1009 			++n1;
  1011 #else
  1012 	if (k &= 0xf) {
  1013 		k1 = 16 - k;
  1014 		z = 0;
  1015 		do {
  1016 			*x1++ = *x << k  & 0xffff | z;
  1017 			z = *x++ >> k1;
  1019 			while(x < xe);
  1020 		if (*x1 = z)
  1021 			++n1;
  1023 #endif
  1024 	else do
  1025 		*x1++ = *x++;
  1026 		while(x < xe);
  1027 	b1->wds = n1 - 1;
  1028 	Bfree(b);
  1029 	return b1;
  1032  static int
  1033 cmp
  1034 #ifdef KR_headers
  1035 	(a, b) Bigint *a, *b;
  1036 #else
  1037 	(Bigint *a, Bigint *b)
  1038 #endif
  1040 	ULong *xa, *xa0, *xb, *xb0;
  1041 	int i, j;
  1043 	i = a->wds;
  1044 	j = b->wds;
  1045 #ifdef DEBUG
  1046 	if (i > 1 && !a->x[i-1])
  1047 		Bug("cmp called with a->x[a->wds-1] == 0");
  1048 	if (j > 1 && !b->x[j-1])
  1049 		Bug("cmp called with b->x[b->wds-1] == 0");
  1050 #endif
  1051 	if (i -= j)
  1052 		return i;
  1053 	xa0 = a->x;
  1054 	xa = xa0 + j;
  1055 	xb0 = b->x;
  1056 	xb = xb0 + j;
  1057 	for(;;) {
  1058 		if (*--xa != *--xb)
  1059 			return *xa < *xb ? -1 : 1;
  1060 		if (xa <= xa0)
  1061 			break;
  1063 	return 0;
  1066  static Bigint *
  1067 diff
  1068 #ifdef KR_headers
  1069 	(a, b) Bigint *a, *b;
  1070 #else
  1071 	(Bigint *a, Bigint *b)
  1072 #endif
  1074 	Bigint *c;
  1075 	int i, wa, wb;
  1076 	ULong *xa, *xae, *xb, *xbe, *xc;
  1077 #ifdef ULLong
  1078 	ULLong borrow, y;
  1079 #else
  1080 	ULong borrow, y;
  1081 #ifdef Pack_32
  1082 	ULong z;
  1083 #endif
  1084 #endif
  1086 	i = cmp(a,b);
  1087 	if (!i) {
  1088 		c = Balloc(0);
  1089 		c->wds = 1;
  1090 		c->x[0] = 0;
  1091 		return c;
  1093 	if (i < 0) {
  1094 		c = a;
  1095 		a = b;
  1096 		b = c;
  1097 		i = 1;
  1099 	else
  1100 		i = 0;
  1101 	c = Balloc(a->k);
  1102 	c->sign = i;
  1103 	wa = a->wds;
  1104 	xa = a->x;
  1105 	xae = xa + wa;
  1106 	wb = b->wds;
  1107 	xb = b->x;
  1108 	xbe = xb + wb;
  1109 	xc = c->x;
  1110 	borrow = 0;
  1111 #ifdef ULLong
  1112 	do {
  1113 		y = (ULLong)*xa++ - *xb++ - borrow;
  1114 		borrow = y >> 32 & (ULong)1;
  1115 		*xc++ = y & FFFFFFFF;
  1117 		while(xb < xbe);
  1118 	while(xa < xae) {
  1119 		y = *xa++ - borrow;
  1120 		borrow = y >> 32 & (ULong)1;
  1121 		*xc++ = y & FFFFFFFF;
  1123 #else
  1124 #ifdef Pack_32
  1125 	do {
  1126 		y = (*xa & 0xffff) - (*xb & 0xffff) - borrow;
  1127 		borrow = (y & 0x10000) >> 16;
  1128 		z = (*xa++ >> 16) - (*xb++ >> 16) - borrow;
  1129 		borrow = (z & 0x10000) >> 16;
  1130 		Storeinc(xc, z, y);
  1132 		while(xb < xbe);
  1133 	while(xa < xae) {
  1134 		y = (*xa & 0xffff) - borrow;
  1135 		borrow = (y & 0x10000) >> 16;
  1136 		z = (*xa++ >> 16) - borrow;
  1137 		borrow = (z & 0x10000) >> 16;
  1138 		Storeinc(xc, z, y);
  1140 #else
  1141 	do {
  1142 		y = *xa++ - *xb++ - borrow;
  1143 		borrow = (y & 0x10000) >> 16;
  1144 		*xc++ = y & 0xffff;
  1146 		while(xb < xbe);
  1147 	while(xa < xae) {
  1148 		y = *xa++ - borrow;
  1149 		borrow = (y & 0x10000) >> 16;
  1150 		*xc++ = y & 0xffff;
  1152 #endif
  1153 #endif
  1154 	while(!*--xc)
  1155 		wa--;
  1156 	c->wds = wa;
  1157 	return c;
  1160  static double
  1161 ulp
  1162 #ifdef KR_headers
  1163 	(x) U *x;
  1164 #else
  1165 	(U *x)
  1166 #endif
  1168 	Long L;
  1169 	U u;
  1171 	L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1;
  1172 #ifndef Avoid_Underflow
  1173 #ifndef Sudden_Underflow
  1174 	if (L > 0) {
  1175 #endif
  1176 #endif
  1177 #ifdef IBM
  1178 		L |= Exp_msk1 >> 4;
  1179 #endif
  1180 		word0(&u) = L;
  1181 		word1(&u) = 0;
  1182 #ifndef Avoid_Underflow
  1183 #ifndef Sudden_Underflow
  1185 	else {
  1186 		L = -L >> Exp_shift;
  1187 		if (L < Exp_shift) {
  1188 			word0(&u) = 0x80000 >> L;
  1189 			word1(&u) = 0;
  1191 		else {
  1192 			word0(&u) = 0;
  1193 			L -= Exp_shift;
  1194 			word1(&u) = L >= 31 ? 1 : 1 << 31 - L;
  1197 #endif
  1198 #endif
  1199 	return dval(&u);
  1202  static double
  1203 b2d
  1204 #ifdef KR_headers
  1205 	(a, e) Bigint *a; int *e;
  1206 #else
  1207 	(Bigint *a, int *e)
  1208 #endif
  1210 	ULong *xa, *xa0, w, y, z;
  1211 	int k;
  1212 	U d;
  1213 #ifdef VAX
  1214 	ULong d0, d1;
  1215 #else
  1216 #define d0 word0(&d)
  1217 #define d1 word1(&d)
  1218 #endif
  1220 	xa0 = a->x;
  1221 	xa = xa0 + a->wds;
  1222 	y = *--xa;
  1223 #ifdef DEBUG
  1224 	if (!y) Bug("zero y in b2d");
  1225 #endif
  1226 	k = hi0bits(y);
  1227 	*e = 32 - k;
  1228 #ifdef Pack_32
  1229 	if (k < Ebits) {
  1230 		d0 = Exp_1 | y >> (Ebits - k);
  1231 		w = xa > xa0 ? *--xa : 0;
  1232 		d1 = y << ((32-Ebits) + k) | w >> (Ebits - k);
  1233 		goto ret_d;
  1235 	z = xa > xa0 ? *--xa : 0;
  1236 	if (k -= Ebits) {
  1237 		d0 = Exp_1 | y << k | z >> (32 - k);
  1238 		y = xa > xa0 ? *--xa : 0;
  1239 		d1 = z << k | y >> (32 - k);
  1241 	else {
  1242 		d0 = Exp_1 | y;
  1243 		d1 = z;
  1245 #else
  1246 	if (k < Ebits + 16) {
  1247 		z = xa > xa0 ? *--xa : 0;
  1248 		d0 = Exp_1 | y << k - Ebits | z >> Ebits + 16 - k;
  1249 		w = xa > xa0 ? *--xa : 0;
  1250 		y = xa > xa0 ? *--xa : 0;
  1251 		d1 = z << k + 16 - Ebits | w << k - Ebits | y >> 16 + Ebits - k;
  1252 		goto ret_d;
  1254 	z = xa > xa0 ? *--xa : 0;
  1255 	w = xa > xa0 ? *--xa : 0;
  1256 	k -= Ebits + 16;
  1257 	d0 = Exp_1 | y << k + 16 | z << k | w >> 16 - k;
  1258 	y = xa > xa0 ? *--xa : 0;
  1259 	d1 = w << k + 16 | y << k;
  1260 #endif
  1261  ret_d:
  1262 #ifdef VAX
  1263 	word0(&d) = d0 >> 16 | d0 << 16;
  1264 	word1(&d) = d1 >> 16 | d1 << 16;
  1265 #else
  1266 #undef d0
  1267 #undef d1
  1268 #endif
  1269 	return dval(&d);
  1272  static Bigint *
  1273 d2b
  1274 #ifdef KR_headers
  1275 	(d, e, bits) U *d; int *e, *bits;
  1276 #else
  1277 	(U *d, int *e, int *bits)
  1278 #endif
  1280 	Bigint *b;
  1281 	int de, k;
  1282 	ULong *x, y, z;
  1283 #ifndef Sudden_Underflow
  1284 	int i;
  1285 #endif
  1286 #ifdef VAX
  1287 	ULong d0, d1;
  1288 	d0 = word0(d) >> 16 | word0(d) << 16;
  1289 	d1 = word1(d) >> 16 | word1(d) << 16;
  1290 #else
  1291 #define d0 word0(d)
  1292 #define d1 word1(d)
  1293 #endif
  1295 #ifdef Pack_32
  1296 	b = Balloc(1);
  1297 #else
  1298 	b = Balloc(2);
  1299 #endif
  1300 	x = b->x;
  1302 	z = d0 & Frac_mask;
  1303 	d0 &= 0x7fffffff;	/* clear sign bit, which we ignore */
  1304 #ifdef Sudden_Underflow
  1305 	de = (int)(d0 >> Exp_shift);
  1306 #ifndef IBM
  1307 	z |= Exp_msk11;
  1308 #endif
  1309 #else
  1310 	if ((de = (int)(d0 >> Exp_shift)))
  1311 		z |= Exp_msk1;
  1312 #endif
  1313 #ifdef Pack_32
  1314 	if ((y = d1)) {
  1315 		if ((k = lo0bits(&y))) {
  1316 			x[0] = y | z << (32 - k);
  1317 			z >>= k;
  1319 		else
  1320 			x[0] = y;
  1321 #ifndef Sudden_Underflow
  1322 		i =
  1323 #endif
  1324 		    b->wds = (x[1] = z) ? 2 : 1;
  1326 	else {
  1327 		k = lo0bits(&z);
  1328 		x[0] = z;
  1329 #ifndef Sudden_Underflow
  1330 		i =
  1331 #endif
  1332 		    b->wds = 1;
  1333 		k += 32;
  1335 #else
  1336 	if (y = d1) {
  1337 		if (k = lo0bits(&y))
  1338 			if (k >= 16) {
  1339 				x[0] = y | z << 32 - k & 0xffff;
  1340 				x[1] = z >> k - 16 & 0xffff;
  1341 				x[2] = z >> k;
  1342 				i = 2;
  1344 			else {
  1345 				x[0] = y & 0xffff;
  1346 				x[1] = y >> 16 | z << 16 - k & 0xffff;
  1347 				x[2] = z >> k & 0xffff;
  1348 				x[3] = z >> k+16;
  1349 				i = 3;
  1351 		else {
  1352 			x[0] = y & 0xffff;
  1353 			x[1] = y >> 16;
  1354 			x[2] = z & 0xffff;
  1355 			x[3] = z >> 16;
  1356 			i = 3;
  1359 	else {
  1360 #ifdef DEBUG
  1361 		if (!z)
  1362 			Bug("Zero passed to d2b");
  1363 #endif
  1364 		k = lo0bits(&z);
  1365 		if (k >= 16) {
  1366 			x[0] = z;
  1367 			i = 0;
  1369 		else {
  1370 			x[0] = z & 0xffff;
  1371 			x[1] = z >> 16;
  1372 			i = 1;
  1374 		k += 32;
  1376 	while(!x[i])
  1377 		--i;
  1378 	b->wds = i + 1;
  1379 #endif
  1380 #ifndef Sudden_Underflow
  1381 	if (de) {
  1382 #endif
  1383 #ifdef IBM
  1384 		*e = (de - Bias - (P-1) << 2) + k;
  1385 		*bits = 4*P + 8 - k - hi0bits(word0(d) & Frac_mask);
  1386 #else
  1387 		*e = de - Bias - (P-1) + k;
  1388 		*bits = P - k;
  1389 #endif
  1390 #ifndef Sudden_Underflow
  1392 	else {
  1393 		*e = de - Bias - (P-1) + 1 + k;
  1394 #ifdef Pack_32
  1395 		*bits = 32*i - hi0bits(x[i-1]);
  1396 #else
  1397 		*bits = (i+2)*16 - hi0bits(x[i]);
  1398 #endif
  1400 #endif
  1401 	return b;
  1403 #undef d0
  1404 #undef d1
  1406  static double
  1407 ratio
  1408 #ifdef KR_headers
  1409 	(a, b) Bigint *a, *b;
  1410 #else
  1411 	(Bigint *a, Bigint *b)
  1412 #endif
  1414 	U da, db;
  1415 	int k, ka, kb;
  1417 	dval(&da) = b2d(a, &ka);
  1418 	dval(&db) = b2d(b, &kb);
  1419 #ifdef Pack_32
  1420 	k = ka - kb + 32*(a->wds - b->wds);
  1421 #else
  1422 	k = ka - kb + 16*(a->wds - b->wds);
  1423 #endif
  1424 #ifdef IBM
  1425 	if (k > 0) {
  1426 		word0(&da) += (k >> 2)*Exp_msk1;
  1427 		if (k &= 3)
  1428 			dval(&da) *= 1 << k;
  1430 	else {
  1431 		k = -k;
  1432 		word0(&db) += (k >> 2)*Exp_msk1;
  1433 		if (k &= 3)
  1434 			dval(&db) *= 1 << k;
  1436 #else
  1437 	if (k > 0)
  1438 		word0(&da) += k*Exp_msk1;
  1439 	else {
  1440 		k = -k;
  1441 		word0(&db) += k*Exp_msk1;
  1443 #endif
  1444 	return dval(&da) / dval(&db);
  1447  static CONST double
  1448 tens[] = {
  1449 		1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9,
  1450 		1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19,
  1451 		1e20, 1e21, 1e22
  1452 #ifdef VAX
  1453 		, 1e23, 1e24
  1454 #endif
  1455 		};
  1457  static CONST double
  1458 #ifdef IEEE_Arith
  1459 bigtens[] = { 1e16, 1e32, 1e64, 1e128, 1e256 };
  1460 static CONST double tinytens[] = { 1e-16, 1e-32, 1e-64, 1e-128,
  1461 #ifdef Avoid_Underflow
  1462 		9007199254740992.*9007199254740992.e-256
  1463 		/* = 2^106 * 1e-256 */
  1464 #else
  1465 		1e-256
  1466 #endif
  1467 		};
  1468 /* The factor of 2^53 in tinytens[4] helps us avoid setting the underflow */
  1469 /* flag unnecessarily.  It leads to a song and dance at the end of strtod. */
  1470 #define Scale_Bit 0x10
  1471 #define n_bigtens 5
  1472 #else
  1473 #ifdef IBM
  1474 bigtens[] = { 1e16, 1e32, 1e64 };
