1 /****************************************************************
3 The author of this software is David M. Gay.
5 Copyright (C) 1998-2000 by Lucent Technologies
8 Permission to use, copy, modify, and distribute this software and
9 its documentation for any purpose and without fee is hereby
10 granted, provided that the above copyright notice appear in all
11 copies and that both that the copyright notice and this
12 permission notice and warranty disclaimer appear in supporting
13 documentation, and that the name of Lucent or any of its entities
14 not be used in advertising or publicity pertaining to
15 distribution of the software without specific, written prior
18 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
19 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
20 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
21 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
22 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
23 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
24 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
27 ****************************************************************/
29 /* This is a variation on dtoa.c that converts arbitary binary
30 floating-point formats to and from decimal notation. It uses
31 double-precision arithmetic internally, so there are still
32 various #ifdefs that adapt the calculations to the native
33 double-precision arithmetic (any of IEEE, VAX D_floating,
34 or IBM mainframe arithmetic).
36 Please send bug reports to David M. Gay (dmg at acm dot org,
37 with " at " changed at "@" and " dot " changed to ".").
40 /* On a machine with IEEE extended-precision registers, it is
41 * necessary to specify double-precision (53-bit) rounding precision
42 * before invoking strtod or dtoa. If the machine uses (the equivalent
43 * of) Intel 80x87 arithmetic, the call
44 * _control87(PC_53, MCW_PC);
45 * does this with many compilers. Whether this or another call is
46 * appropriate depends on the compiler; for this to work, it may be
47 * necessary to #include "float.h" or another system-dependent header
51 /* strtod for IEEE-, VAX-, and IBM-arithmetic machines.
53 * This strtod returns a nearest machine number to the input decimal
54 * string (or sets errno to ERANGE). With IEEE arithmetic, ties are
55 * broken by the IEEE round-even rule. Otherwise ties are broken by
56 * biased rounding (add half and chop).
58 * Inspired loosely by William D. Clinger's paper "How to Read Floating
59 * Point Numbers Accurately" [Proc. ACM SIGPLAN '90, pp. 112-126].
63 * 1. We only require IEEE, IBM, or VAX double-precision
64 * arithmetic (not IEEE double-extended).
65 * 2. We get by with floating-point arithmetic in a case that
66 * Clinger missed -- when we're computing d * 10^n
67 * for a small integer d and the integer n is not too
68 * much larger than 22 (the maximum integer k for which
69 * we can represent 10^k exactly), we may be able to
70 * compute (d*10^k) * 10^(e-k) with just one roundoff.
71 * 3. Rather than a bit-at-a-time adjustment of the binary
72 * result in the hard case, we use floating-point
73 * arithmetic to determine the adjustment to within
74 * one bit; only in really hard cases do we need to
75 * compute a second residual.
76 * 4. Because of 3., we don't need a large table of powers of 10
77 * for ten-to-e (just some small tables, e.g. of 10^k
82 * #define IEEE_8087 for IEEE-arithmetic machines where the least
83 * significant byte has the lowest address.
84 * #define IEEE_MC68k for IEEE-arithmetic machines where the most
85 * significant byte has the lowest address.
86 * #define Long int on machines with 32-bit ints and 64-bit longs.
87 * #define Sudden_Underflow for IEEE-format machines without gradual
88 * underflow (i.e., that flush to zero on underflow).
89 * #define IBM for IBM mainframe-style floating-point arithmetic.
90 * #define VAX for VAX-style floating-point arithmetic (D_floating).
91 * #define No_leftright to omit left-right logic in fast floating-point
92 * computation of dtoa and gdtoa. This will cause modes 4 and 5 to be
93 * treated the same as modes 2 and 3 for some inputs.
94 * #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3.
95 * #define RND_PRODQUOT to use rnd_prod and rnd_quot (assembly routines
96 * that use extended-precision instructions to compute rounded
97 * products and quotients) with IBM.
98 * #define ROUND_BIASED for IEEE-format with biased rounding and arithmetic
99 * that rounds toward +Infinity.
100 * #define ROUND_BIASED_without_Round_Up for IEEE-format with biased
101 * rounding when the underlying floating-point arithmetic uses
102 * unbiased rounding. This prevent using ordinary floating-point
103 * arithmetic when the result could be computed with one rounding error.
