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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 ***************************************************************/ | |
19 | |
20 /* Please send bug reports to David M. Gay (dmg at acm dot org, | |
21 * with " at " changed at "@" and " dot " changed to "."). */ | |
22 | |
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 */ | |
33 | |
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 */ | |
63 | |
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. | |
74 * #define Honor_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3 | |
75 * and strtod and dtoa should round accordingly. Unless Trust_FLT_ROUNDS | |
76 * is also #defined, fegetround() will be queried for the rounding mode. | |
77 * Note that both FLT_ROUNDS and fegetround() are specified by the C99 | |
78 * standard (and are specified to be consistent, with fesetround() | |
79 * affecting the value of FLT_ROUNDS), but that some (Linux) systems | |
80 * do not work correctly in this regard, so using fegetround() is more | |
81 * portable than using FLT_FOUNDS directly. | |
82 * #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3 | |
83 * and Honor_FLT_ROUNDS is not #defined. | |
84 * #define RND_PRODQUOT to use rnd_prod and rnd_quot (assembly routines | |
85 * that use extended-precision instructions to compute rounded | |
86 * products and quotients) with IBM. | |
87 * #define ROUND_BIASED for IEEE-format with biased rounding. | |
88 * #define Inaccurate_Divide for IEEE-format with correctly rounded | |
89 * products but inaccurate quotients, e.g., for Intel i860. | |
90 * #define NO_LONG_LONG on machines that do not have a "long long" | |
91 * integer type (of >= 64 bits). On such machines, you can | |
92 * #define Just_16 to store 16 bits per 32-bit Long when doing | |
93 * high-precision integer arithmetic. Whether this speeds things | |
94 * up or slows things down depends on the machine and the number | |
95 * being converted. If long long is available and the name is | |
96 * something other than "long long", #define Llong to be the name, | |
97 * and if "unsigned Llong" does not work as an unsigned version of | |
98 * Llong, #define #ULLong to be the corresponding unsigned type. | |
99 * #define KR_headers for old-style C function headers. | |
100 * #define Bad_float_h if your system lacks a float.h or if it does not | |
101 * define some or all of DBL_DIG, DBL_MAX_10_EXP, DBL_MAX_EXP, | |
102 * FLT_RADIX, FLT_ROUNDS, and DBL_MAX. | |
103 * #define MALLOC your_malloc, where your_malloc(n) acts like malloc(n) | |
104 * if memory is available and otherwise does something you deem | |
105 * appropriate. If MALLOC is undefined, malloc will be invoked | |
106 * directly -- and assumed always to succeed. | |
107 * #define Omit_Private_Memory to omit logic (added Jan. 1998) for making | |
108 * memory allocations from a private pool of memory when possible. | |
109 * When used, the private pool is PRIVATE_MEM bytes long: 2304 bytes, | |
110 * unless #defined to be a different length. This default length | |
111 * suffices to get rid of MALLOC calls except for unusual cases, | |