  1475 static CONST double tinytens[] = { 1e-16, 1e-32, 1e-64 };
  1476 #define n_bigtens 3
  1477 #else
  1478 bigtens[] = { 1e16, 1e32 };
  1479 static CONST double tinytens[] = { 1e-16, 1e-32 };
  1480 #define n_bigtens 2
  1481 #endif
  1482 #endif
  1484 #undef Need_Hexdig
  1485 #ifdef INFNAN_CHECK
  1486 #ifndef No_Hex_NaN
  1487 #define Need_Hexdig
  1488 #endif
  1489 #endif
  1491 #ifndef Need_Hexdig
  1492 #ifndef NO_HEX_FP
  1493 #define Need_Hexdig
  1494 #endif
  1495 #endif
  1497 #ifdef Need_Hexdig /*{*/
  1498 static unsigned char hexdig[256];
  1500  static void
  1501 #ifdef KR_headers
  1502 htinit(h, s, inc) unsigned char *h; unsigned char *s; int inc;
  1503 #else
  1504 htinit(unsigned char *h, unsigned char *s, int inc)
  1505 #endif
  1507 	int i, j;
  1508 	for(i = 0; (j = s[i]) !=0; i++)
  1509 		h[j] = i + inc;
  1512  static void
  1513 #ifdef KR_headers
  1514 hexdig_init()
  1515 #else
  1516 hexdig_init(void)
  1517 #endif
  1519 #define USC (unsigned char *)
  1520 	htinit(hexdig, USC "0123456789", 0x10);
  1521 	htinit(hexdig, USC "abcdef", 0x10 + 10);
  1522 	htinit(hexdig, USC "ABCDEF", 0x10 + 10);
  1524 #endif /* } Need_Hexdig */
  1526 #ifdef INFNAN_CHECK
  1528 #ifndef NAN_WORD0
  1529 #define NAN_WORD0 0x7ff80000
  1530 #endif
  1532 #ifndef NAN_WORD1
  1533 #define NAN_WORD1 0
  1534 #endif
  1536  static int
  1537 match
  1538 #ifdef KR_headers
  1539 	(sp, t) char **sp, *t;
  1540 #else
  1541 	(const char **sp, const char *t)
  1542 #endif
  1544 	int c, d;
  1545 	CONST char *s = *sp;
  1547 	while((d = *t++)) {
  1548 		if ((c = *++s) >= 'A' && c <= 'Z')
  1549 			c += 'a' - 'A';
  1550 		if (c != d)
  1551 			return 0;
  1553 	*sp = s + 1;
  1554 	return 1;
  1557 #ifndef No_Hex_NaN
  1558  static void
  1559 hexnan
  1560 #ifdef KR_headers
  1561 	(rvp, sp) U *rvp; CONST char **sp;
  1562 #else
  1563 	(U *rvp, const char **sp)
  1564 #endif
  1566 	ULong c, x[2];
  1567 	CONST char *s;
  1568 	int c1, havedig, udx0, xshift;
  1570 	if (!hexdig['0'])
  1571 		hexdig_init();
  1572 	x[0] = x[1] = 0;
  1573 	havedig = xshift = 0;
  1574 	udx0 = 1;
  1575 	s = *sp;
  1576 	/* allow optional initial 0x or 0X */
  1577 	while((c = *(CONST unsigned char*)(s+1)) && c <= ' ')
  1578 		++s;
  1579 	if (s[1] == '0' && (s[2] == 'x' || s[2] == 'X'))
  1580 		s += 2;
  1581 	while((c = *(CONST unsigned char*)++s)) {
  1582 		if ((c1 = hexdig[c]))
  1583 			c  = c1 & 0xf;
  1584 		else if (c <= ' ') {
  1585 			if (udx0 && havedig) {
  1586 				udx0 = 0;
  1587 				xshift = 1;
  1589 			continue;
  1591 #ifdef GDTOA_NON_PEDANTIC_NANCHECK
  1592 		else if (/*(*/ c == ')' && havedig) {
  1593 			*sp = s + 1;
  1594 			break;
  1596 		else
  1597 			return;	/* invalid form: don't change *sp */
  1598 #else
  1599 		else {
  1600 			do {
  1601 				if (/*(*/ c == ')') {
  1602 					*sp = s + 1;
  1603 					break;
  1605 				} while((c = *++s));
  1606 			break;
  1608 #endif
  1609 		havedig = 1;
  1610 		if (xshift) {
  1611 			xshift = 0;
  1612 			x[0] = x[1];
  1613 			x[1] = 0;
  1615 		if (udx0)
  1616 			x[0] = (x[0] << 4) | (x[1] >> 28);
  1617 		x[1] = (x[1] << 4) | c;
  1619 	if ((x[0] &= 0xfffff) || x[1]) {
  1620 		word0(rvp) = Exp_mask | x[0];
  1621 		word1(rvp) = x[1];
  1624 #endif /*No_Hex_NaN*/
  1625 #endif /* INFNAN_CHECK */
  1627 #ifdef Pack_32
  1628 #define ULbits 32
  1629 #define kshift 5
  1630 #define kmask 31
  1631 #else
  1632 #define ULbits 16
  1633 #define kshift 4
  1634 #define kmask 15
  1635 #endif
  1637 #if !defined(NO_HEX_FP) || defined(Honor_FLT_ROUNDS) /*{*/
  1638  static Bigint *
  1639 #ifdef KR_headers
  1640 increment(b) Bigint *b;
  1641 #else
  1642 increment(Bigint *b)
  1643 #endif
  1645 	ULong *x, *xe;
  1646 	Bigint *b1;
  1648 	x = b->x;
  1649 	xe = x + b->wds;
  1650 	do {
  1651 		if (*x < (ULong)0xffffffffL) {
  1652 			++*x;
  1653 			return b;
  1655 		*x++ = 0;
  1656 		} while(x < xe);
  1658 		if (b->wds >= b->maxwds) {
  1659 			b1 = Balloc(b->k+1);
  1660 			Bcopy(b1,b);
  1661 			Bfree(b);
  1662 			b = b1;
  1664 		b->x[b->wds++] = 1;
  1666 	return b;
  1669 #endif /*}*/
  1671 #ifndef NO_HEX_FP /*{*/
  1673  static void
  1674 #ifdef KR_headers
  1675 rshift(b, k) Bigint *b; int k;
  1676 #else
  1677 rshift(Bigint *b, int k)
  1678 #endif
  1680 	ULong *x, *x1, *xe, y;
  1681 	int n;
  1683 	x = x1 = b->x;
  1684 	n = k >> kshift;
  1685 	if (n < b->wds) {
  1686 		xe = x + b->wds;
  1687 		x += n;
  1688 		if (k &= kmask) {
  1689 			n = 32 - k;
  1690 			y = *x++ >> k;
  1691 			while(x < xe) {
  1692 				*x1++ = (y | (*x << n)) & 0xffffffff;
  1693 				y = *x++ >> k;
  1695 			if ((*x1 = y) !=0)
  1696 				x1++;
  1698 		else
  1699 			while(x < xe)
  1700 				*x1++ = *x++;
  1702 	if ((b->wds = x1 - b->x) == 0)
  1703 		b->x[0] = 0;
  1706  static ULong
  1707 #ifdef KR_headers
  1708 any_on(b, k) Bigint *b; int k;
  1709 #else
  1710 any_on(Bigint *b, int k)
  1711 #endif
  1713 	int n, nwds;
  1714 	ULong *x, *x0, x1, x2;
  1716 	x = b->x;
  1717 	nwds = b->wds;
  1718 	n = k >> kshift;
  1719 	if (n > nwds)
  1720 		n = nwds;
  1721 	else if (n < nwds && (k &= kmask)) {
  1722 		x1 = x2 = x[n];
  1723 		x1 >>= k;
  1724 		x1 <<= k;
  1725 		if (x1 != x2)
  1726 			return 1;
  1728 	x0 = x;
  1729 	x += n;
  1730 	while(x > x0)
  1731 		if (*--x)
  1732 			return 1;
  1733 	return 0;
  1736 enum {	/* rounding values: same as FLT_ROUNDS */
  1737 	Round_zero = 0,
  1738 	Round_near = 1,
  1739 	Round_up = 2,
  1740 	Round_down = 3
  1741 	};
  1743  void
  1744 #ifdef KR_headers
  1745 gethex(sp, rvp, rounding, sign)
  1746 	CONST char **sp; U *rvp; int rounding, sign;
  1747 #else
  1748 gethex( CONST char **sp, U *rvp, int rounding, int sign)
  1749 #endif
  1751 	Bigint *b;
  1752 	CONST unsigned char *decpt, *s0, *s, *s1;
  1753 	Long e, e1;
  1754 	ULong L, lostbits, *x;
  1755 	int big, denorm, esign, havedig, k, n, nbits, up, zret;
  1756 #ifdef IBM
  1757 	int j;
  1758 #endif
  1759 	enum {
  1760 #ifdef IEEE_Arith /*{{*/
  1761 		emax = 0x7fe - Bias - P + 1,
  1762 		emin = Emin - P + 1
  1763 #else /*}{*/
  1764 		emin = Emin - P,
  1765 #ifdef VAX
  1766 		emax = 0x7ff - Bias - P + 1
  1767 #endif
  1768 #ifdef IBM
  1769 		emax = 0x7f - Bias - P
  1770 #endif
  1771 #endif /*}}*/
  1772 		};
  1773 #ifdef USE_LOCALE
  1774 	int i;
  1775 #ifdef NO_LOCALE_CACHE
  1776 	const unsigned char *decimalpoint = (unsigned char*)
  1777 		localeconv()->decimal_point;
  1778 #else
  1779 	const unsigned char *decimalpoint;
  1780 	static unsigned char *decimalpoint_cache;
  1781 	if (!(s0 = decimalpoint_cache)) {
  1782 		s0 = (unsigned char*)localeconv()->decimal_point;
  1783 		if ((decimalpoint_cache = (unsigned char*)
  1784 				MALLOC(strlen((CONST char*)s0) + 1))) {
  1785 			strcpy((char*)decimalpoint_cache, (CONST char*)s0);
  1786 			s0 = decimalpoint_cache;
  1789 	decimalpoint = s0;
  1790 #endif
  1791 #endif
  1793 	if (!hexdig['0'])
  1794 		hexdig_init();
  1795 	havedig = 0;
  1796 	s0 = *(CONST unsigned char **)sp + 2;
  1797 	while(s0[havedig] == '0')
  1798 		havedig++;
  1799 	s0 += havedig;
  1800 	s = s0;
  1801 	decpt = 0;
  1802 	zret = 0;
  1803 	e = 0;
  1804 	if (hexdig[*s])
  1805 		havedig++;
  1806 	else {
  1807 		zret = 1;
  1808 #ifdef USE_LOCALE
  1809 		for(i = 0; decimalpoint[i]; ++i) {
  1810 			if (s[i] != decimalpoint[i])
  1811 				goto pcheck;
  1813 		decpt = s += i;
  1814 #else
  1815 		if (*s != '.')
  1816 			goto pcheck;
  1817 		decpt = ++s;
  1818 #endif
  1819 		if (!hexdig[*s])
  1820 			goto pcheck;
  1821 		while(*s == '0')
  1822 			s++;
  1823 		if (hexdig[*s])
  1824 			zret = 0;
  1825 		havedig = 1;
  1826 		s0 = s;
  1828 	while(hexdig[*s])
  1829 		s++;
  1830 #ifdef USE_LOCALE
  1831 	if (*s == *decimalpoint && !decpt) {
  1832 		for(i = 1; decimalpoint[i]; ++i) {
  1833 			if (s[i] != decimalpoint[i])
  1834 				goto pcheck;
  1836 		decpt = s += i;
  1837 #else
  1838 	if (*s == '.' && !decpt) {
  1839 		decpt = ++s;
  1840 #endif
  1841 		while(hexdig[*s])
  1842 			s++;
  1843 		}/*}*/
  1844 	if (decpt)
  1845 		e = -(((Long)(s-decpt)) << 2);
  1846  pcheck:
  1847 	s1 = s;
  1848 	big = esign = 0;
  1849 	switch(*s) {
  1850 	  case 'p':
  1851 	  case 'P':
  1852 		switch(*++s) {
  1853 		  case '-':
  1854 			esign = 1;
  1855 			/* no break */
  1856 		  case '+':
  1857 			s++;
  1859 		if ((n = hexdig[*s]) == 0 || n > 0x19) {
  1860 			s = s1;
  1861 			break;
  1863 		e1 = n - 0x10;
  1864 		while((n = hexdig[*++s]) !=0 && n <= 0x19) {
  1865 			if (e1 & 0xf8000000)
  1866 				big = 1;
  1867 			e1 = 10*e1 + n - 0x10;
  1869 		if (esign)
  1870 			e1 = -e1;
  1871 		e += e1;
  1873 	*sp = (char*)s;
  1874 	if (!havedig)
  1875 		*sp = (char*)s0 - 1;
  1876 	if (zret)
  1877 		goto retz1;
  1878 	if (big) {
  1879 		if (esign) {
  1880 #ifdef IEEE_Arith
  1881 			switch(rounding) {
  1882 			  case Round_up:
  1883 				if (sign)
  1884 					break;
  1885 				goto ret_tiny;
  1886 			  case Round_down:
  1887 				if (!sign)
  1888 					break;
  1889 				goto ret_tiny;
  1891 #endif
  1892 			goto retz;
  1893 #ifdef IEEE_Arith
  1894  ret_tiny:
  1895 #ifndef NO_ERRNO
  1896 			errno = ERANGE;
  1897 #endif
  1898 			word0(rvp) = 0;
  1899 			word1(rvp) = 1;
  1900 			return;
  1901 #endif /* IEEE_Arith */
  1903 		switch(rounding) {
  1904 		  case Round_near:
  1905 			goto ovfl1;
  1906 		  case Round_up:
  1907 			if (!sign)
  1908 				goto ovfl1;
  1909 			goto ret_big;
  1910 		  case Round_down:
  1911 			if (sign)
  1912 				goto ovfl1;
  1913 			goto ret_big;
  1915  ret_big:
  1916 		word0(rvp) = Big0;
  1917 		word1(rvp) = Big1;
  1918 		return;
  1920 	n = s1 - s0 - 1;
  1921 	for(k = 0; n > (1 << (kshift-2)) - 1; n >>= 1)
  1922 		k++;
  1923 	b = Balloc(k);
  1924 	x = b->x;
  1925 	n = 0;
  1926 	L = 0;
  1927 #ifdef USE_LOCALE
  1928 	for(i = 0; decimalpoint[i+1]; ++i);
  1929 #endif
  1930 	while(s1 > s0) {
  1931 #ifdef USE_LOCALE
  1932 		if (*--s1 == decimalpoint[i]) {
  1933 			s1 -= i;
  1934 			continue;
  1936 #else
  1937 		if (*--s1 == '.')