104 * #define Inaccurate_Divide for IEEE-format with correctly rounded
105 * products but inaccurate quotients, e.g., for Intel i860.
106 * #define NO_LONG_LONG on machines that do not have a "long long"
107 * integer type (of >= 64 bits). On such machines, you can
108 * #define Just_16 to store 16 bits per 32-bit Long when doing
109 * high-precision integer arithmetic. Whether this speeds things
110 * up or slows things down depends on the machine and the number
111 * being converted. If long long is available and the name is
112 * something other than "long long", #define Llong to be the name,
113 * and if "unsigned Llong" does not work as an unsigned version of
114 * Llong, #define #ULLong to be the corresponding unsigned type.
115 * #define KR_headers for old-style C function headers.
116 * #define Bad_float_h if your system lacks a float.h or if it does not
117 * define some or all of DBL_DIG, DBL_MAX_10_EXP, DBL_MAX_EXP,
118 * FLT_RADIX, FLT_ROUNDS, and DBL_MAX.
119 * #define MALLOC your_malloc, where your_malloc(n) acts like malloc(n)
120 * if memory is available and otherwise does something you deem
121 * appropriate. If MALLOC is undefined, malloc will be invoked
122 * directly -- and assumed always to succeed. Similarly, if you
123 * want something other than the system's free() to be called to
124 * recycle memory acquired from MALLOC, #define FREE to be the
125 * name of the alternate routine. (FREE or free is only called in
126 * pathological cases, e.g., in a gdtoa call after a gdtoa return in
127 * mode 3 with thousands of digits requested.)
128 * #define Omit_Private_Memory to omit logic (added Jan. 1998) for making
129 * memory allocations from a private pool of memory when possible.
130 * When used, the private pool is PRIVATE_MEM bytes long: 2304 bytes,
131 * unless #defined to be a different length. This default length
132 * suffices to get rid of MALLOC calls except for unusual cases,
133 * such as decimal-to-binary conversion of a very long string of
134 * digits. When converting IEEE double precision values, the
135 * longest string gdtoa can return is about 751 bytes long. For
136 * conversions by strtod of strings of 800 digits and all gdtoa
137 * conversions of IEEE doubles in single-threaded executions with
138 * 8-byte pointers, PRIVATE_MEM >= 7400 appears to suffice; with
139 * 4-byte pointers, PRIVATE_MEM >= 7112 appears adequate.
140 * #define NO_INFNAN_CHECK if you do not wish to have INFNAN_CHECK
141 * #defined automatically on IEEE systems. On such systems,
142 * when INFNAN_CHECK is #defined, strtod checks
143 * for Infinity and NaN (case insensitively).
144 * When INFNAN_CHECK is #defined and No_Hex_NaN is not #defined,
145 * strtodg also accepts (case insensitively) strings of the form
146 * NaN(x), where x is a string of hexadecimal digits (optionally
147 * preceded by 0x or 0X) and spaces; if there is only one string
148 * of hexadecimal digits, it is taken for the fraction bits of the
149 * resulting NaN; if there are two or more strings of hexadecimal
150 * digits, each string is assigned to the next available sequence
151 * of 32-bit words of fractions bits (starting with the most
152 * significant), right-aligned in each sequence.
153 * Unless GDTOA_NON_PEDANTIC_NANCHECK is #defined, input "NaN(...)"
154 * is consumed even when ... has the wrong form (in which case the
155 * "(...)" is consumed but ignored).
156 * #define MULTIPLE_THREADS if the system offers preemptively scheduled
157 * multiple threads. In this case, you must provide (or suitably
158 * #define) two locks, acquired by ACQUIRE_DTOA_LOCK(n) and freed
159 * by FREE_DTOA_LOCK(n) for n = 0 or 1. (The second lock, accessed
160 * in pow5mult, ensures lazy evaluation of only one copy of high
161 * powers of 5; omitting this lock would introduce a small
162 * probability of wasting memory, but would otherwise be harmless.)
163 * You must also invoke freedtoa(s) to free the value s returned by
164 * dtoa. You may do so whether or not MULTIPLE_THREADS is #defined.