112 * such as decimal-to-binary conversion of a very long string of | |
113 * digits. The longest string dtoa can return is about 751 bytes | |
114 * long. For conversions by strtod of strings of 800 digits and | |
115 * all dtoa conversions in single-threaded executions with 8-byte | |
116 * pointers, PRIVATE_MEM >= 7400 appears to suffice; with 4-byte | |
117 * pointers, PRIVATE_MEM >= 7112 appears adequate. | |
118 * #define NO_INFNAN_CHECK if you do not wish to have INFNAN_CHECK | |
119 * #defined automatically on IEEE systems. On such systems, | |
120 * when INFNAN_CHECK is #defined, strtod checks | |
121 * for Infinity and NaN (case insensitively). On some systems | |
122 * (e.g., some HP systems), it may be necessary to #define NAN_WORD0 | |
123 * appropriately -- to the most significant word of a quiet NaN. | |
124 * (On HP Series 700/800 machines, -DNAN_WORD0=0x7ff40000 works.) | |
125 * When INFNAN_CHECK is #defined and No_Hex_NaN is not #defined, | |
126 * strtod also accepts (case insensitively) strings of the form | |
127 * NaN(x), where x is a string of hexadecimal digits and spaces; | |
128 * if there is only one string of hexadecimal digits, it is taken | |
129 * for the 52 fraction bits of the resulting NaN; if there are two | |
130 * or more strings of hex digits, the first is for the high 20 bits, | |
131 * the second and subsequent for the low 32 bits, with intervening | |
132 * white space ignored; but if this results in none of the 52 | |
133 * fraction bits being on (an IEEE Infinity symbol), then NAN_WORD0 | |
134 * and NAN_WORD1 are used instead. | |
135 * #define MULTIPLE_THREADS if the system offers preemptively scheduled | |
136 * multiple threads. In this case, you must provide (or suitably | |
137 * #define) two locks, acquired by ACQUIRE_DTOA_LOCK(n) and freed | |
138 * by FREE_DTOA_LOCK(n) for n = 0 or 1. (The second lock, accessed | |
139 * in pow5mult, ensures lazy evaluation of only one copy of high | |
140 * powers of 5; omitting this lock would introduce a small | |
141 * probability of wasting memory, but would otherwise be harmless.) | |
142 * You must also invoke freedtoa(s) to free the value s returned by | |
143 * dtoa. You may do so whether or not MULTIPLE_THREADS is #defined. | |
144 * #define NO_IEEE_Scale to disable new (Feb. 1997) logic in strtod that | |
145 * avoids underflows on inputs whose result does not underflow. | |
146 * If you #define NO_IEEE_Scale on a machine that uses IEEE-format | |
147 * floating-point numbers and flushes underflows to zero rather | |
148 * than implementing gradual underflow, then you must also #define | |
149 * Sudden_Underflow. | |
150 * #define YES_ALIAS to permit aliasing certain double values with | |
151 * arrays of ULongs. This leads to slightly better code with | |
152 * some compilers and was always used prior to 19990916, but it | |
153 * is not strictly legal and can cause trouble with aggressively | |
154 * optimizing compilers (e.g., gcc 2.95.1 under -O2). | |
155 * #define USE_LOCALE to use the current locale's decimal_point value. | |