  1938 			continue;
  1939 #endif
  1940 		if (n == ULbits) {
  1941 			*x++ = L;
  1942 			L = 0;
  1943 			n = 0;
  1945 		L |= (hexdig[*s1] & 0x0f) << n;
  1946 		n += 4;
  1948 	*x++ = L;
  1949 	b->wds = n = x - b->x;
  1950 	n = ULbits*n - hi0bits(L);
  1951 	nbits = Nbits;
  1952 	lostbits = 0;
  1953 	x = b->x;
  1954 	if (n > nbits) {
  1955 		n -= nbits;
  1956 		if (any_on(b,n)) {
  1957 			lostbits = 1;
  1958 			k = n - 1;
  1959 			if (x[k>>kshift] & 1 << (k & kmask)) {
  1960 				lostbits = 2;
  1961 				if (k > 0 && any_on(b,k))
  1962 					lostbits = 3;
  1965 		rshift(b, n);
  1966 		e += n;
  1968 	else if (n < nbits) {
  1969 		n = nbits - n;
  1970 		b = lshift(b, n);
  1971 		e -= n;
  1972 		x = b->x;
  1974 	if (e > Emax) {
  1975  ovfl:
  1976 		Bfree(b);
  1977  ovfl1:
  1978 #ifndef NO_ERRNO
  1979 		errno = ERANGE;
  1980 #endif
  1981 		word0(rvp) = Exp_mask;
  1982 		word1(rvp) = 0;
  1983 		return;
  1985 	denorm = 0;
  1986 	if (e < emin) {
  1987 		denorm = 1;
  1988 		n = emin - e;
  1989 		if (n >= nbits) {
  1990 #ifdef IEEE_Arith /*{*/
  1991 			switch (rounding) {
  1992 			  case Round_near:
  1993 				if (n == nbits && (n < 2 || any_on(b,n-1)))
  1994 					goto ret_tiny;
  1995 				break;
  1996 			  case Round_up:
  1997 				if (!sign)
  1998 					goto ret_tiny;
  1999 				break;
  2000 			  case Round_down:
  2001 				if (sign)
  2002 					goto ret_tiny;
  2004 #endif /* } IEEE_Arith */
  2005 			Bfree(b);
  2006  retz:
  2007 #ifndef NO_ERRNO
  2008 			errno = ERANGE;
  2009 #endif
  2010  retz1:
  2011 			rvp->d = 0.;
  2012 			return;
  2014 		k = n - 1;
  2015 		if (lostbits)
  2016 			lostbits = 1;
  2017 		else if (k > 0)
  2018 			lostbits = any_on(b,k);
  2019 		if (x[k>>kshift] & 1 << (k & kmask))
  2020 			lostbits |= 2;
  2021 		nbits -= n;
  2022 		rshift(b,n);
  2023 		e = emin;
  2025 	if (lostbits) {
  2026 		up = 0;
  2027 		switch(rounding) {
  2028 		  case Round_zero:
  2029 			break;
  2030 		  case Round_near:
  2031 			if (lostbits & 2
  2032 			 && (lostbits & 1) | (x[0] & 1))
  2033 				up = 1;
  2034 			break;
  2035 		  case Round_up:
  2036 			up = 1 - sign;
  2037 			break;
  2038 		  case Round_down:
  2039 			up = sign;
  2041 		if (up) {
  2042 			k = b->wds;
  2043 			b = increment(b);
  2044 			x = b->x;
  2045 			if (denorm) {
  2046 #if 0
  2047 				if (nbits == Nbits - 1
  2048 				 && x[nbits >> kshift] & 1 << (nbits & kmask))
  2049 					denorm = 0; /* not currently used */
  2050 #endif
  2052 			else if (b->wds > k
  2053 			 || ((n = nbits & kmask) !=0
  2054 			     && hi0bits(x[k-1]) < 32-n)) {
  2055 				rshift(b,1);
  2056 				if (++e > Emax)
  2057 					goto ovfl;
  2061 #ifdef IEEE_Arith
  2062 	if (denorm)
  2063 		word0(rvp) = b->wds > 1 ? b->x[1] & ~0x100000 : 0;
  2064 	else
  2065 		word0(rvp) = (b->x[1] & ~0x100000) | ((e + 0x3ff + 52) << 20);
  2066 	word1(rvp) = b->x[0];
  2067 #endif
  2068 #ifdef IBM
  2069 	if ((j = e & 3)) {
  2070 		k = b->x[0] & ((1 << j) - 1);
  2071 		rshift(b,j);
  2072 		if (k) {
  2073 			switch(rounding) {
  2074 			  case Round_up:
  2075 				if (!sign)
  2076 					increment(b);
  2077 				break;
  2078 			  case Round_down:
  2079 				if (sign)
  2080 					increment(b);
  2081 				break;
  2082 			  case Round_near:
  2083 				j = 1 << (j-1);
  2084 				if (k & j && ((k & (j-1)) | lostbits))
  2085 					increment(b);
  2089 	e >>= 2;
  2090 	word0(rvp) = b->x[1] | ((e + 65 + 13) << 24);
  2091 	word1(rvp) = b->x[0];
  2092 #endif
  2093 #ifdef VAX
  2094 	/* The next two lines ignore swap of low- and high-order 2 bytes. */
  2095 	/* word0(rvp) = (b->x[1] & ~0x800000) | ((e + 129 + 55) << 23); */
  2096 	/* word1(rvp) = b->x[0]; */
  2097 	word0(rvp) = ((b->x[1] & ~0x800000) >> 16) | ((e + 129 + 55) << 7) | (b->x[1] << 16);
  2098 	word1(rvp) = (b->x[0] >> 16) | (b->x[0] << 16);
  2099 #endif
  2100 	Bfree(b);
  2102 #endif /*!NO_HEX_FP}*/
  2104  static int
  2105 #ifdef KR_headers
  2106 dshift(b, p2) Bigint *b; int p2;
  2107 #else
  2108 dshift(Bigint *b, int p2)
  2109 #endif
  2111 	int rv = hi0bits(b->x[b->wds-1]) - 4;
  2112 	if (p2 > 0)
  2113 		rv -= p2;
  2114 	return rv & kmask;
  2117  static int
  2118 quorem
  2119 #ifdef KR_headers
  2120 	(b, S) Bigint *b, *S;
  2121 #else
  2122 	(Bigint *b, Bigint *S)
  2123 #endif
  2125 	int n;
  2126 	ULong *bx, *bxe, q, *sx, *sxe;
  2127 #ifdef ULLong
  2128 	ULLong borrow, carry, y, ys;
  2129 #else
  2130 	ULong borrow, carry, y, ys;
  2131 #ifdef Pack_32
  2132 	ULong si, z, zs;
  2133 #endif
  2134 #endif
  2136 	n = S->wds;
  2137 #ifdef DEBUG
  2138 	/*debug*/ if (b->wds > n)
  2139 	/*debug*/	Bug("oversize b in quorem");
  2140 #endif
  2141 	if (b->wds < n)
  2142 		return 0;
  2143 	sx = S->x;
  2144 	sxe = sx + --n;
  2145 	bx = b->x;
  2146 	bxe = bx + n;
  2147 	q = *bxe / (*sxe + 1);	/* ensure q <= true quotient */
  2148 #ifdef DEBUG
  2149 #ifdef NO_STRTOD_BIGCOMP
  2150 	/*debug*/ if (q > 9)
  2151 #else
  2152 	/* An oversized q is possible when quorem is called from bigcomp and */
  2153 	/* the input is near, e.g., twice the smallest denormalized number. */
  2154 	/*debug*/ if (q > 15)
  2155 #endif
  2156 	/*debug*/	Bug("oversized quotient in quorem");
  2157 #endif
  2158 	if (q) {
  2159 		borrow = 0;
  2160 		carry = 0;
  2161 		do {
  2162 #ifdef ULLong
  2163 			ys = *sx++ * (ULLong)q + carry;
  2164 			carry = ys >> 32;
  2165 			y = *bx - (ys & FFFFFFFF) - borrow;
  2166 			borrow = y >> 32 & (ULong)1;
  2167 			*bx++ = y & FFFFFFFF;
  2168 #else
  2169 #ifdef Pack_32
  2170 			si = *sx++;
  2171 			ys = (si & 0xffff) * q + carry;
  2172 			zs = (si >> 16) * q + (ys >> 16);
  2173 			carry = zs >> 16;
  2174 			y = (*bx & 0xffff) - (ys & 0xffff) - borrow;
  2175 			borrow = (y & 0x10000) >> 16;
  2176 			z = (*bx >> 16) - (zs & 0xffff) - borrow;
  2177 			borrow = (z & 0x10000) >> 16;
  2178 			Storeinc(bx, z, y);
  2179 #else
  2180 			ys = *sx++ * q + carry;
  2181 			carry = ys >> 16;
  2182 			y = *bx - (ys & 0xffff) - borrow;
  2183 			borrow = (y & 0x10000) >> 16;
  2184 			*bx++ = y & 0xffff;
  2185 #endif
  2186 #endif
  2188 			while(sx <= sxe);
  2189 		if (!*bxe) {
  2190 			bx = b->x;
  2191 			while(--bxe > bx && !*bxe)
  2192 				--n;
  2193 			b->wds = n;
  2196 	if (cmp(b, S) >= 0) {
  2197 		q++;
  2198 		borrow = 0;
  2199 		carry = 0;
  2200 		bx = b->x;
  2201 		sx = S->x;
  2202 		do {
  2203 #ifdef ULLong
  2204 			ys = *sx++ + carry;
  2205 			carry = ys >> 32;
  2206 			y = *bx - (ys & FFFFFFFF) - borrow;
  2207 			borrow = y >> 32 & (ULong)1;
  2208 			*bx++ = y & FFFFFFFF;
  2209 #else
  2210 #ifdef Pack_32
  2211 			si = *sx++;
  2212 			ys = (si & 0xffff) + carry;
  2213 			zs = (si >> 16) + (ys >> 16);
  2214 			carry = zs >> 16;
  2215 			y = (*bx & 0xffff) - (ys & 0xffff) - borrow;
  2216 			borrow = (y & 0x10000) >> 16;
  2217 			z = (*bx >> 16) - (zs & 0xffff) - borrow;
  2218 			borrow = (z & 0x10000) >> 16;
  2219 			Storeinc(bx, z, y);
  2220 #else
  2221 			ys = *sx++ + carry;
  2222 			carry = ys >> 16;
  2223 			y = *bx - (ys & 0xffff) - borrow;
  2224 			borrow = (y & 0x10000) >> 16;
  2225 			*bx++ = y & 0xffff;
  2226 #endif
  2227 #endif
  2229 			while(sx <= sxe);
  2230 		bx = b->x;
  2231 		bxe = bx + n;
  2232 		if (!*bxe) {
  2233 			while(--bxe > bx && !*bxe)
  2234 				--n;
  2235 			b->wds = n;
  2238 	return q;
  2241 #if defined(Avoid_Underflow) || !defined(NO_STRTOD_BIGCOMP) /*{*/
  2242  static double
  2243 sulp
  2244 #ifdef KR_headers
  2245 	(x, bc) U *x; BCinfo *bc;
  2246 #else
  2247 	(U *x, BCinfo *bc)
  2248 #endif
  2250 	U u;
  2251 	double rv;
  2252 	int i;
  2254 	rv = ulp(x);
  2255 	if (!bc->scale || (i = 2*P + 1 - ((word0(x) & Exp_mask) >> Exp_shift)) <= 0)
  2256 		return rv; /* Is there an example where i <= 0 ? */
  2257 	word0(&u) = Exp_1 + (i << Exp_shift);
  2258 	word1(&u) = 0;
  2259 	return rv * u.d;
  2261 #endif /*}*/
  2263 #ifndef NO_STRTOD_BIGCOMP
  2264  static void
  2265 bigcomp
  2266 #ifdef KR_headers
  2267 	(rv, s0, bc)
  2268 	U *rv; CONST char *s0; BCinfo *bc;
  2269 #else
  2270 	(U *rv, const char *s0, BCinfo *bc)
  2271 #endif
  2273 	Bigint *b, *d;
  2274 	int b2, bbits, d2, dd, dig, dsign, i, j, nd, nd0, p2, p5, speccase;
  2276 	dsign = bc->dsign;
  2277 	nd = bc->nd;
  2278 	nd0 = bc->nd0;
  2279 	p5 = nd + bc->e0 - 1;
  2280 	speccase = 0;
  2281 #ifndef Sudden_Underflow
  2282 	if (rv->d == 0.) {	/* special case: value near underflow-to-zero */
  2283 				/* threshold was rounded to zero */
  2284 		b = i2b(1);
  2285 		p2 = Emin - P + 1;
  2286 		bbits = 1;
  2287 #ifdef Avoid_Underflow
  2288 		word0(rv) = (P+2) << Exp_shift;
  2289 #else
  2290 		word1(rv) = 1;
  2291 #endif
  2292 		i = 0;
  2293 #ifdef Honor_FLT_ROUNDS
  2294 		if (bc->rounding == 1)
  2295 #endif
  2297 			speccase = 1;
  2298 			--p2;
  2299 			dsign = 0;
  2300 			goto have_i;
  2303 	else
  2304 #endif
  2305 		b = d2b(rv, &p2, &bbits);
  2306 #ifdef Avoid_Underflow
  2307 	p2 -= bc->scale;
  2308 #endif
  2309 	/* floor(log2(rv)) == bbits - 1 + p2 */
  2310 	/* Check for denormal case. */
  2311 	i = P - bbits;
  2312 	if (i > (j = P - Emin - 1 + p2)) {
  2313 #ifdef Sudden_Underflow
  2314 		Bfree(b);
  2315 		b = i2b(1);
  2316 		p2 = Emin;
  2317 		i = P - 1;
  2318 #ifdef Avoid_Underflow
  2319 		word0(rv) = (1 + bc->scale) << Exp_shift;
  2320 #else
  2321 		word0(rv) = Exp_msk1;
  2322 #endif
  2323 		word1(rv) = 0;
  2324 #else
  2325 		i = j;
  2326 #endif
  2328 #ifdef Honor_FLT_ROUNDS
  2329 	if (bc->rounding != 1) {
  2330 		if (i > 0)
  2331 			b = lshift(b, i);
  2332 		if (dsign)
  2333 			b = increment(b);
  2335 	else
  2336 #endif
  2338 		b = lshift(b, ++i);
  2339 		b->x[0] |= 1;
  2341 #ifndef Sudden_Underflow
  2342  have_i:
  2343 #endif
  2344 	p2 -= p5 + i;
  2345 	d = i2b(1);
  2346 	/* Arrange for convenient computation of quotients:
  2347 	 * shift left if necessary so divisor has 4 leading 0 bits.