165 * #define IMPRECISE_INEXACT if you do not care about the setting of
166 * the STRTOG_Inexact bits in the special case of doing IEEE double
167 * precision conversions (which could also be done by the strtod in
169 * #define NO_HEX_FP to disable recognition of C9x's hexadecimal
170 * floating-point constants.
171 * #define -DNO_ERRNO to suppress setting errno (in strtod.c and
173 * #define NO_STRING_H to use private versions of memcpy.
174 * On some K&R systems, it may also be necessary to
175 * #define DECLARE_SIZE_T in this case.
176 * #define USE_LOCALE to use the current locale's decimal_point value.
179 #ifndef GDTOAIMP_H_INCLUDED
180 #define GDTOAIMP_H_INCLUDED
183 #ifdef Honor_FLT_ROUNDS
189 #define Bug(x) {fprintf(stderr, "%s\n", x); exit(1);}
202 extern Char *MALLOC ANSI((size_t));
204 #define MALLOC malloc
208 #undef Avoid_Underflow
221 #define DBL_MAX_10_EXP 308
222 #define DBL_MAX_EXP 1024
224 #define DBL_MAX 1.7976931348623157e+308
229 #define DBL_MAX_10_EXP 75
230 #define DBL_MAX_EXP 63
232 #define DBL_MAX 7.2370055773322621e+75
237 #define DBL_MAX_10_EXP 38
238 #define DBL_MAX_EXP 127
240 #define DBL_MAX 1.7014118346046923e+38
245 #define LONG_MAX 2147483647
248 #else /* ifndef Bad_float_h */
250 #endif /* Bad_float_h */
253 #define Scale_Bit 0x10
273 #if defined(IEEE_8087) + defined(IEEE_MC68k) + defined(VAX) + defined(IBM) != 1
274 Exactly one of IEEE_8087, IEEE_MC68k, VAX, or IBM should be defined.
277 typedef union { double d; ULong L[2]; } U;
280 #define word0(x) (x)->L[1]
281 #define word1(x) (x)->L[0]
283 #define word0(x) (x)->L[0]
284 #define word1(x) (x)->L[1]
286 #define dval(x) (x)->d
288 /* The following definition of Storeinc is appropriate for MIPS processors.
289 * An alternative that might be better on some machines is
290 * #define Storeinc(a,b,c) (*a++ = b << 16 | c & 0xffff)
292 #if defined(IEEE_8087) + defined(VAX)
293 #define Storeinc(a,b,c) (((unsigned short *)a)[1] = (unsigned short)b, \
294 ((unsigned short *)a)[0] = (unsigned short)c, a++)
296 #define Storeinc(a,b,c) (((unsigned short *)a)[0] = (unsigned short)b, \
297 ((unsigned short *)a)[1] = (unsigned short)c, a++)
300 /* #define P DBL_MANT_DIG */
301 /* Ten_pmax = floor(P*log(2)/log(5)) */
302 /* Bletch = (highest power of 2 < DBL_MAX_10_EXP) / 16 */
303 /* Quick_max = floor((P-1)*log(FLT_RADIX)/log(10) - 1) */
304 /* Int_max = floor(P*log(FLT_RADIX)/log(10) - 1) */
308 #define Exp_shift1 20
309 #define Exp_msk1 0x100000
310 #define Exp_msk11 0x100000
311 #define Exp_mask 0x7ff00000
315 #define Exp_1 0x3ff00000
316 #define Exp_11 0x3ff00000
318 #define Frac_mask 0xfffff
319 #define Frac_mask1 0xfffff
322 #define Bndry_mask 0xfffff
323 #define Bndry_mask1 0xfffff
325 #define Sign_bit 0x80000000
334 #define Flt_Rounds FLT_ROUNDS
338 #endif /*Flt_Rounds*/
340 #else /* ifndef IEEE_Arith */
341 #undef Sudden_Underflow
342 #define Sudden_Underflow
347 #define Exp_shift1 24
348 #define Exp_msk1 0x1000000
349 #define Exp_msk11 0x1000000
350 #define Exp_mask 0x7f000000
353 #define Exp_1 0x41000000
354 #define Exp_11 0x41000000