156 * #define SET_INEXACT if IEEE arithmetic is being used and extra | |
157 * computation should be done to set the inexact flag when the | |
158 * result is inexact and avoid setting inexact when the result | |
159 * is exact. In this case, dtoa.c must be compiled in | |
160 * an environment, perhaps provided by #include "dtoa.c" in a | |
161 * suitable wrapper, that defines two functions, | |
162 * int get_inexact(void); | |
163 * void clear_inexact(void); | |
164 * such that get_inexact() returns a nonzero value if the | |
165 * inexact bit is already set, and clear_inexact() sets the | |
166 * inexact bit to 0. When SET_INEXACT is #defined, strtod | |
167 * also does extra computations to set the underflow and overflow | |
168 * flags when appropriate (i.e., when the result is tiny and | |
169 * inexact or when it is a numeric value rounded to +-infinity). | |
170 * #define NO_ERRNO if strtod should not assign errno = ERANGE when | |
171 * the result overflows to +-Infinity or underflows to 0. | |
172 */ | |
173 | |
174 #ifndef Long | |
175 #define Long long | |
176 #endif | |
177 #ifndef ULong | |
178 typedef unsigned Long ULong; | |
179 #endif | |
180 | |
181 #ifdef DEBUG | |
182 #include "stdio.h" | |
183 #define Bug(x) {fprintf(stderr, "%s\n", x); exit(1);} | |
184 #endif | |
185 | |
186 #include "stdlib.h" | |
187 #include "string.h" | |
188 | |
189 #ifdef USE_LOCALE | |
190 #include "locale.h" | |
191 #endif | |
192 | |
193 #ifdef MALLOC | |
194 #ifdef KR_headers | |
195 extern char *MALLOC(); | |
196 #else | |
197 extern void *MALLOC(size_t); | |
198 #endif | |
199 #else | |
200 #define MALLOC malloc | |
201 #endif | |
202 | |
203 #ifndef Omit_Private_Memory | |
204 #ifndef PRIVATE_MEM | |
205 #define PRIVATE_MEM 2304 | |
206 #endif | |
207 #define PRIVATE_mem ((PRIVATE_MEM+sizeof(double)-1)/sizeof(double)) | |
208 static double private_mem[PRIVATE_mem], *pmem_next = private_mem; | |
209 #endif | |
210 | |
211 #undef IEEE_Arith | |
212 #undef Avoid_Underflow | |
213 #ifdef IEEE_MC68k | |
214 #define IEEE_Arith | |
215 #endif | |
216 #ifdef IEEE_8087 | |
217 #define IEEE_Arith | |
218 #endif | |
219 | |
220 #ifdef IEEE_Arith | |
221 #ifndef NO_INFNAN_CHECK | |
222 #undef INFNAN_CHECK | |
223 #define INFNAN_CHECK | |
224 #endif | |
225 #else | |
226 #undef INFNAN_CHECK | |
227 #endif | |
228 | |
229 #include "errno.h" | |
230 | |
231 #ifdef Bad_float_h | |
232 | |
233 #ifdef IEEE_Arith | |
234 #define DBL_DIG 15 | |
235 #define DBL_MAX_10_EXP 308 | |
236 #define DBL_MAX_EXP 1024 | |
237 #define FLT_RADIX 2 | |
238 #endif /*IEEE_Arith*/ | |
239 | |
240 #ifdef IBM | |
241 #define DBL_DIG 16 | |
242 #define DBL_MAX_10_EXP 75 | |
243 #define DBL_MAX_EXP 63 | |
244 #define FLT_RADIX 16 | |
245 #define DBL_MAX 7.2370055773322621e+75 | |
246 #endif | |
247 | |
248 #ifdef VAX | |
249 #define DBL_DIG 16 | |
250 #define DBL_MAX_10_EXP 38 | |
251 #define DBL_MAX_EXP 127 | |
252 #define FLT_RADIX 2 | |
253 #define DBL_MAX 1.7014118346046923e+38 | |
254 #endif | |
255 | |
256 #ifndef LONG_MAX | |
257 #define LONG_MAX 2147483647 | |
258 #endif | |
259 | |
260 #else /* ifndef Bad_float_h */ | |