  2348 	 */
  2349 	if (p5 > 0)
  2350 		d = pow5mult(d, p5);
  2351 	else if (p5 < 0)
  2352 		b = pow5mult(b, -p5);
  2353 	if (p2 > 0) {
  2354 		b2 = p2;
  2355 		d2 = 0;
  2357 	else {
  2358 		b2 = 0;
  2359 		d2 = -p2;
  2361 	i = dshift(d, d2);
  2362 	if ((b2 += i) > 0)
  2363 		b = lshift(b, b2);
  2364 	if ((d2 += i) > 0)
  2365 		d = lshift(d, d2);
  2367 	/* Now b/d = exactly half-way between the two floating-point values */
  2368 	/* on either side of the input string.  Compute first digit of b/d. */
  2370 	if (!(dig = quorem(b,d))) {
  2371 		b = multadd(b, 10, 0);	/* very unlikely */
  2372 		dig = quorem(b,d);
  2375 	/* Compare b/d with s0 */
  2377 	for(i = 0; i < nd0; ) {
  2378 		if ((dd = s0[i++] - '0' - dig))
  2379 			goto ret;
  2380 		if (!b->x[0] && b->wds == 1) {
  2381 			if (i < nd)
  2382 				dd = 1;
  2383 			goto ret;
  2385 		b = multadd(b, 10, 0);
  2386 		dig = quorem(b,d);
  2388 	for(j = bc->dp1; i++ < nd;) {
  2389 		if ((dd = s0[j++] - '0' - dig))
  2390 			goto ret;
  2391 		if (!b->x[0] && b->wds == 1) {
  2392 			if (i < nd)
  2393 				dd = 1;
  2394 			goto ret;
  2396 		b = multadd(b, 10, 0);
  2397 		dig = quorem(b,d);
  2399 	if (b->x[0] || b->wds > 1 || dig > 0)
  2400 		dd = -1;
  2401  ret:
  2402 	Bfree(b);
  2403 	Bfree(d);
  2404 #ifdef Honor_FLT_ROUNDS
  2405 	if (bc->rounding != 1) {
  2406 		if (dd < 0) {
  2407 			if (bc->rounding == 0) {
  2408 				if (!dsign)
  2409 					goto retlow1;
  2411 			else if (dsign)
  2412 				goto rethi1;
  2414 		else if (dd > 0) {
  2415 			if (bc->rounding == 0) {
  2416 				if (dsign)
  2417 					goto rethi1;
  2418 				goto ret1;
  2420 			if (!dsign)
  2421 				goto rethi1;
  2422 			dval(rv) += 2.*sulp(rv,bc);
  2424 		else {
  2425 			bc->inexact = 0;
  2426 			if (dsign)
  2427 				goto rethi1;
  2430 	else
  2431 #endif
  2432 	if (speccase) {
  2433 		if (dd <= 0)
  2434 			rv->d = 0.;
  2436 	else if (dd < 0) {
  2437 		if (!dsign)	/* does not happen for round-near */
  2438 retlow1:
  2439 			dval(rv) -= sulp(rv,bc);
  2441 	else if (dd > 0) {
  2442 		if (dsign) {
  2443  rethi1:
  2444 			dval(rv) += sulp(rv,bc);
  2447 	else {
  2448 		/* Exact half-way case:  apply round-even rule. */
  2449 		if ((j = ((word0(rv) & Exp_mask) >> Exp_shift) - bc->scale) <= 0) {
  2450 			i = 1 - j;
  2451 			if (i <= 31) {
  2452 				if (word1(rv) & (0x1 << i))
  2453 					goto odd;
  2455 			else if (word0(rv) & (0x1 << (i-32)))
  2456 				goto odd;
  2458 		else if (word1(rv) & 1) {
  2459  odd:
  2460 			if (dsign)
  2461 				goto rethi1;
  2462 			goto retlow1;
  2466 #ifdef Honor_FLT_ROUNDS
  2467  ret1:
  2468 #endif
  2469 	return;
  2471 #endif /* NO_STRTOD_BIGCOMP */
  2473  double
  2474 strtod
  2475 #ifdef KR_headers
  2476 	(s00, se) CONST char *s00; char **se;
  2477 #else
  2478 	(const char *s00, char **se)
  2479 #endif
  2481 	int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, e, e1;
  2482 	int esign, i, j, k, nd, nd0, nf, nz, nz0, nz1, sign;
  2483 	CONST char *s, *s0, *s1;
  2484 	double aadj, aadj1;
  2485 	Long L;
  2486 	U aadj2, adj, rv, rv0;
  2487 	ULong y, z;
  2488 	BCinfo bc;
  2489 	Bigint *bb, *bb1, *bd, *bd0, *bs, *delta;
  2490 #ifdef Avoid_Underflow
  2491 	ULong Lsb, Lsb1;
  2492 #endif
  2493 #ifdef SET_INEXACT
  2494 	int oldinexact;
  2495 #endif
  2496 #ifndef NO_STRTOD_BIGCOMP
  2497 	int req_bigcomp = 0;
  2498 #endif
  2499 #ifdef Honor_FLT_ROUNDS /*{*/
  2500 #ifdef Trust_FLT_ROUNDS /*{{ only define this if FLT_ROUNDS really works! */
  2501 	bc.rounding = Flt_Rounds;
  2502 #else /*}{*/
  2503 	bc.rounding = 1;
  2504 	switch(fegetround()) {
  2505 	  case FE_TOWARDZERO:	bc.rounding = 0; break;
  2506 	  case FE_UPWARD:	bc.rounding = 2; break;
  2507 	  case FE_DOWNWARD:	bc.rounding = 3;
  2509 #endif /*}}*/
  2510 #endif /*}*/
  2511 #ifdef USE_LOCALE
  2512 	CONST char *s2;
  2513 #endif
  2515 	sign = nz0 = nz1 = nz = bc.dplen = bc.uflchk = 0;
  2516 	dval(&rv) = 0.;
  2517 	for(s = s00;;s++) switch(*s) {
  2518 		case '-':
  2519 			sign = 1;
  2520 			/* no break */
  2521 		case '+':
  2522 			if (*++s)
  2523 				goto break2;
  2524 			/* no break */
  2525 		case 0:
  2526 			goto ret0;
  2527 		case '\t':
  2528 		case '\n':
  2529 		case '\v':
  2530 		case '\f':
  2531 		case '\r':
  2532 		case ' ':
  2533 			continue;
  2534 		default:
  2535 			goto break2;
  2537  break2:
  2538 	if (*s == '0') {
  2539 #ifndef NO_HEX_FP /*{*/
  2540 		switch(s[1]) {
  2541 		  case 'x':
  2542 		  case 'X':
  2543 #ifdef Honor_FLT_ROUNDS
  2544 			gethex(&s, &rv, bc.rounding, sign);
  2545 #else
  2546 			gethex(&s, &rv, 1, sign);
  2547 #endif
  2548 			goto ret;
  2550 #endif /*}*/
  2551 		nz0 = 1;
  2552 		while(*++s == '0') ;
  2553 		if (!*s)
  2554 			goto ret;
  2556 	s0 = s;
  2557 	y = z = 0;
  2558 	for(nd = nf = 0; (c = *s) >= '0' && c <= '9'; nd++, s++)
  2559 		if (nd < 9)
  2560 			y = 10*y + c - '0';
  2561 		else if (nd < 16)
  2562 			z = 10*z + c - '0';
  2563 	nd0 = nd;
  2564 	bc.dp0 = bc.dp1 = s - s0;
  2565 	for(s1 = s; s1 > s0 && *--s1 == '0'; )
  2566 		++nz1;
  2567 #ifdef USE_LOCALE
  2568 	s1 = localeconv()->decimal_point;
  2569 	if (c == *s1) {
  2570 		c = '.';
  2571 		if (*++s1) {
  2572 			s2 = s;
  2573 			for(;;) {
  2574 				if (*++s2 != *s1) {
  2575 					c = 0;
  2576 					break;
  2578 				if (!*++s1) {
  2579 					s = s2;
  2580 					break;
  2585 #endif
  2586 	if (c == '.') {
  2587 		c = *++s;
  2588 		bc.dp1 = s - s0;
  2589 		bc.dplen = bc.dp1 - bc.dp0;
  2590 		if (!nd) {
  2591 			for(; c == '0'; c = *++s)
  2592 				nz++;
  2593 			if (c > '0' && c <= '9') {
  2594 				bc.dp0 = s0 - s;
  2595 				bc.dp1 = bc.dp0 + bc.dplen;
  2596 				s0 = s;
  2597 				nf += nz;
  2598 				nz = 0;
  2599 				goto have_dig;
  2601 			goto dig_done;
  2603 		for(; c >= '0' && c <= '9'; c = *++s) {
  2604  have_dig:
  2605 			nz++;
  2606 			if (c -= '0') {
  2607 				nf += nz;
  2608 				for(i = 1; i < nz; i++)
  2609 					if (nd++ < 9)
  2610 						y *= 10;
  2611 					else if (nd <= DBL_DIG + 1)
  2612 						z *= 10;
  2613 				if (nd++ < 9)
  2614 					y = 10*y + c;
  2615 				else if (nd <= DBL_DIG + 1)
  2616 					z = 10*z + c;
  2617 				nz = nz1 = 0;
  2621  dig_done:
  2622 	e = 0;
  2623 	if (c == 'e' || c == 'E') {
  2624 		if (!nd && !nz && !nz0) {
  2625 			goto ret0;
  2627 		s00 = s;
  2628 		esign = 0;
  2629 		switch(c = *++s) {
  2630 			case '-':
  2631 				esign = 1;
  2632 			case '+':
  2633 				c = *++s;
  2635 		if (c >= '0' && c <= '9') {
  2636 			while(c == '0')
  2637 				c = *++s;
  2638 			if (c > '0' && c <= '9') {
  2639 				L = c - '0';
  2640 				s1 = s;
  2641 				while((c = *++s) >= '0' && c <= '9')
  2642 					L = 10*L + c - '0';
  2643 				if (s - s1 > 8 || L > 19999)
  2644 					/* Avoid confusion from exponents
  2645 					 * so large that e might overflow.
  2646 					 */
  2647 					e = 19999; /* safe for 16 bit ints */
  2648 				else
  2649 					e = (int)L;
  2650 				if (esign)
  2651 					e = -e;
  2653 			else
  2654 				e = 0;
  2656 		else
  2657 			s = s00;
  2659 	if (!nd) {
  2660 		if (!nz && !nz0) {
  2661 #ifdef INFNAN_CHECK
  2662 			/* Check for Nan and Infinity */
  2663 			if (!bc.dplen)
  2664 			 switch(c) {
  2665 			  case 'i':
  2666 			  case 'I':
  2667 				if (match(&s,"nf")) {
  2668 					--s;
  2669 					if (!match(&s,"inity"))
  2670 						++s;
  2671 					word0(&rv) = 0x7ff00000;
  2672 					word1(&rv) = 0;
  2673 					goto ret;
  2675 				break;
  2676 			  case 'n':
  2677 			  case 'N':
  2678 				if (match(&s, "an")) {
  2679 					word0(&rv) = NAN_WORD0;
  2680 					word1(&rv) = NAN_WORD1;
  2681 #ifndef No_Hex_NaN
  2682 					if (*s == '(') /*)*/
  2683 						hexnan(&rv, &s);
  2684 #endif
  2685 					goto ret;
  2688 #endif /* INFNAN_CHECK */
  2689  ret0:
  2690 			s = s00;
  2691 			sign = 0;
  2693 		goto ret;
  2695 	bc.e0 = e1 = e -= nf;
  2697 	/* Now we have nd0 digits, starting at s0, followed by a
  2698 	 * decimal point, followed by nd-nd0 digits.  The number we're
  2699 	 * after is the integer represented by those digits times
  2700 	 * 10**e */
  2702 	if (!nd0)
  2703 		nd0 = nd;
  2704 	k = nd < DBL_DIG + 1 ? nd : DBL_DIG + 1;
  2705 	dval(&rv) = y;
  2706 	if (k > 9) {
  2707 #ifdef SET_INEXACT
  2708 		if (k > DBL_DIG)
  2709 			oldinexact = get_inexact();
  2710 #endif
  2711 		dval(&rv) = tens[k - 9] * dval(&rv) + z;
  2713 	bd0 = 0;
  2714 	if (nd <= DBL_DIG
  2715 #ifndef RND_PRODQUOT
  2716 #ifndef Honor_FLT_ROUNDS
  2717 		&& Flt_Rounds == 1
  2718 #endif
  2719 #endif
  2720 			) {
  2721 		if (!e)
  2722 			goto ret;
  2723 #ifndef ROUND_BIASED_without_Round_Up
  2724 		if (e > 0) {
  2725 			if (e <= Ten_pmax) {
  2726 #ifdef VAX
  2727 				goto vax_ovfl_check;
  2728 #else
  2729 #ifdef Honor_FLT_ROUNDS
  2730 				/* round correctly FLT_ROUNDS = 2 or 3 */
  2731 				if (sign) {
  2732 					rv.d = -rv.d;
  2733 					sign = 0;
  2735 #endif
  2736 				/* rv = */ rounded_product(dval(&rv), tens[e]);
  2737 				goto ret;
  2738 #endif
  2740 			i = DBL_DIG - nd;
  2741 			if (e <= Ten_pmax + i) {
  2742 				/* A fancier test would sometimes let us do
  2743 				 * this for larger i values.
  2744 				 */
  2745 #ifdef Honor_FLT_ROUNDS
  2746 				/* round correctly FLT_ROUNDS = 2 or 3 */
  2747 				if (sign) {
  2748 					rv.d = -rv.d;
  2749 					sign = 0;
  2751 #endif
  2752 				e -= i;
  2753 				dval(&rv) *= tens[i];
  2754 #ifdef VAX
  2755 				/* VAX exponent range is so narrow we must
  2756 				 * worry about overflow here...