355 #define Ebits 8 /* exponent has 7 bits, but 8 is the right value in b2d */
356 #define Frac_mask 0xffffff
357 #define Frac_mask1 0xffffff
360 #define Bndry_mask 0xefffff
361 #define Bndry_mask1 0xffffff
363 #define Sign_bit 0x80000000
365 #define Tiny0 0x100000
374 #define Exp_msk1 0x80
375 #define Exp_msk11 0x800000
376 #define Exp_mask 0x7f80
379 #define Exp_1 0x40800000
380 #define Exp_11 0x4080
382 #define Frac_mask 0x7fffff
383 #define Frac_mask1 0xffff007f
386 #define Bndry_mask 0xffff007f
387 #define Bndry_mask1 0xffff007f
389 #define Sign_bit 0x8000
395 #endif /* IBM, VAX */
396 #endif /* IEEE_Arith */
401 #ifdef ROUND_BIASED_without_Round_Up
408 #define rounded_product(a,b) a = rnd_prod(a, b)
409 #define rounded_quotient(a,b) a = rnd_quot(a, b)
411 extern double rnd_prod(), rnd_quot();
413 extern double rnd_prod(double, double), rnd_quot(double, double);
416 #define rounded_product(a,b) a *= b
417 #define rounded_quotient(a,b) a /= b
420 #define Big0 (Frac_mask1 | Exp_msk1*(DBL_MAX_EXP+Bias-1))
421 #define Big1 0xffffffff
433 /* When Pack_32 is not defined, we store 16 bits per 32-bit Long.
434 * This makes some inner loops simpler and sometimes saves work
435 * during multiplications, but it often seems to make things slightly
436 * slower. Hence the default is now to store 32 bits per Long.
439 #else /* long long available */
441 #define Llong long long
444 #define ULLong unsigned Llong
446 #endif /* NO_LONG_LONG */
452 #define ALL_ON 0xffffffff
457 #define ALL_ON 0xffff
460 #ifndef MULTIPLE_THREADS
461 #define ACQUIRE_DTOA_LOCK(n) /*nothing*/
462 #define FREE_DTOA_LOCK(n) /*nothing*/
470 int k, maxwds, sign, wds;
474 typedef struct Bigint Bigint;
477 #ifdef DECLARE_SIZE_T
478 typedef unsigned int size_t;
480 extern void memcpy_D2A ANSI((void*, const void*, size_t));
481 #define Bcopy(x,y) memcpy_D2A(&x->sign,&y->sign,y->wds*sizeof(ULong) + 2*sizeof(int))
482 #else /* !NO_STRING_H */
483 #define Bcopy(x,y) memcpy(&x->sign,&y->sign,y->wds*sizeof(ULong) + 2*sizeof(int))
484 #endif /* NO_STRING_H */
486 #define Balloc Balloc_D2A
487 #define Bfree Bfree_D2A
488 #define ULtoQ ULtoQ_D2A
489 #define ULtof ULtof_D2A
490 #define ULtod ULtod_D2A
491 #define ULtodd ULtodd_D2A
492 #define ULtox ULtox_D2A
493 #define ULtoxL ULtoxL_D2A
494 #define any_on any_on_D2A
496 #define bigtens bigtens_D2A
498 #define copybits copybits_D2A
500 #define decrement decrement_D2A
501 #define diff diff_D2A
502 #define dtoa_result dtoa_result_D2A
503 #define g__fmt g__fmt_D2A
504 #define gethex gethex_D2A
505 #define hexdig hexdig_D2A
506 #define hexnan hexnan_D2A
507 #define hi0bits(x) hi0bits_D2A((ULong)(x))
509 #define increment increment_D2A
510 #define lo0bits lo0bits_D2A
511 #define lshift lshift_D2A
512 #define match match_D2A
513 #define mult mult_D2A
514 #define multadd multadd_D2A
515 #define nrv_alloc nrv_alloc_D2A
516 #define pow5mult pow5mult_D2A
517 #define quorem quorem_D2A
518 #define ratio ratio_D2A
519 #define rshift rshift_D2A
520 #define rv_alloc rv_alloc_D2A
522 #define set_ones set_ones_D2A
523 #define strcp strcp_D2A
524 #define strtoIg strtoIg_D2A
526 #define tens tens_D2A