261 #include "float.h" | |
262 #endif /* Bad_float_h */ | |
263 | |
264 #ifndef __MATH_H__ | |
265 #include "math.h" | |
266 #endif | |
267 | |
268 namespace dmg_fp { | |
269 | |
270 #ifndef CONST | |
271 #ifdef KR_headers | |
272 #define CONST /* blank */ | |
273 #else | |
274 #define CONST const | |
275 #endif | |
276 #endif | |
277 | |
278 #if defined(IEEE_8087) + defined(IEEE_MC68k) + defined(VAX) + defined(IBM) != 1 | |
279 Exactly one of IEEE_8087, IEEE_MC68k, VAX, or IBM should be defined. | |
280 #endif | |
281 | |
282 typedef union { double d; ULong L[2]; } U; | |
283 | |
284 #ifdef YES_ALIAS | |
285 #define dval(x) x | |
286 #ifdef IEEE_8087 | |
287 #define word0(x) ((ULong *)&x)[1] | |
288 #define word1(x) ((ULong *)&x)[0] | |
289 #else | |
290 #define word0(x) ((ULong *)&x)[0] | |
291 #define word1(x) ((ULong *)&x)[1] | |
292 #endif | |
293 #else | |
294 #ifdef IEEE_8087 | |
295 #define word0(x) ((U*)&x)->L[1] | |
296 #define word1(x) ((U*)&x)->L[0] | |
297 #else | |
298 #define word0(x) ((U*)&x)->L[0] | |
299 #define word1(x) ((U*)&x)->L[1] | |
300 #endif | |
301 #define dval(x) ((U*)&x)->d | |
302 #endif | |
303 | |
304 /* The following definition of Storeinc is appropriate for MIPS processors. | |
305 * An alternative that might be better on some machines is | |
306 * #define Storeinc(a,b,c) (*a++ = b << 16 | c & 0xffff) | |
307 */ | |
308 #if defined(IEEE_8087) + defined(VAX) | |
309 #define Storeinc(a,b,c) (((unsigned short *)a)[1] = (unsigned short)b, \ | |
310 ((unsigned short *)a)[0] = (unsigned short)c, a++) | |
311 #else | |
312 #define Storeinc(a,b,c) (((unsigned short *)a)[0] = (unsigned short)b, \ | |
313 ((unsigned short *)a)[1] = (unsigned short)c, a++) | |
314 #endif | |
315 | |
316 /* #define P DBL_MANT_DIG */ | |
317 /* Ten_pmax = floor(P*log(2)/log(5)) */ | |
318 /* Bletch = (highest power of 2 < DBL_MAX_10_EXP) / 16 */ | |
319 /* Quick_max = floor((P-1)*log(FLT_RADIX)/log(10) - 1) */ | |
320 /* Int_max = floor(P*log(FLT_RADIX)/log(10) - 1) */ | |
321 | |
322 #ifdef IEEE_Arith | |
323 #define Exp_shift 20 | |
324 #define Exp_shift1 20 | |
325 #define Exp_msk1 0x100000 | |
326 #define Exp_msk11 0x100000 | |
327 #define Exp_mask 0x7ff00000 | |
328 #define P 53 | |
329 #define Bias 1023 | |
330 #define Emin (-1022) | |
331 #define Exp_1 0x3ff00000 | |
332 #define Exp_11 0x3ff00000 | |
333 #define Ebits 11 | |
334 #define Frac_mask 0xfffff | |
335 #define Frac_mask1 0xfffff | |
336 #define Ten_pmax 22 | |
337 #define Bletch 0x10 | |
338 #define Bndry_mask 0xfffff | |
339 #define Bndry_mask1 0xfffff | |
340 #define LSB 1 | |
341 #define Sign_bit 0x80000000 | |
342 #define Log2P 1 | |
343 #define Tiny0 0 | |
344 #define Tiny1 1 | |
345 #define Quick_max 14 | |
346 #define Int_max 14 | |
347 #ifndef NO_IEEE_Scale | |
348 #define Avoid_Underflow | |
349 #ifdef Flush_Denorm /* debugging option */ | |
350 #undef Sudden_Underflow | |
351 #endif | |
352 #endif | |
353 | |
354 #ifndef Flt_Rounds | |
355 #ifdef FLT_ROUNDS | |
356 #define Flt_Rounds FLT_ROUNDS | |
357 #else | |
358 #define Flt_Rounds 1 | |
359 #endif | |
360 #endif /*Flt_Rounds*/ | |