  2757 				 */
  2758  vax_ovfl_check:
  2759 				word0(&rv) -= P*Exp_msk1;
  2760 				/* rv = */ rounded_product(dval(&rv), tens[e]);
  2761 				if ((word0(&rv) & Exp_mask)
  2762 				 > Exp_msk1*(DBL_MAX_EXP+Bias-1-P))
  2763 					goto ovfl;
  2764 				word0(&rv) += P*Exp_msk1;
  2765 #else
  2766 				/* rv = */ rounded_product(dval(&rv), tens[e]);
  2767 #endif
  2768 				goto ret;
  2771 #ifndef Inaccurate_Divide
  2772 		else if (e >= -Ten_pmax) {
  2773 #ifdef Honor_FLT_ROUNDS
  2774 			/* round correctly FLT_ROUNDS = 2 or 3 */
  2775 			if (sign) {
  2776 				rv.d = -rv.d;
  2777 				sign = 0;
  2779 #endif
  2780 			/* rv = */ rounded_quotient(dval(&rv), tens[-e]);
  2781 			goto ret;
  2783 #endif
  2784 #endif /* ROUND_BIASED_without_Round_Up */
  2786 	e1 += nd - k;
  2788 #ifdef IEEE_Arith
  2789 #ifdef SET_INEXACT
  2790 	bc.inexact = 1;
  2791 	if (k <= DBL_DIG)
  2792 		oldinexact = get_inexact();
  2793 #endif
  2794 #ifdef Avoid_Underflow
  2795 	bc.scale = 0;
  2796 #endif
  2797 #ifdef Honor_FLT_ROUNDS
  2798 	if (bc.rounding >= 2) {
  2799 		if (sign)
  2800 			bc.rounding = bc.rounding == 2 ? 0 : 2;
  2801 		else
  2802 			if (bc.rounding != 2)
  2803 				bc.rounding = 0;
  2805 #endif
  2806 #endif /*IEEE_Arith*/
  2808 	/* Get starting approximation = rv * 10**e1 */
  2810 	if (e1 > 0) {
  2811 		if ((i = e1 & 15))
  2812 			dval(&rv) *= tens[i];
  2813 		if (e1 &= ~15) {
  2814 			if (e1 > DBL_MAX_10_EXP) {
  2815  ovfl:
  2816 				/* Can't trust HUGE_VAL */
  2817 #ifdef IEEE_Arith
  2818 #ifdef Honor_FLT_ROUNDS
  2819 				switch(bc.rounding) {
  2820 				  case 0: /* toward 0 */
  2821 				  case 3: /* toward -infinity */
  2822 					word0(&rv) = Big0;
  2823 					word1(&rv) = Big1;
  2824 					break;
  2825 				  default:
  2826 					word0(&rv) = Exp_mask;
  2827 					word1(&rv) = 0;
  2829 #else /*Honor_FLT_ROUNDS*/
  2830 				word0(&rv) = Exp_mask;
  2831 				word1(&rv) = 0;
  2832 #endif /*Honor_FLT_ROUNDS*/
  2833 #ifdef SET_INEXACT
  2834 				/* set overflow bit */
  2835 				dval(&rv0) = 1e300;
  2836 				dval(&rv0) *= dval(&rv0);
  2837 #endif
  2838 #else /*IEEE_Arith*/
  2839 				word0(&rv) = Big0;
  2840 				word1(&rv) = Big1;
  2841 #endif /*IEEE_Arith*/
  2842  range_err:
  2843 				if (bd0) {
  2844 					Bfree(bb);
  2845 					Bfree(bd);
  2846 					Bfree(bs);
  2847 					Bfree(bd0);
  2848 					Bfree(delta);
  2850 #ifndef NO_ERRNO
  2851 				errno = ERANGE;
  2852 #endif
  2853 				goto ret;
  2855 			e1 >>= 4;
  2856 			for(j = 0; e1 > 1; j++, e1 >>= 1)
  2857 				if (e1 & 1)
  2858 					dval(&rv) *= bigtens[j];
  2859 		/* The last multiplication could overflow. */
  2860 			word0(&rv) -= P*Exp_msk1;
  2861 			dval(&rv) *= bigtens[j];
  2862 			if ((z = word0(&rv) & Exp_mask)
  2863 			 > Exp_msk1*(DBL_MAX_EXP+Bias-P))
  2864 				goto ovfl;
  2865 			if (z > Exp_msk1*(DBL_MAX_EXP+Bias-1-P)) {
  2866 				/* set to largest number */
  2867 				/* (Can't trust DBL_MAX) */
  2868 				word0(&rv) = Big0;
  2869 				word1(&rv) = Big1;
  2871 			else
  2872 				word0(&rv) += P*Exp_msk1;
  2875 	else if (e1 < 0) {
  2876 		e1 = -e1;
  2877 		if ((i = e1 & 15))
  2878 			dval(&rv) /= tens[i];
  2879 		if (e1 >>= 4) {
  2880 			if (e1 >= 1 << n_bigtens)
  2881 				goto undfl;
  2882 #ifdef Avoid_Underflow
  2883 			if (e1 & Scale_Bit)
  2884 				bc.scale = 2*P;
  2885 			for(j = 0; e1 > 0; j++, e1 >>= 1)
  2886 				if (e1 & 1)
  2887 					dval(&rv) *= tinytens[j];
  2888 			if (bc.scale && (j = 2*P + 1 - ((word0(&rv) & Exp_mask)
  2889 						>> Exp_shift)) > 0) {
  2890 				/* scaled rv is denormal; clear j low bits */
  2891 				if (j >= 32) {
  2892 					if (j > 54)
  2893 						goto undfl;
  2894 					word1(&rv) = 0;
  2895 					if (j >= 53)
  2896 					 word0(&rv) = (P+2)*Exp_msk1;
  2897 					else
  2898 					 word0(&rv) &= 0xffffffff << (j-32);
  2900 				else
  2901 					word1(&rv) &= 0xffffffff << j;
  2903 #else
  2904 			for(j = 0; e1 > 1; j++, e1 >>= 1)
  2905 				if (e1 & 1)
  2906 					dval(&rv) *= tinytens[j];
  2907 			/* The last multiplication could underflow. */
  2908 			dval(&rv0) = dval(&rv);
  2909 			dval(&rv) *= tinytens[j];
  2910 			if (!dval(&rv)) {
  2911 				dval(&rv) = 2.*dval(&rv0);
  2912 				dval(&rv) *= tinytens[j];
  2913 #endif
  2914 				if (!dval(&rv)) {
  2915  undfl:
  2916 					dval(&rv) = 0.;
  2917 					goto range_err;
  2919 #ifndef Avoid_Underflow
  2920 				word0(&rv) = Tiny0;
  2921 				word1(&rv) = Tiny1;
  2922 				/* The refinement below will clean
  2923 				 * this approximation up.
  2924 				 */
  2926 #endif
  2930 	/* Now the hard part -- adjusting rv to the correct value.*/
  2932 	/* Put digits into bd: true value = bd * 10^e */
  2934 	bc.nd = nd - nz1;
  2935 #ifndef NO_STRTOD_BIGCOMP
  2936 	bc.nd0 = nd0;	/* Only needed if nd > strtod_diglim, but done here */
  2937 			/* to silence an erroneous warning about bc.nd0 */
  2938 			/* possibly not being initialized. */
  2939 	if (nd > strtod_diglim) {
  2940 		/* ASSERT(strtod_diglim >= 18); 18 == one more than the */
  2941 		/* minimum number of decimal digits to distinguish double values */
  2942 		/* in IEEE arithmetic. */
  2943 		i = j = 18;
  2944 		if (i > nd0)
  2945 			j += bc.dplen;
  2946 		for(;;) {
  2947 			if (--j < bc.dp1 && j >= bc.dp0)
  2948 				j = bc.dp0 - 1;
  2949 			if (s0[j] != '0')
  2950 				break;
  2951 			--i;
  2953 		e += nd - i;
  2954 		nd = i;
  2955 		if (nd0 > nd)
  2956 			nd0 = nd;
  2957 		if (nd < 9) { /* must recompute y */
  2958 			y = 0;
  2959 			for(i = 0; i < nd0; ++i)
  2960 				y = 10*y + s0[i] - '0';
  2961 			for(j = bc.dp1; i < nd; ++i)
  2962 				y = 10*y + s0[j++] - '0';
  2965 #endif
  2966 	bd0 = s2b(s0, nd0, nd, y, bc.dplen);
  2968 	for(;;) {
  2969 		bd = Balloc(bd0->k);
  2970 		Bcopy(bd, bd0);
  2971 		bb = d2b(&rv, &bbe, &bbbits);	/* rv = bb * 2^bbe */
  2972 		bs = i2b(1);
  2974 		if (e >= 0) {
  2975 			bb2 = bb5 = 0;
  2976 			bd2 = bd5 = e;
  2978 		else {
  2979 			bb2 = bb5 = -e;
  2980 			bd2 = bd5 = 0;
  2982 		if (bbe >= 0)
  2983 			bb2 += bbe;
  2984 		else
  2985 			bd2 -= bbe;
  2986 		bs2 = bb2;
  2987 #ifdef Honor_FLT_ROUNDS
  2988 		if (bc.rounding != 1)
  2989 			bs2++;
  2990 #endif
  2991 #ifdef Avoid_Underflow
  2992 		Lsb = LSB;
  2993 		Lsb1 = 0;
  2994 		j = bbe - bc.scale;
  2995 		i = j + bbbits - 1;	/* logb(rv) */
  2996 		j = P + 1 - bbbits;
  2997 		if (i < Emin) {	/* denormal */
  2998 			i = Emin - i;
  2999 			j -= i;
  3000 			if (i < 32)
  3001 				Lsb <<= i;
  3002 			else if (i < 52)
  3003 				Lsb1 = Lsb << (i-32);
  3004 			else
  3005 				Lsb1 = Exp_mask;
  3007 #else /*Avoid_Underflow*/
  3008 #ifdef Sudden_Underflow
  3009 #ifdef IBM
  3010 		j = 1 + 4*P - 3 - bbbits + ((bbe + bbbits - 1) & 3);
  3011 #else
  3012 		j = P + 1 - bbbits;
  3013 #endif
  3014 #else /*Sudden_Underflow*/
  3015 		j = bbe;
  3016 		i = j + bbbits - 1;	/* logb(rv) */
  3017 		if (i < Emin)	/* denormal */
  3018 			j += P - Emin;
  3019 		else
  3020 			j = P + 1 - bbbits;
  3021 #endif /*Sudden_Underflow*/
  3022 #endif /*Avoid_Underflow*/
  3023 		bb2 += j;
  3024 		bd2 += j;
  3025 #ifdef Avoid_Underflow
  3026 		bd2 += bc.scale;
  3027 #endif
  3028 		i = bb2 < bd2 ? bb2 : bd2;
  3029 		if (i > bs2)
  3030 			i = bs2;
  3031 		if (i > 0) {
  3032 			bb2 -= i;
  3033 			bd2 -= i;
  3034 			bs2 -= i;
  3036 		if (bb5 > 0) {
  3037 			bs = pow5mult(bs, bb5);
  3038 			bb1 = mult(bs, bb);
  3039 			Bfree(bb);
  3040 			bb = bb1;
  3042 		if (bb2 > 0)
  3043 			bb = lshift(bb, bb2);
  3044 		if (bd5 > 0)
  3045 			bd = pow5mult(bd, bd5);
  3046 		if (bd2 > 0)
  3047 			bd = lshift(bd, bd2);
  3048 		if (bs2 > 0)
  3049 			bs = lshift(bs, bs2);
  3050 		delta = diff(bb, bd);
  3051 		bc.dsign = delta->sign;
  3052 		delta->sign = 0;
  3053 		i = cmp(delta, bs);
  3054 #ifndef NO_STRTOD_BIGCOMP /*{*/
  3055 		if (bc.nd > nd && i <= 0) {
  3056 			if (bc.dsign) {
  3057 				/* Must use bigcomp(). */
  3058 				req_bigcomp = 1;
  3059 				break;
  3061 #ifdef Honor_FLT_ROUNDS
  3062 			if (bc.rounding != 1) {
  3063 				if (i < 0) {
  3064 					req_bigcomp = 1;
  3065 					break;
  3068 			else
  3069 #endif
  3070 				i = -1;	/* Discarded digits make delta smaller. */
  3072 #endif /*}*/
  3073 #ifdef Honor_FLT_ROUNDS /*{*/
  3074 		if (bc.rounding != 1) {
  3075 			if (i < 0) {
  3076 				/* Error is less than an ulp */
  3077 				if (!delta->x[0] && delta->wds <= 1) {
  3078 					/* exact */
  3079 #ifdef SET_INEXACT
  3080 					bc.inexact = 0;
  3081 #endif
  3082 					break;
  3084 				if (bc.rounding) {
  3085 					if (bc.dsign) {
  3086 						adj.d = 1.;
  3087 						goto apply_adj;
  3090 				else if (!bc.dsign) {
  3091 					adj.d = -1.;
  3092 					if (!word1(&rv)
  3093 					 && !(word0(&rv) & Frac_mask)) {
  3094 						y = word0(&rv) & Exp_mask;
  3095 #ifdef Avoid_Underflow
  3096 						if (!bc.scale || y > 2*P*Exp_msk1)
  3097 #else
  3098 						if (y)
  3099 #endif
  3101 						  delta = lshift(delta,Log2P);
  3102 						  if (cmp(delta, bs) <= 0)
  3103 							adj.d = -0.5;
  3106  apply_adj:
  3107 #ifdef Avoid_Underflow /*{*/
  3108 					if (bc.scale && (y = word0(&rv) & Exp_mask)
  3109 						<= 2*P*Exp_msk1)
  3110 					  word0(&adj) += (2*P+1)*Exp_msk1 - y;
  3111 #else
  3112 #ifdef Sudden_Underflow
  3113 					if ((word0(&rv) & Exp_mask) <=
  3114 							P*Exp_msk1) {
  3115 						word0(&rv) += P*Exp_msk1;
  3116 						dval(&rv) += adj.d*ulp(dval(&rv));
  3117 						word0(&rv) -= P*Exp_msk1;
  3119 					else
  3120 #endif /*Sudden_Underflow*/
  3121 #endif /*Avoid_Underflow}*/
  3122 					dval(&rv) += adj.d*ulp(&rv);
  3124 				break;
  3126 			adj.d = ratio(delta, bs);
  3127 			if (adj.d < 1.)
  3128 				adj.d = 1.;
  3129 			if (adj.d <= 0x7ffffffe) {
  3130 				/* adj = rounding ? ceil(adj) : floor(adj); */
  3131 				y = adj.d;
  3132 				if (y != adj.d) {
  3133 					if (!((bc.rounding>>1) ^ bc.dsign))
  3134 						y++;
  3135 					adj.d = y;
  3138 #ifdef Avoid_Underflow /*{*/
  3139 			if (bc.scale && (y = word0(&rv) & Exp_mask) <= 2*P*Exp_msk1)
  3140 				word0(&adj) += (2*P+1)*Exp_msk1 - y;
  3141 #else
  3142 #ifdef Sudden_Underflow
  3143 			if ((word0(&rv) & Exp_mask) <= P*Exp_msk1) {
  3144 				word0(&rv) += P*Exp_msk1;
  3145 				adj.d *= ulp(dval(&rv));
  3146 				if (bc.dsign)
  3147 					dval(&rv) += adj.d;
  3148 				else
  3149 					dval(&rv) -= adj.d;
  3150 				word0(&rv) -= P*Exp_msk1;
  3151 				goto cont;
  3153 #endif /*Sudden_Underflow*/
  3154 #endif /*Avoid_Underflow}*/
  3155 			adj.d *= ulp(&rv);
  3156 			if (bc.dsign) {
  3157 				if (word0(&rv) == Big0 && word1(&rv) == Big1)
  3158 					goto ovfl;
  3159 				dval(&rv) += adj.d;
  3161 			else
  3162 				dval(&rv) -= adj.d;
  3163 			goto cont;
  3165 #endif /*}Honor_FLT_ROUNDS*/
  3167 		if (i < 0) {
  3168 			/* Error is less than half an ulp -- check for
  3169 			 * special case of mantissa a power of two.