527 #define tinytens tinytens_D2A
528 #define tinytens tinytens_D2A
529 #define trailz trailz_D2A
532 extern char *dtoa_result;
533 extern CONST double bigtens[], tens[], tinytens[];
534 extern unsigned char hexdig[];
536 extern Bigint *Balloc ANSI((int));
537 extern void Bfree ANSI((Bigint*));
538 extern void ULtof ANSI((ULong*, ULong*, Long, int));
539 extern void ULtod ANSI((ULong*, ULong*, Long, int));
540 extern void ULtodd ANSI((ULong*, ULong*, Long, int));
541 extern void ULtoQ ANSI((ULong*, ULong*, Long, int));
542 extern void ULtox ANSI((UShort*, ULong*, Long, int));
543 extern void ULtoxL ANSI((ULong*, ULong*, Long, int));
544 extern ULong any_on ANSI((Bigint*, int));
545 extern double b2d ANSI((Bigint*, int*));
546 extern int cmp ANSI((Bigint*, Bigint*));
547 extern void copybits ANSI((ULong*, int, Bigint*));
548 extern Bigint *d2b ANSI((double, int*, int*));
549 extern void decrement ANSI((Bigint*));
550 extern Bigint *diff ANSI((Bigint*, Bigint*));
551 extern char *dtoa ANSI((double d, int mode, int ndigits,
552 int *decpt, int *sign, char **rve));
553 extern char *g__fmt ANSI((char*, char*, char*, int, ULong, size_t));
554 extern int gethex ANSI((CONST char**, FPI*, Long*, Bigint**, int));
555 extern void hexdig_init_D2A(Void);
556 extern int hexnan ANSI((CONST char**, FPI*, ULong*));
557 extern int hi0bits_D2A ANSI((ULong));
558 extern Bigint *i2b ANSI((int));
559 extern Bigint *increment ANSI((Bigint*));
560 extern int lo0bits ANSI((ULong*));
561 extern Bigint *lshift ANSI((Bigint*, int));
562 extern int match ANSI((CONST char**, char*));
563 extern Bigint *mult ANSI((Bigint*, Bigint*));
564 extern Bigint *multadd ANSI((Bigint*, int, int));
565 extern char *nrv_alloc ANSI((char*, char **, int));
566 extern Bigint *pow5mult ANSI((Bigint*, int));
567 extern int quorem ANSI((Bigint*, Bigint*));
568 extern double ratio ANSI((Bigint*, Bigint*));
569 extern void rshift ANSI((Bigint*, int));
570 extern char *rv_alloc ANSI((int));
571 extern Bigint *s2b ANSI((CONST char*, int, int, ULong, int));
572 extern Bigint *set_ones ANSI((Bigint*, int));
573 extern char *strcp ANSI((char*, const char*));
574 extern int strtoIg ANSI((CONST char*, char**, FPI*, Long*, Bigint**, int*));
575 extern double strtod ANSI((const char *s00, char **se));
576 extern Bigint *sum ANSI((Bigint*, Bigint*));
577 extern int trailz ANSI((Bigint*));
578 extern double ulp ANSI((U*));
584 * NAN_WORD0 and NAN_WORD1 are only referenced in strtod.c. Prior to
585 * 20050115, they used to be hard-wired here (to 0x7ff80000 and 0,
586 * respectively), but now are determined by compiling and running
587 * qnan.c to generate gd_qnan.h, which specifies d_QNAN0 and d_QNAN1.
588 * Formerly gdtoaimp.h recommended supplying suitable -DNAN_WORD0=...
589 * and -DNAN_WORD1=... values if necessary. This should still work.
590 * (On HP Series 700/800 machines, -DNAN_WORD0=0x7ff40000 works.)
593 #ifndef NO_INFNAN_CHECK
601 #define NAN_WORD0 d_QNAN0
604 #define NAN_WORD1 d_QNAN1
610 #define NAN_WORD0 d_QNAN1
613 #define NAN_WORD1 d_QNAN0
621 #ifdef Sudden_Underflow
627 #endif /* GDTOAIMP_H_INCLUDED */