361 | |
362 #ifdef Honor_FLT_ROUNDS | |
363 #undef Check_FLT_ROUNDS | |
364 #define Check_FLT_ROUNDS | |
365 #else | |
366 #define Rounding Flt_Rounds | |
367 #endif | |
368 | |
369 #else /* ifndef IEEE_Arith */ | |
370 #undef Check_FLT_ROUNDS | |
371 #undef Honor_FLT_ROUNDS | |
372 #undef SET_INEXACT | |
373 #undef Sudden_Underflow | |
374 #define Sudden_Underflow | |
375 #ifdef IBM | |
376 #undef Flt_Rounds | |
377 #define Flt_Rounds 0 | |
378 #define Exp_shift 24 | |
379 #define Exp_shift1 24 | |
380 #define Exp_msk1 0x1000000 | |
381 #define Exp_msk11 0x1000000 | |
382 #define Exp_mask 0x7f000000 | |
383 #define P 14 | |
384 #define Bias 65 | |
385 #define Exp_1 0x41000000 | |
386 #define Exp_11 0x41000000 | |
387 #define Ebits 8 /* exponent has 7 bits, but 8 is the right value in b2d */ | |
388 #define Frac_mask 0xffffff | |
389 #define Frac_mask1 0xffffff | |
390 #define Bletch 4 | |
391 #define Ten_pmax 22 | |
392 #define Bndry_mask 0xefffff | |
393 #define Bndry_mask1 0xffffff | |
394 #define LSB 1 | |
395 #define Sign_bit 0x80000000 | |
396 #define Log2P 4 | |
397 #define Tiny0 0x100000 | |
398 #define Tiny1 0 | |
399 #define Quick_max 14 | |
400 #define Int_max 15 | |
401 #else /* VAX */ | |
402 #undef Flt_Rounds | |
403 #define Flt_Rounds 1 | |
404 #define Exp_shift 23 | |
405 #define Exp_shift1 7 | |
406 #define Exp_msk1 0x80 | |
407 #define Exp_msk11 0x800000 | |
408 #define Exp_mask 0x7f80 | |
409 #define P 56 | |
410 #define Bias 129 | |
411 #define Exp_1 0x40800000 | |
412 #define Exp_11 0x4080 | |
413 #define Ebits 8 | |
414 #define Frac_mask 0x7fffff | |
415 #define Frac_mask1 0xffff007f | |
416 #define Ten_pmax 24 | |
417 #define Bletch 2 | |
418 #define Bndry_mask 0xffff007f | |
419 #define Bndry_mask1 0xffff007f | |
420 #define LSB 0x10000 | |
421 #define Sign_bit 0x8000 | |
422 #define Log2P 1 | |
423 #define Tiny0 0x80 | |
424 #define Tiny1 0 | |
425 #define Quick_max 15 | |
426 #define Int_max 15 | |
427 #endif /* IBM, VAX */ | |
428 #endif /* IEEE_Arith */ | |
429 | |
430 #ifndef IEEE_Arith | |
431 #define ROUND_BIASED | |
432 #endif | |
433 | |
434 #ifdef RND_PRODQUOT | |
435 #define rounded_product(a,b) a = rnd_prod(a, b) | |
436 #define rounded_quotient(a,b) a = rnd_quot(a, b) | |
437 #ifdef KR_headers | |
438 extern double rnd_prod(), rnd_quot(); | |
439 #else | |
440 extern double rnd_prod(double, double), rnd_quot(double, double); | |
441 #endif | |
442 #else | |
443 #define rounded_product(a,b) a *= b | |
444 #define rounded_quotient(a,b) a /= b | |
445 #endif | |
446 | |
447 #define Big0 (Frac_mask1 | Exp_msk1*(DBL_MAX_EXP+Bias-1)) | |
448 #define Big1 0xffffffff | |
449 | |
450 #ifndef Pack_32 | |
451 #define Pack_32 | |
452 #endif | |
453 | |
454 #ifdef KR_headers | |
455 #define FFFFFFFF ((((unsigned long)0xffff)<<16)|(unsigned long)0xffff) | |
456 #else | |
457 #define FFFFFFFF 0xffffffffUL | |
458 #endif | |
459 | |
460 #ifdef NO_LONG_LONG | |
461 #undef ULLong | |
462 #ifdef Just_16 | |
463 #undef Pack_32 | |
464 /* When Pack_32 is not defined, we store 16 bits per 32-bit Long. | |
465 * This makes some inner loops simpler and sometimes saves work | |