  3170 			 */
  3171 			if (bc.dsign || word1(&rv) || word0(&rv) & Bndry_mask
  3172 #ifdef IEEE_Arith /*{*/
  3173 #ifdef Avoid_Underflow
  3174 			 || (word0(&rv) & Exp_mask) <= (2*P+1)*Exp_msk1
  3175 #else
  3176 			 || (word0(&rv) & Exp_mask) <= Exp_msk1
  3177 #endif
  3178 #endif /*}*/
  3179 				) {
  3180 #ifdef SET_INEXACT
  3181 				if (!delta->x[0] && delta->wds <= 1)
  3182 					bc.inexact = 0;
  3183 #endif
  3184 				break;
  3186 			if (!delta->x[0] && delta->wds <= 1) {
  3187 				/* exact result */
  3188 #ifdef SET_INEXACT
  3189 				bc.inexact = 0;
  3190 #endif
  3191 				break;
  3193 			delta = lshift(delta,Log2P);
  3194 			if (cmp(delta, bs) > 0)
  3195 				goto drop_down;
  3196 			break;
  3198 		if (i == 0) {
  3199 			/* exactly half-way between */
  3200 			if (bc.dsign) {
  3201 				if ((word0(&rv) & Bndry_mask1) == Bndry_mask1
  3202 				 &&  word1(&rv) == (
  3203 #ifdef Avoid_Underflow
  3204 			(bc.scale && (y = word0(&rv) & Exp_mask) <= 2*P*Exp_msk1)
  3205 		? (0xffffffff & (0xffffffff << (2*P+1-(y>>Exp_shift)))) :
  3206 #endif
  3207 						   0xffffffff)) {
  3208 					/*boundary case -- increment exponent*/
  3209 					if (word0(&rv) == Big0 && word1(&rv) == Big1)
  3210 						goto ovfl;
  3211 					word0(&rv) = (word0(&rv) & Exp_mask)
  3212 						+ Exp_msk1
  3213 #ifdef IBM
  3214 						| Exp_msk1 >> 4
  3215 #endif
  3217 					word1(&rv) = 0;
  3218 #ifdef Avoid_Underflow
  3219 					bc.dsign = 0;
  3220 #endif
  3221 					break;
  3224 			else if (!(word0(&rv) & Bndry_mask) && !word1(&rv)) {
  3225  drop_down:
  3226 				/* boundary case -- decrement exponent */
  3227 #ifdef Sudden_Underflow /*{{*/
  3228 				L = word0(&rv) & Exp_mask;
  3229 #ifdef IBM
  3230 				if (L <  Exp_msk1)
  3231 #else
  3232 #ifdef Avoid_Underflow
  3233 				if (L <= (bc.scale ? (2*P+1)*Exp_msk1 : Exp_msk1))
  3234 #else
  3235 				if (L <= Exp_msk1)
  3236 #endif /*Avoid_Underflow*/
  3237 #endif /*IBM*/
  3239 					if (bc.nd >nd) {
  3240 						bc.uflchk = 1;
  3241 						break;
  3243 					goto undfl;
  3245 				L -= Exp_msk1;
  3246 #else /*Sudden_Underflow}{*/
  3247 #ifdef Avoid_Underflow
  3248 				if (bc.scale) {
  3249 					L = word0(&rv) & Exp_mask;
  3250 					if (L <= (2*P+1)*Exp_msk1) {
  3251 						if (L > (P+2)*Exp_msk1)
  3252 							/* round even ==> */
  3253 							/* accept rv */
  3254 							break;
  3255 						/* rv = smallest denormal */
  3256 						if (bc.nd >nd) {
  3257 							bc.uflchk = 1;
  3258 							break;
  3260 						goto undfl;
  3263 #endif /*Avoid_Underflow*/
  3264 				L = (word0(&rv) & Exp_mask) - Exp_msk1;
  3265 #endif /*Sudden_Underflow}}*/
  3266 				word0(&rv) = L | Bndry_mask1;
  3267 				word1(&rv) = 0xffffffff;
  3268 #ifdef IBM
  3269 				goto cont;
  3270 #else
  3271 #ifndef NO_STRTOD_BIGCOMP
  3272 				if (bc.nd > nd)
  3273 					goto cont;
  3274 #endif
  3275 				break;
  3276 #endif
  3278 #ifndef ROUND_BIASED
  3279 #ifdef Avoid_Underflow
  3280 			if (Lsb1) {
  3281 				if (!(word0(&rv) & Lsb1))
  3282 					break;
  3284 			else if (!(word1(&rv) & Lsb))
  3285 				break;
  3286 #else
  3287 			if (!(word1(&rv) & LSB))
  3288 				break;
  3289 #endif
  3290 #endif
  3291 			if (bc.dsign)
  3292 #ifdef Avoid_Underflow
  3293 				dval(&rv) += sulp(&rv, &bc);
  3294 #else
  3295 				dval(&rv) += ulp(&rv);
  3296 #endif
  3297 #ifndef ROUND_BIASED
  3298 			else {
  3299 #ifdef Avoid_Underflow
  3300 				dval(&rv) -= sulp(&rv, &bc);
  3301 #else
  3302 				dval(&rv) -= ulp(&rv);
  3303 #endif
  3304 #ifndef Sudden_Underflow
  3305 				if (!dval(&rv)) {
  3306 					if (bc.nd >nd) {
  3307 						bc.uflchk = 1;
  3308 						break;
  3310 					goto undfl;
  3312 #endif
  3314 #ifdef Avoid_Underflow
  3315 			bc.dsign = 1 - bc.dsign;
  3316 #endif
  3317 #endif
  3318 			break;
  3320 		if ((aadj = ratio(delta, bs)) <= 2.) {
  3321 			if (bc.dsign)
  3322 				aadj = aadj1 = 1.;
  3323 			else if (word1(&rv) || word0(&rv) & Bndry_mask) {
  3324 #ifndef Sudden_Underflow
  3325 				if (word1(&rv) == Tiny1 && !word0(&rv)) {
  3326 					if (bc.nd >nd) {
  3327 						bc.uflchk = 1;
  3328 						break;
  3330 					goto undfl;
  3332 #endif
  3333 				aadj = 1.;
  3334 				aadj1 = -1.;
  3336 			else {
  3337 				/* special case -- power of FLT_RADIX to be */
  3338 				/* rounded down... */
  3340 				if (aadj < 2./FLT_RADIX)
  3341 					aadj = 1./FLT_RADIX;
  3342 				else
  3343 					aadj *= 0.5;
  3344 				aadj1 = -aadj;
  3347 		else {
  3348 			aadj *= 0.5;
  3349 			aadj1 = bc.dsign ? aadj : -aadj;
  3350 #ifdef Check_FLT_ROUNDS
  3351 			switch(bc.rounding) {
  3352 				case 2: /* towards +infinity */
  3353 					aadj1 -= 0.5;
  3354 					break;
  3355 				case 0: /* towards 0 */
  3356 				case 3: /* towards -infinity */
  3357 					aadj1 += 0.5;
  3359 #else
  3360 			if (Flt_Rounds == 0)
  3361 				aadj1 += 0.5;
  3362 #endif /*Check_FLT_ROUNDS*/
  3364 		y = word0(&rv) & Exp_mask;
  3366 		/* Check for overflow */
  3368 		if (y == Exp_msk1*(DBL_MAX_EXP+Bias-1)) {
  3369 			dval(&rv0) = dval(&rv);
  3370 			word0(&rv) -= P*Exp_msk1;
  3371 			adj.d = aadj1 * ulp(&rv);
  3372 			dval(&rv) += adj.d;
  3373 			if ((word0(&rv) & Exp_mask) >=
  3374 					Exp_msk1*(DBL_MAX_EXP+Bias-P)) {
  3375 				if (word0(&rv0) == Big0 && word1(&rv0) == Big1)
  3376 					goto ovfl;
  3377 				word0(&rv) = Big0;
  3378 				word1(&rv) = Big1;
  3379 				goto cont;
  3381 			else
  3382 				word0(&rv) += P*Exp_msk1;
  3384 		else {
  3385 #ifdef Avoid_Underflow
  3386 			if (bc.scale && y <= 2*P*Exp_msk1) {
  3387 				if (aadj <= 0x7fffffff) {
  3388 					if ((z = aadj) <= 0)
  3389 						z = 1;
  3390 					aadj = z;
  3391 					aadj1 = bc.dsign ? aadj : -aadj;
  3393 				dval(&aadj2) = aadj1;
  3394 				word0(&aadj2) += (2*P+1)*Exp_msk1 - y;
  3395 				aadj1 = dval(&aadj2);
  3396 				adj.d = aadj1 * ulp(&rv);
  3397 				dval(&rv) += adj.d;
  3398 				if (rv.d == 0.)
  3399 #ifdef NO_STRTOD_BIGCOMP
  3400 					goto undfl;
  3401 #else
  3403 					if (bc.nd > nd)
  3404 						bc.dsign = 1;
  3405 					break;
  3407 #endif
  3409 			else {
  3410 				adj.d = aadj1 * ulp(&rv);
  3411 				dval(&rv) += adj.d;
  3413 #else
  3414 #ifdef Sudden_Underflow
  3415 			if ((word0(&rv) & Exp_mask) <= P*Exp_msk1) {
  3416 				dval(&rv0) = dval(&rv);
  3417 				word0(&rv) += P*Exp_msk1;
  3418 				adj.d = aadj1 * ulp(&rv);
  3419 				dval(&rv) += adj.d;
  3420 #ifdef IBM
  3421 				if ((word0(&rv) & Exp_mask) <  P*Exp_msk1)
  3422 #else
  3423 				if ((word0(&rv) & Exp_mask) <= P*Exp_msk1)
  3424 #endif
  3426 					if (word0(&rv0) == Tiny0
  3427 					 && word1(&rv0) == Tiny1) {
  3428 						if (bc.nd >nd) {
  3429 							bc.uflchk = 1;
  3430 							break;
  3432 						goto undfl;
  3434 					word0(&rv) = Tiny0;
  3435 					word1(&rv) = Tiny1;
  3436 					goto cont;
  3438 				else
  3439 					word0(&rv) -= P*Exp_msk1;
  3441 			else {
  3442 				adj.d = aadj1 * ulp(&rv);
  3443 				dval(&rv) += adj.d;
  3445 #else /*Sudden_Underflow*/
  3446 			/* Compute adj so that the IEEE rounding rules will
  3447 			 * correctly round rv + adj in some half-way cases.
  3448 			 * If rv * ulp(rv) is denormalized (i.e.,
  3449 			 * y <= (P-1)*Exp_msk1), we must adjust aadj to avoid
  3450 			 * trouble from bits lost to denormalization;
  3451 			 * example: 1.2e-307 .
  3452 			 */
  3453 			if (y <= (P-1)*Exp_msk1 && aadj > 1.) {
  3454 				aadj1 = (double)(int)(aadj + 0.5);
  3455 				if (!bc.dsign)
  3456 					aadj1 = -aadj1;
  3458 			adj.d = aadj1 * ulp(&rv);
  3459 			dval(&rv) += adj.d;
  3460 #endif /*Sudden_Underflow*/
  3461 #endif /*Avoid_Underflow*/
  3463 		z = word0(&rv) & Exp_mask;
  3464 #ifndef SET_INEXACT
  3465 		if (bc.nd == nd) {
  3466 #ifdef Avoid_Underflow
  3467 		if (!bc.scale)
  3468 #endif
  3469 		if (y == z) {
  3470 			/* Can we stop now? */
  3471 			L = (Long)aadj;
  3472 			aadj -= L;
  3473 			/* The tolerances below are conservative. */
  3474 			if (bc.dsign || word1(&rv) || word0(&rv) & Bndry_mask) {
  3475 				if (aadj < .4999999 || aadj > .5000001)
  3476 					break;
  3478 			else if (aadj < .4999999/FLT_RADIX)
  3479 				break;
  3482 #endif
  3483  cont:
  3484 		Bfree(bb);
  3485 		Bfree(bd);
  3486 		Bfree(bs);
  3487 		Bfree(delta);
  3489 	Bfree(bb);
  3490 	Bfree(bd);
  3491 	Bfree(bs);
  3492 	Bfree(bd0);
  3493 	Bfree(delta);
  3494 #ifndef NO_STRTOD_BIGCOMP
  3495 	if (req_bigcomp) {
  3496 		bd0 = 0;
  3497 		bc.e0 += nz1;
  3498 		bigcomp(&rv, s0, &bc);
  3499 		y = word0(&rv) & Exp_mask;
  3500 		if (y == Exp_mask)
  3501 			goto ovfl;
  3502 		if (y == 0 && rv.d == 0.)
  3503 			goto undfl;
  3505 #endif
  3506 #ifdef SET_INEXACT
  3507 	if (bc.inexact) {
  3508 		if (!oldinexact) {
  3509 			word0(&rv0) = Exp_1 + (70 << Exp_shift);
  3510 			word1(&rv0) = 0;
  3511 			dval(&rv0) += 1.;
  3514 	else if (!oldinexact)
  3515 		clear_inexact();
  3516 #endif
  3517 #ifdef Avoid_Underflow
  3518 	if (bc.scale) {
  3519 		word0(&rv0) = Exp_1 - 2*P*Exp_msk1;
  3520 		word1(&rv0) = 0;
  3521 		dval(&rv) *= dval(&rv0);
  3522 #ifndef NO_ERRNO
  3523 		/* try to avoid the bug of testing an 8087 register value */
  3524 #ifdef IEEE_Arith
  3525 		if (!(word0(&rv) & Exp_mask))
  3526 #else
  3527 		if (word0(&rv) == 0 && word1(&rv) == 0)
  3528 #endif
  3529 			errno = ERANGE;
  3530 #endif
  3532 #endif /* Avoid_Underflow */
  3533 #ifdef SET_INEXACT
  3534 	if (bc.inexact && !(word0(&rv) & Exp_mask)) {
  3535 		/* set underflow bit */
  3536 		dval(&rv0) = 1e-300;
  3537 		dval(&rv0) *= dval(&rv0);
  3539 #endif
  3540  ret:
  3541 	if (se)
  3542 		*se = (char *)s;
  3543 	return sign ? -dval(&rv) : dval(&rv);
  3546 #ifndef MULTIPLE_THREADS
  3547  static char *dtoa_result;
  3548 #endif
  3550  static char *
  3551 #ifdef KR_headers
  3552 rv_alloc(i) int i;
  3553 #else
  3554 rv_alloc(int i)
  3555 #endif
  3557 	int j, k, *r;
  3559 	j = sizeof(ULong);
  3560 	for(k = 0;
  3561 		sizeof(Bigint) - sizeof(ULong) - sizeof(int) + j <= i;
  3562 		j <<= 1)
  3563 			k++;
  3564 	r = (int*)Balloc(k);
  3565 	*r = k;
  3566 	return
  3567 #ifndef MULTIPLE_THREADS
  3568 	dtoa_result =
  3569 #endif
  3570 		(char *)(r+1);
  3573  static char *
  3574 #ifdef KR_headers
  3575 nrv_alloc(s, rve, n) char *s, **rve; int n;
  3576 #else
  3577 nrv_alloc(const char *s, char **rve, int n)
  3578 #endif
  3580 	char *rv, *t;
  3582 	t = rv = rv_alloc(n);
  3583 	while((*t = *s++)) t++;
  3584 	if (rve)
  3585 		*rve = t;
  3586 	return rv;
  3589 /* freedtoa(s) must be used to free values s returned by dtoa
  3590  * when MULTIPLE_THREADS is #defined.  It should be used in all cases,
  3591  * but for consistency with earlier versions of dtoa, it is optional
  3592  * when MULTIPLE_THREADS is not defined.