466 * during multiplications, but it often seems to make things slightly | |
467 * slower. Hence the default is now to store 32 bits per Long. | |
468 */ | |
469 #endif | |
470 #else /* long long available */ | |
471 #ifndef Llong | |
472 #define Llong long long | |
473 #endif | |
474 #ifndef ULLong | |
475 #define ULLong unsigned Llong | |
476 #endif | |
477 #endif /* NO_LONG_LONG */ | |
478 | |
479 #ifndef MULTIPLE_THREADS | |
480 #define ACQUIRE_DTOA_LOCK(n) /*nothing*/ | |
481 #define FREE_DTOA_LOCK(n) /*nothing*/ | |
482 #endif | |
483 | |
484 #define Kmax 15 | |
485 | |
486 double strtod(const char *s00, char **se); | |
487 char *dtoa(double d, int mode, int ndigits, | |
488 int *decpt, int *sign, char **rve); | |
489 | |
490 struct | |
491 Bigint { | |
492 struct Bigint *next; | |
493 int k, maxwds, sign, wds; | |
494 ULong x[1]; | |
495 }; | |
496 | |
497 typedef struct Bigint Bigint; | |
498 | |
499 static Bigint *freelist[Kmax+1]; | |
500 | |
501 static Bigint * | |
502 Balloc | |
503 #ifdef KR_headers | |
504 (k) int k; | |
505 #else | |
506 (int k) | |
507 #endif | |
508 { | |
509 int x; | |
510 Bigint *rv; | |
511 #ifndef Omit_Private_Memory | |
512 unsigned int len; | |
513 #endif | |
514 | |
515 ACQUIRE_DTOA_LOCK(0); | |
516 if (rv = freelist[k]) { | |
517 freelist[k] = rv->next; | |
518 } | |
519 else { | |
520 x = 1 << k; | |
521 #ifdef Omit_Private_Memory | |
522 rv = (Bigint *)MALLOC(sizeof(Bigint) + (x-1)*sizeof(ULong)); | |
523 #else | |
524 len = (sizeof(Bigint) + (x-1)*sizeof(ULong) + sizeof(double) - 1
) | |
525 /sizeof(double); | |
526 if (pmem_next - private_mem + len <= PRIVATE_mem) { | |
527 rv = (Bigint*)pmem_next; | |
528 pmem_next += len; | |
529 } | |
530 else | |
531 rv = (Bigint*)MALLOC(len*sizeof(double)); | |
532 #endif | |
533 rv->k = k; | |
534 rv->maxwds = x; | |
535 } | |
536 FREE_DTOA_LOCK(0); | |
537 rv->sign = rv->wds = 0; | |
538 return rv; | |
539 } | |
540 | |
541 static void | |
542 Bfree | |
543 #ifdef KR_headers | |
544 (v) Bigint *v; | |
545 #else | |
546 (Bigint *v) | |
547 #endif | |
548 { | |
549 if (v) { | |
550 ACQUIRE_DTOA_LOCK(0); | |
551 v->next = freelist[v->k]; | |
552 freelist[v->k] = v; | |
553 FREE_DTOA_LOCK(0); | |
554 } | |
555 } | |
556 | |
557 #define Bcopy(x,y) memcpy((char *)&x->sign, (char *)&y->sign, \ | |
558 y->wds*sizeof(Long) + 2*sizeof(int)) | |
559 | |
560 static Bigint * | |
561 multadd | |
562 #ifdef KR_headers | |
563 (b, m, a) Bigint *b; int m, a; | |
564 #else | |
565 (Bigint *b, int m, int a) /* multiply by m and add a */ | |
566 #endif | |
567 { | |
568 int i, wds; | |
569 #ifdef ULLong | |
570 ULong *x; | |
571 ULLong carry, y; | |
572 #else | |
573 ULong carry, *x, y; | |
574 #ifdef Pack_32 | |
575 ULong xi, z; | |
576 #endif | |
577 #endif | |
578 Bigint *b1; | |
579 | |
580 wds = b->wds; | |
581 x = b->x; | |
582 i = 0; | |
583 carry = a; | |
584 do { | |
585 #ifdef ULLong | |
586 y = *x * (ULLong)m + carry; | |
587 carry = y >> 32; | |
588 *x++ = y & FFFFFFFF; | |
589 #else | |
590 #ifdef Pack_32 | |
591 xi = *x; | |
592 y = (xi & 0xffff) * m + carry; | |
593 z = (xi >> 16) * m + (y >> 16); | |
594 carry = z >> 16; | |
595 *x++ = (z << 16) + (y & 0xffff); | |
596 #else | |
597 y = *x * m + carry; | |
598 carry = y >> 16; | |
599 *x++ = y & 0xffff; | |
600 #endif | |
601 #endif | |
602 } | |
603 while(++i < wds); | |
604 if (carry) { | |
605 if (wds >= b->maxwds) { | |
606 b1 = Balloc(b->k+1); | |
607 Bcopy(b1, b); | |
608 Bfree(b); | |
609 b = b1; | |
610 } | |
611 b->x[wds++] = carry; | |
612 b->wds = wds; | |
613 } | |
614 return b; | |
615 } | |
616 | |
617 static Bigint * | |
618 s2b | |
619 #ifdef KR_headers | |
620 (s, nd0, nd, y9) CONST char *s; int nd0, nd; ULong y9; | |
621 #else | |
622 (CONST char *s, int nd0, int nd, ULong y9) | |
623 #endif | |
624 { | |
625 Bigint *b; | |
626 int i, k; | |
627 Long x, y; | |
628 | |
629 x = (nd + 8) / 9; | |
630 for(k = 0, y = 1; x > y; y <<= 1, k++) ; | |
631 #ifdef Pack_32 | |
632 b = Balloc(k); | |
633 b->x[0] = y9; | |
634 b->wds = 1; | |
635 #else | |
636 b = Balloc(k+1); | |
637 b->x[0] = y9 & 0xffff; | |
638 b->wds = (b->x[1] = y9 >> 16) ? 2 : 1; | |
639 #endif | |
640 | |
641 i = 9; | |
642 if (9 < nd0) { | |
643 s += 9; | |
644 do b = multadd(b, 10, *s++ - '0'); | |
645 while(++i < nd0); | |
646 s++; | |
647 } | |
648 else | |
649 s += 10; | |
650 for(; i < nd; i++) | |
651 b = multadd(b, 10, *s++ - '0'); | |
652 return b; | |
653 } | |
654 | |
655 static int | |
656 hi0bits | |
657 #ifdef KR_headers | |
658 (x) register ULong x; | |
659 #else | |
660 (register ULong x) | |
661 #endif | |
662 { | |
663 register int k = 0; | |
664 | |
665 if (!(x & 0xffff0000)) { | |
666 k = 16; | |
667 x <<= 16; | |
668 } | |
669 if (!(x & 0xff000000)) { | |
670 k += 8; | |
671 x <<= 8; | |
672 } | |
673 if (!(x & 0xf0000000)) { | |
674 k += 4; | |
675 x <<= 4; | |
676 } | |
677 if (!(x & 0xc0000000)) { | |
678 k += 2; | |
679 x <<= 2; | |
680 } | |
681 if (!(x & 0x80000000)) { | |
682 k++; | |
683 if (!(x & 0x40000000)) | |
684 return 32; | |
685 } | |
686 return k; | |
687 } | |
688 | |
689 static int | |
690 lo0bits | |
691 #ifdef KR_headers | |
692 (y) ULong *y; | |
693 #else | |
694 (ULong *y) | |
695 #endif | |
696 { | |
697 register int k; | |
698 register ULong x = *y; | |
699 | |
700 if (x & 7) { | |
701 if (x & 1) | |
702 return 0; | |
703 if (x & 2) { | |
704 *y = x >> 1; | |
705 return 1; | |
706 } | |
707 *y = x >> 2; | |
708 return 2; | |
709 } | |
710 k = 0; | |
711 if (!(x & 0xffff)) { | |
712 k = 16; | |
713 x >>= 16; | |
714 } | |
715 if (!(x & 0xff)) { | |
716 k += 8; | |
717 x >>= 8; | |
718 } | |
719 if (!(x & 0xf)) { | |
720 k += 4; | |
721 x >>= 4; | |
722 } | |
723 if (!(x & 0x3)) { | |
724 k += 2; | |
725 x >>= 2; | |
726 } | |
727 if (!(x & 1)) { | |
728 k++; | |
729 x >>= 1; | |
730 if (!x) | |
731 return 32; | |
732 } | |
733 *y = x; | |
734 return k; | |
735 } | |
736 | |
737 static Bigint * | |
738 i2b | |
739 #ifdef KR_headers | |
740 (i) int i; | |
741 #else | |
742 (int i) | |
743 #endif | |
744 { | |
745 Bigint *b; | |
746 | |
747 b = Balloc(1); | |
748 b->x[0] = i; | |
749 b->wds = 1; | |
750 return b; | |
751 } | |
752 | |
753 static Bigint * | |
754 mult | |