  3593  */
  3595  void
  3596 #ifdef KR_headers
  3597 freedtoa(s) char *s;
  3598 #else
  3599 freedtoa(char *s)
  3600 #endif
  3602 	Bigint *b = (Bigint *)((int *)s - 1);
  3603 	b->maxwds = 1 << (b->k = *(int*)b);
  3604 	Bfree(b);
  3605 #ifndef MULTIPLE_THREADS
  3606 	if (s == dtoa_result)
  3607 		dtoa_result = 0;
  3608 #endif
  3611 /* dtoa for IEEE arithmetic (dmg): convert double to ASCII string.
  3613  * Inspired by "How to Print Floating-Point Numbers Accurately" by
  3614  * Guy L. Steele, Jr. and Jon L. White [Proc. ACM SIGPLAN '90, pp. 112-126].
  3616  * Modifications:
  3617  *	1. Rather than iterating, we use a simple numeric overestimate
  3618  *	   to determine k = floor(log10(d)).  We scale relevant
  3619  *	   quantities using O(log2(k)) rather than O(k) multiplications.
  3620  *	2. For some modes > 2 (corresponding to ecvt and fcvt), we don't
  3621  *	   try to generate digits strictly left to right.  Instead, we
  3622  *	   compute with fewer bits and propagate the carry if necessary
  3623  *	   when rounding the final digit up.  This is often faster.
  3624  *	3. Under the assumption that input will be rounded nearest,
  3625  *	   mode 0 renders 1e23 as 1e23 rather than 9.999999999999999e22.
  3626  *	   That is, we allow equality in stopping tests when the
  3627  *	   round-nearest rule will give the same floating-point value
  3628  *	   as would satisfaction of the stopping test with strict
  3629  *	   inequality.
  3630  *	4. We remove common factors of powers of 2 from relevant
  3631  *	   quantities.
  3632  *	5. When converting floating-point integers less than 1e16,
  3633  *	   we use floating-point arithmetic rather than resorting
  3634  *	   to multiple-precision integers.
  3635  *	6. When asked to produce fewer than 15 digits, we first try
  3636  *	   to get by with floating-point arithmetic; we resort to
  3637  *	   multiple-precision integer arithmetic only if we cannot
  3638  *	   guarantee that the floating-point calculation has given
  3639  *	   the correctly rounded result.  For k requested digits and
  3640  *	   "uniformly" distributed input, the probability is
  3641  *	   something like 10^(k-15) that we must resort to the Long
  3642  *	   calculation.
  3643  */
  3645  char *
  3646 dtoa
  3647 #ifdef KR_headers
  3648 	(dd, mode, ndigits, decpt, sign, rve)
  3649 	double dd; int mode, ndigits, *decpt, *sign; char **rve;
  3650 #else
  3651 	(double dd, int mode, int ndigits, int *decpt, int *sign, char **rve)
  3652 #endif
  3654  /*	Arguments ndigits, decpt, sign are similar to those
  3655 	of ecvt and fcvt; trailing zeros are suppressed from
  3656 	the returned string.  If not null, *rve is set to point
  3657 	to the end of the return value.  If d is +-Infinity or NaN,
  3658 	then *decpt is set to 9999.
  3660 	mode:
  3661 		0 ==> shortest string that yields d when read in
  3662 			and rounded to nearest.
  3663 		1 ==> like 0, but with Steele & White stopping rule;
  3664 			e.g. with IEEE P754 arithmetic , mode 0 gives
  3665 			1e23 whereas mode 1 gives 9.999999999999999e22.
  3666 		2 ==> max(1,ndigits) significant digits.  This gives a
  3667 			return value similar to that of ecvt, except
  3668 			that trailing zeros are suppressed.
  3669 		3 ==> through ndigits past the decimal point.  This
  3670 			gives a return value similar to that from fcvt,
  3671 			except that trailing zeros are suppressed, and
  3672 			ndigits can be negative.
  3673 		4,5 ==> similar to 2 and 3, respectively, but (in
  3674 			round-nearest mode) with the tests of mode 0 to
  3675 			possibly return a shorter string that rounds to d.
  3676 			With IEEE arithmetic and compilation with
  3677 			-DHonor_FLT_ROUNDS, modes 4 and 5 behave the same
  3678 			as modes 2 and 3 when FLT_ROUNDS != 1.
  3679 		6-9 ==> Debugging modes similar to mode - 4:  don't try
  3680 			fast floating-point estimate (if applicable).
  3682 		Values of mode other than 0-9 are treated as mode 0.
  3684 		Sufficient space is allocated to the return value
  3685 		to hold the suppressed trailing zeros.
  3686 	*/
  3688 	int bbits, b2, b5, be, dig, i, ieps, ilim, ilim0, ilim1,
  3689 		j, j1, k, k0, k_check, leftright, m2, m5, s2, s5,
  3690 		spec_case, try_quick;
  3691 	Long L;
  3692 #ifndef Sudden_Underflow
  3693 	int denorm;
  3694 	ULong x;
  3695 #endif
  3696 	Bigint *b, *b1, *delta, *mlo, *mhi, *S;
  3697 	U d2, eps, u;
  3698 	double ds;
  3699 	char *s, *s0;
  3700 #ifndef No_leftright
  3701 #ifdef IEEE_Arith
  3702 	U eps1;
  3703 #endif
  3704 #endif
  3705 #ifdef SET_INEXACT
  3706 	int inexact, oldinexact;
  3707 #endif
  3708 #ifdef Honor_FLT_ROUNDS /*{*/
  3709 	int Rounding;
  3710 #ifdef Trust_FLT_ROUNDS /*{{ only define this if FLT_ROUNDS really works! */
  3711 	Rounding = Flt_Rounds;
  3712 #else /*}{*/
  3713 	Rounding = 1;
  3714 	switch(fegetround()) {
  3715 	  case FE_TOWARDZERO:	Rounding = 0; break;
  3716 	  case FE_UPWARD:	Rounding = 2; break;
  3717 	  case FE_DOWNWARD:	Rounding = 3;
  3719 #endif /*}}*/
  3720 #endif /*}*/
  3722 #ifndef MULTIPLE_THREADS
  3723 	if (dtoa_result) {
  3724 		freedtoa(dtoa_result);
  3725 		dtoa_result = 0;
  3727 #endif
  3729 	u.d = dd;
  3730 	if (word0(&u) & Sign_bit) {
  3731 		/* set sign for everything, including 0's and NaNs */
  3732 		*sign = 1;
  3733 		word0(&u) &= ~Sign_bit;	/* clear sign bit */
  3735 	else
  3736 		*sign = 0;
  3738 #if defined(IEEE_Arith) + defined(VAX)
  3739 #ifdef IEEE_Arith
  3740 	if ((word0(&u) & Exp_mask) == Exp_mask)
  3741 #else
  3742 	if (word0(&u)  == 0x8000)
  3743 #endif
  3745 		/* Infinity or NaN */
  3746 		*decpt = 9999;
  3747 #ifdef IEEE_Arith
  3748 		if (!word1(&u) && !(word0(&u) & 0xfffff))
  3749 			return nrv_alloc("Infinity", rve, 8);
  3750 #endif
  3751 		return nrv_alloc("NaN", rve, 3);
  3753 #endif
  3754 #ifdef IBM
  3755 	dval(&u) += 0; /* normalize */
  3756 #endif
  3757 	if (!dval(&u)) {
  3758 		*decpt = 1;
  3759 		return nrv_alloc("0", rve, 1);
  3762 #ifdef SET_INEXACT
  3763 	try_quick = oldinexact = get_inexact();
  3764 	inexact = 1;
  3765 #endif
  3766 #ifdef Honor_FLT_ROUNDS
  3767 	if (Rounding >= 2) {
  3768 		if (*sign)
  3769 			Rounding = Rounding == 2 ? 0 : 2;
  3770 		else
  3771 			if (Rounding != 2)
  3772 				Rounding = 0;
  3774 #endif
  3776 	b = d2b(&u, &be, &bbits);
  3777 #ifdef Sudden_Underflow
  3778 	i = (int)(word0(&u) >> Exp_shift1 & (Exp_mask>>Exp_shift1));
  3779 #else
  3780 	if ((i = (int)(word0(&u) >> Exp_shift1 & (Exp_mask>>Exp_shift1)))) {
  3781 #endif
  3782 		dval(&d2) = dval(&u);
  3783 		word0(&d2) &= Frac_mask1;
  3784 		word0(&d2) |= Exp_11;
  3785 #ifdef IBM
  3786 		if (j = 11 - hi0bits(word0(&d2) & Frac_mask))
  3787 			dval(&d2) /= 1 << j;
  3788 #endif
  3790 		/* log(x)	~=~ log(1.5) + (x-1.5)/1.5
  3791 		 * log10(x)	 =  log(x) / log(10)
  3792 		 *		~=~ log(1.5)/log(10) + (x-1.5)/(1.5*log(10))
  3793 		 * log10(d) = (i-Bias)*log(2)/log(10) + log10(d2)
  3795 		 * This suggests computing an approximation k to log10(d) by
  3797 		 * k = (i - Bias)*0.301029995663981
  3798 		 *	+ ( (d2-1.5)*0.289529654602168 + 0.176091259055681 );
  3800 		 * We want k to be too large rather than too small.
  3801 		 * The error in the first-order Taylor series approximation
  3802 		 * is in our favor, so we just round up the constant enough
  3803 		 * to compensate for any error in the multiplication of
  3804 		 * (i - Bias) by 0.301029995663981; since |i - Bias| <= 1077,
  3805 		 * and 1077 * 0.30103 * 2^-52 ~=~ 7.2e-14,
  3806 		 * adding 1e-13 to the constant term more than suffices.
  3807 		 * Hence we adjust the constant term to 0.1760912590558.
  3808 		 * (We could get a more accurate k by invoking log10,
  3809 		 *  but this is probably not worthwhile.)
  3810 		 */
  3812 		i -= Bias;
  3813 #ifdef IBM
  3814 		i <<= 2;
  3815 		i += j;
  3816 #endif
  3817 #ifndef Sudden_Underflow
  3818 		denorm = 0;
  3820 	else {
  3821 		/* d is denormalized */
  3823 		i = bbits + be + (Bias + (P-1) - 1);
  3824 		x = i > 32  ? word0(&u) << (64 - i) | word1(&u) >> (i - 32)
  3825 			    : word1(&u) << (32 - i);
  3826 		dval(&d2) = x;
  3827 		word0(&d2) -= 31*Exp_msk1; /* adjust exponent */
  3828 		i -= (Bias + (P-1) - 1) + 1;
  3829 		denorm = 1;
  3831 #endif
  3832 	ds = (dval(&d2)-1.5)*0.289529654602168 + 0.1760912590558 + i*0.301029995663981;
  3833 	k = (int)ds;
  3834 	if (ds < 0. && ds != k)
  3835 		k--;	/* want k = floor(ds) */
  3836 	k_check = 1;
  3837 	if (k >= 0 && k <= Ten_pmax) {
  3838 		if (dval(&u) < tens[k])
  3839 			k--;
  3840 		k_check = 0;
  3842 	j = bbits - i - 1;
  3843 	if (j >= 0) {
  3844 		b2 = 0;
  3845 		s2 = j;
  3847 	else {
  3848 		b2 = -j;
  3849 		s2 = 0;
  3851 	if (k >= 0) {
  3852 		b5 = 0;
  3853 		s5 = k;
  3854 		s2 += k;
  3856 	else {
  3857 		b2 -= k;
  3858 		b5 = -k;
  3859 		s5 = 0;
  3861 	if (mode < 0 || mode > 9)
  3862 		mode = 0;
  3864 #ifndef SET_INEXACT
  3865 #ifdef Check_FLT_ROUNDS
  3866 	try_quick = Rounding == 1;
  3867 #else
  3868 	try_quick = 1;
  3869 #endif
  3870 #endif /*SET_INEXACT*/
  3872 	if (mode > 5) {
  3873 		mode -= 4;
  3874 		try_quick = 0;
  3876 	leftright = 1;
  3877 	ilim = ilim1 = -1;	/* Values for cases 0 and 1; done here to */
  3878 				/* silence erroneous "gcc -Wall" warning. */
  3879 	switch(mode) {
  3880 		case 0:
  3881 		case 1:
  3882 			i = 18;
  3883 			ndigits = 0;
  3884 			break;
  3885 		case 2:
  3886 			leftright = 0;
  3887 			/* no break */
  3888 		case 4:
  3889 			if (ndigits <= 0)
  3890 				ndigits = 1;
  3891 			ilim = ilim1 = i = ndigits;
  3892 			break;
  3893 		case 3:
  3894 			leftright = 0;
  3895 			/* no break */
  3896 		case 5:
  3897 			i = ndigits + k + 1;
  3898 			ilim = i;
  3899 			ilim1 = i - 1;
  3900 			if (i <= 0)
  3901 				i = 1;
  3903 	s = s0 = rv_alloc(i);
  3905 #ifdef Honor_FLT_ROUNDS
  3906 	if (mode > 1 && Rounding != 1)
  3907 		leftright = 0;
  3908 #endif
  3910 	if (ilim >= 0 && ilim <= Quick_max && try_quick) {
  3912 		/* Try to get by with floating-point arithmetic. */
  3914 		i = 0;
  3915 		dval(&d2) = dval(&u);
  3916 		k0 = k;
  3917 		ilim0 = ilim;
  3918 		ieps = 2; /* conservative */
  3919 		if (k > 0) {
  3920 			ds = tens[k&0xf];
  3921 			j = k >> 4;
  3922 			if (j & Bletch) {
  3923 				/* prevent overflows */
  3924 				j &= Bletch - 1;
  3925 				dval(&u) /= bigtens[n_bigtens-1];
  3926 				ieps++;
  3928 			for(; j; j >>= 1, i++)
  3929 				if (j & 1) {
  3930 					ieps++;
  3931 					ds *= bigtens[i];
  3933 			dval(&u) /= ds;
  3935 		else if ((j1 = -k)) {
  3936 			dval(&u) *= tens[j1 & 0xf];
  3937 			for(j = j1 >> 4; j; j >>= 1, i++)
  3938 				if (j & 1) {
  3939 					ieps++;
  3940 					dval(&u) *= bigtens[i];
  3943 		if (k_check && dval(&u) < 1. && ilim > 0) {
  3944 			if (ilim1 <= 0)
  3945 				goto fast_failed;
  3946 			ilim = ilim1;
  3947 			k--;
  3948 			dval(&u) *= 10.;
  3949 			ieps++;
  3951 		dval(&eps) = ieps*dval(&u) + 7.;
  3952 		word0(&eps) -= (P-1)*Exp_msk1;
  3953 		if (ilim == 0) {
  3954 			S = mhi = 0;
  3955 			dval(&u) -= 5.;
  3956 			if (dval(&u) > dval(&eps))
  3957 				goto one_digit;
  3958 			if (dval(&u) < -dval(&eps))
  3959 				goto no_digits;
  3960 			goto fast_failed;
  3962 #ifndef No_leftright
  3963 		if (leftright) {
  3964 			/* Use Steele & White method of only
  3965 			 * generating digits needed.
  3966 			 */
  3967 			dval(&eps) = 0.5/tens[ilim-1] - dval(&eps);
  3968 #ifdef IEEE_Arith
  3969 			if (k0 < 0 && j1 >= 307) {
  3970 				eps1.d = 1.01e256; /* 1.01 allows roundoff in the next few lines */
  3971 				word0(&eps1) -= Exp_msk1 * (Bias+P-1);
  3972 				dval(&eps1) *= tens[j1 & 0xf];
  3973 				for(i = 0, j = (j1-256) >> 4; j; j >>= 1, i++)
  3974 					if (j & 1)
  3975 						dval(&eps1) *= bigtens[i];
  3976 				if (eps.d < eps1.d)
  3977 					eps.d = eps1.d;
  3979 #endif
  3980 			for(i = 0;;) {
  3981 				L = dval(&u);
  3982 				dval(&u) -= L;
  3983 				*s++ = '0' + (int)L;
  3984 				if (1. - dval(&u) < dval(&eps))
  3985 					goto bump_up;
  3986 				if (dval(&u) < dval(&eps))
  3987 					goto ret1;
  3988 				if (++i >= ilim)
  3989 					break;
  3990 				dval(&eps) *= 10.;
  3991 				dval(&u) *= 10.;
  3994 		else {
  3995 #endif
  3996 			/* Generate ilim digits, then fix them up. */
  3997 			dval(&eps) *= tens[ilim-1];
  3998 			for(i = 1;; i++, dval(&u) *= 10.) {
  3999 				L = (Long)(dval(&u));
  4000 				if (!(dval(&u) -= L))
  4001 					ilim = i;
  4002 				*s++ = '0' + (int)L;
  4003 				if (i == ilim) {
  4004 					if (dval(&u) > 0.5 + dval(&eps))
  4005 						goto bump_up;
  4006 					else if (dval(&u) < 0.5 - dval(&eps)) {
  4007 						while(*--s == '0');
  4008 						s++;
  4009 						goto ret1;
  4011 					break;
  4014 #ifndef No_leftright
  4016 #endif
  4017  fast_failed:
  4018 		s = s0;
  4019 		dval(&u) = dval(&d2);
  4020 		k = k0;
  4021 		ilim = ilim0;
  4024 	/* Do we have a "small" integer? */
  4026 	if (be >= 0 && k <= Int_max) {
  4027 		/* Yes. */
  4028 		ds = tens[k];
  4029 		if (ndigits < 0 && ilim <= 0) {
  4030 			S = mhi = 0;
  4031 			if (ilim < 0 || dval(&u) <= 5*ds)
  4032 				goto no_digits;
  4033 			goto one_digit;
  4035 		for(i = 1;; i++, dval(&u) *= 10.) {
  4036 			L = (Long)(dval(&u) / ds);
  4037 			dval(&u) -= L*ds;
  4038 #ifdef Check_FLT_ROUNDS
  4039 			/* If FLT_ROUNDS == 2, L will usually be high by 1 */
  4040 			if (dval(&u) < 0) {
  4041 				L--;
  4042 				dval(&u) += ds;
  4044 #endif
  4045 			*s++ = '0' + (int)L;
  4046 			if (!dval(&u)) {
  4047 #ifdef SET_INEXACT
  4048 				inexact = 0;
  4049 #endif
  4050 				break;
  4052 			if (i == ilim) {
  4053 #ifdef Honor_FLT_ROUNDS
  4054 				if (mode > 1)
  4055 				switch(Rounding) {
  4056 				  case 0: goto ret1;
  4057 				  case 2: goto bump_up;
  4059 #endif
  4060 				dval(&u) += dval(&u);
  4061 #ifdef ROUND_BIASED
  4062 				if (dval(&u) >= ds)
  4063 #else
  4064 				if (dval(&u) > ds || (dval(&u) == ds && L & 1))
  4065 #endif
  4067  bump_up:
  4068 					while(*--s == '9')
  4069 						if (s == s0) {
  4070 							k++;
  4071 							*s = '0';
  4072 							break;
  4074 					++*s++;
  4076 				break;
  4079 		goto ret1;
  4082 	m2 = b2;
  4083 	m5 = b5;
  4084 	mhi = mlo = 0;
  4085 	if (leftright) {
  4086 		i =
  4087 #ifndef Sudden_Underflow
  4088 			denorm ? be + (Bias + (P-1) - 1 + 1) :
  4089 #endif
  4090 #ifdef IBM
  4091 			1 + 4*P - 3 - bbits + ((bbits + be - 1) & 3);
  4092 #else
  4093 			1 + P - bbits;
  4094 #endif
  4095 		b2 += i;
  4096 		s2 += i;
  4097 		mhi = i2b(1);
  4099 	if (m2 > 0 && s2 > 0) {
  4100 		i = m2 < s2 ? m2 : s2;
  4101 		b2 -= i;
  4102 		m2 -= i;
  4103 		s2 -= i;
  4105 	if (b5 > 0) {
  4106 		if (leftright) {
  4107 			if (m5 > 0) {
  4108 				mhi = pow5mult(mhi, m5);
  4109 				b1 = mult(mhi, b);
  4110 				Bfree(b);
  4111 				b = b1;
  4113 			if ((j = b5 - m5))
  4114 				b = pow5mult(b, j);
  4116 		else
  4117 			b = pow5mult(b, b5);
  4119 	S = i2b(1);
  4120 	if (s5 > 0)
  4121 		S = pow5mult(S, s5);
  4123 	/* Check for special case that d is a normalized power of 2. */
  4125 	spec_case = 0;
  4126 	if ((mode < 2 || leftright)
  4127 #ifdef Honor_FLT_ROUNDS
  4128 			&& Rounding == 1
  4129 #endif
  4130 				) {
  4131 		if (!word1(&u) && !(word0(&u) & Bndry_mask)
  4132 #ifndef Sudden_Underflow
  4133 		 && word0(&u) & (Exp_mask & ~Exp_msk1)
  4134 #endif
  4135 				) {
  4136 			/* The special case */
  4137 			b2 += Log2P;
  4138 			s2 += Log2P;
  4139 			spec_case = 1;
  4143 	/* Arrange for convenient computation of quotients:
  4144 	 * shift left if necessary so divisor has 4 leading 0 bits.
  4146 	 * Perhaps we should just compute leading 28 bits of S once
  4147 	 * and for all and pass them and a shift to quorem, so it
  4148 	 * can do shifts and ors to compute the numerator for q.
  4149 	 */
  4150 	i = dshift(S, s2);
  4151 	b2 += i;
  4152 	m2 += i;
  4153 	s2 += i;
  4154 	if (b2 > 0)
  4155 		b = lshift(b, b2);
  4156 	if (s2 > 0)
  4157 		S = lshift(S, s2);
  4158 	if (k_check) {
  4159 		if (cmp(b,S) < 0) {
  4160 			k--;
  4161 			b = multadd(b, 10, 0);	/* we botched the k estimate */
  4162 			if (leftright)
  4163 				mhi = multadd(mhi, 10, 0);
  4164 			ilim = ilim1;
  4167 	if (ilim <= 0 && (mode == 3 || mode == 5)) {
  4168 		if (ilim < 0 || cmp(b,S = multadd(S,5,0)) <= 0) {
  4169 			/* no digits, fcvt style */
  4170  no_digits:
  4171 			k = -1 - ndigits;
  4172 			goto ret;
  4174  one_digit:
  4175 		*s++ = '1';
  4176 		k++;
  4177 		goto ret;
  4179 	if (leftright) {
  4180 		if (m2 > 0)
  4181 			mhi = lshift(mhi, m2);
  4183 		/* Compute mlo -- check for special case
  4184 		 * that d is a normalized power of 2.
  4185 		 */
  4187 		mlo = mhi;
  4188 		if (spec_case) {
  4189 			mhi = Balloc(mhi->k);
  4190 			Bcopy(mhi, mlo);
  4191 			mhi = lshift(mhi, Log2P);
  4194 		for(i = 1;;i++) {
  4195 			dig = quorem(b,S) + '0';
  4196 			/* Do we yet have the shortest decimal string
  4197 			 * that will round to d?
  4198 			 */
  4199 			j = cmp(b, mlo);
  4200 			delta = diff(S, mhi);
  4201 			j1 = delta->sign ? 1 : cmp(b, delta);
  4202 			Bfree(delta);
  4203 #ifndef ROUND_BIASED
  4204 			if (j1 == 0 && mode != 1 && !(word1(&u) & 1)
  4205 #ifdef Honor_FLT_ROUNDS
  4206 				&& Rounding >= 1
  4207 #endif
  4208 								   ) {
  4209 				if (dig == '9')
  4210 					goto round_9_up;
  4211 				if (j > 0)
  4212 					dig++;
  4213 #ifdef SET_INEXACT
  4214 				else if (!b->x[0] && b->wds <= 1)
  4215 					inexact = 0;
  4216 #endif
  4217 				*s++ = dig;
  4218 				goto ret;
  4220 #endif
  4221 			if (j < 0 || (j == 0 && mode != 1
  4222 #ifndef ROUND_BIASED
  4223 							&& !(word1(&u) & 1)
  4224 #endif
  4225 					)) {
  4226 				if (!b->x[0] && b->wds <= 1) {
  4227 #ifdef SET_INEXACT
  4228 					inexact = 0;
  4229 #endif
  4230 					goto accept_dig;
  4232 #ifdef Honor_FLT_ROUNDS
  4233 				if (mode > 1)
  4234 				 switch(Rounding) {
  4235 				  case 0: goto accept_dig;
  4236 				  case 2: goto keep_dig;
  4238 #endif /*Honor_FLT_ROUNDS*/
  4239 				if (j1 > 0) {
  4240 					b = lshift(b, 1);
  4241 					j1 = cmp(b, S);
  4242 #ifdef ROUND_BIASED
  4243 					if (j1 >= 0 /*)*/
  4244 #else
  4245 					if ((j1 > 0 || (j1 == 0 && dig & 1))
  4246 #endif
  4247 					&& dig++ == '9')
  4248 						goto round_9_up;
  4250  accept_dig:
  4251 				*s++ = dig;
  4252 				goto ret;
  4254 			if (j1 > 0) {
  4255 #ifdef Honor_FLT_ROUNDS
  4256 				if (!Rounding)
  4257 					goto accept_dig;
  4258 #endif
  4259 				if (dig == '9') { /* possible if i == 1 */
  4260  round_9_up:
  4261 					*s++ = '9';
  4262 					goto roundoff;
  4264 				*s++ = dig + 1;
  4265 				goto ret;
  4267 #ifdef Honor_FLT_ROUNDS
  4268  keep_dig:
  4269 #endif
  4270 			*s++ = dig;
  4271 			if (i == ilim)
  4272 				break;
  4273 			b = multadd(b, 10, 0);
  4274 			if (mlo == mhi)
  4275 				mlo = mhi = multadd(mhi, 10, 0);
  4276 			else {
  4277 				mlo = multadd(mlo, 10, 0);
  4278 				mhi = multadd(mhi, 10, 0);
  4282 	else
  4283 		for(i = 1;; i++) {
  4284 			*s++ = dig = quorem(b,S) + '0';
  4285 			if (!b->x[0] && b->wds <= 1) {
  4286 #ifdef SET_INEXACT
  4287 				inexact = 0;
  4288 #endif
  4289 				goto ret;
  4291 			if (i >= ilim)
  4292 				break;
  4293 			b = multadd(b, 10, 0);
  4296 	/* Round off last digit */
  4298 #ifdef Honor_FLT_ROUNDS
  4299 	switch(Rounding) {
  4300 	  case 0: goto trimzeros;
  4301 	  case 2: goto roundoff;
  4303 #endif
  4304 	b = lshift(b, 1);
  4305 	j = cmp(b, S);
  4306 #ifdef ROUND_BIASED
  4307 	if (j >= 0)
  4308 #else
  4309 	if (j > 0 || (j == 0 && dig & 1))
  4310 #endif
  4312  roundoff:
  4313 		while(*--s == '9')
  4314 			if (s == s0) {
  4315 				k++;
  4316 				*s++ = '1';
  4317 				goto ret;
  4319 		++*s++;
  4321 	else {
  4322 #ifdef Honor_FLT_ROUNDS
  4323  trimzeros:
  4324 #endif
  4325 		while(*--s == '0');
  4326 		s++;
  4328  ret:
  4329 	Bfree(S);
  4330 	if (mhi) {
  4331 		if (mlo && mlo != mhi)
  4332 			Bfree(mlo);
  4333 		Bfree(mhi);
  4335  ret1:
  4336 #ifdef SET_INEXACT
  4337 	if (inexact) {
  4338 		if (!oldinexact) {
  4339 			word0(&u) = Exp_1 + (70 << Exp_shift);
  4340 			word1(&u) = 0;
  4341 			dval(&u) += 1.;
  4344 	else if (!oldinexact)
  4345 		clear_inexact();
  4346 #endif
  4347 	Bfree(b);
  4348 	*s = 0;
  4349 	*decpt = k + 1;
  4350 	if (rve)
  4351 		*rve = s;
  4352 	return s0;
  4354 #ifdef __cplusplus
  4356 #endif

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