755 #ifdef KR_headers | |
756 (a, b) Bigint *a, *b; | |
757 #else | |
758 (Bigint *a, Bigint *b) | |
759 #endif | |
760 { | |
761 Bigint *c; | |
762 int k, wa, wb, wc; | |
763 ULong *x, *xa, *xae, *xb, *xbe, *xc, *xc0; | |
764 ULong y; | |
765 #ifdef ULLong | |
766 ULLong carry, z; | |
767 #else | |
768 ULong carry, z; | |
769 #ifdef Pack_32 | |
770 ULong z2; | |
771 #endif | |
772 #endif | |
773 | |
774 if (a->wds < b->wds) { | |
775 c = a; | |
776 a = b; | |
777 b = c; | |
778 } | |
779 k = a->k; | |
780 wa = a->wds; | |
781 wb = b->wds; | |
782 wc = wa + wb; | |
783 if (wc > a->maxwds) | |
784 k++; | |
785 c = Balloc(k); | |
786 for(x = c->x, xa = x + wc; x < xa; x++) | |
787 *x = 0; | |
788 xa = a->x; | |
789 xae = xa + wa; | |
790 xb = b->x; | |
791 xbe = xb + wb; | |
792 xc0 = c->x; | |
793 #ifdef ULLong | |
794 for(; xb < xbe; xc0++) { | |
795 if (y = *xb++) { | |
796 x = xa; | |
797 xc = xc0; | |
798 carry = 0; | |
799 do { | |
800 z = *x++ * (ULLong)y + *xc + carry; | |
801 carry = z >> 32; | |
802 *xc++ = z & FFFFFFFF; | |
803 } | |
804 while(x < xae); | |
805 *xc = carry; | |
806 } | |
807 } | |
808 #else | |
809 #ifdef Pack_32 | |
810 for(; xb < xbe; xb++, xc0++) { | |
811 if (y = *xb & 0xffff) { | |
812 x = xa; | |
813 xc = xc0; | |
814 carry = 0; | |
815 do { | |
816 z = (*x & 0xffff) * y + (*xc & 0xffff) + carry; | |
817 carry = z >> 16; | |
818 z2 = (*x++ >> 16) * y + (*xc >> 16) + carry; | |
819 carry = z2 >> 16; | |
820 Storeinc(xc, z2, z); | |
821 } | |
822 while(x < xae); | |
823 *xc = carry; | |
824 } | |
825 if (y = *xb >> 16) { | |
826 x = xa; | |
827 xc = xc0; | |
828 carry = 0; | |
829 z2 = *xc; | |
830 do { | |
831 z = (*x & 0xffff) * y + (*xc >> 16) + carry; | |
832 carry = z >> 16; | |
833 Storeinc(xc, z, z2); | |
834 z2 = (*x++ >> 16) * y + (*xc & 0xffff) + carry; | |
835 carry = z2 >> 16; | |
836 } | |
837 while(x < xae); | |
838 *xc = z2; | |
839 } | |
840 } | |
841 #else | |
842 for(; xb < xbe; xc0++) { | |
843 if (y = *xb++) { | |
844 x = xa; | |
845 xc = xc0; | |
846 carry = 0; | |
847 do { | |
848 z = *x++ * y + *xc + carry; | |
849 carry = z >> 16; | |
850 *xc++ = z & 0xffff; | |
851 } | |
852 while(x < xae); | |
853 *xc = carry; | |
854 } | |
855 } | |
856 #endif | |
857 #endif | |
858 for(xc0 = c->x, xc = xc0 + wc; wc > 0 && !*--xc; --wc) ; | |
859 c->wds = wc; | |
860 return c; | |
861 } | |
862 | |
863 static Bigint *p5s; | |
864 | |
865 static Bigint * | |
866 pow5mult | |
867 #ifdef KR_headers | |
868 (b, k) Bigint *b; int k; | |
869 #else | |
870 (Bigint *b, int k) | |
871 #endif | |
872 { | |
873 Bigint *b1, *p5, *p51; | |
874 int i; | |
875 static int p05[3] = { 5, 25, 125 }; | |
876 | |
877 if (i = k & 3) | |
878 b = multadd(b, p05[i-1], 0); | |
879 | |
880 if (!(k >>= 2)) | |
881 return b; | |
882 if (!(p5 = p5s)) { | |
883 /* first time */ | |
884 #ifdef MULTIPLE_THREADS | |
885 ACQUIRE_DTOA_LOCK(1); | |
886 if (!(p5 = p5s)) { | |
887 p5 = p5s = i2b(625); | |
888 p5->next = 0; | |
889 } | |
890 FREE_DTOA_LOCK(1); | |
891 #else | |
892 p5 = p5s = i2b(625); | |
893 p5->next = 0; | |
894 #endif | |
895 } | |
896 for(;;) { | |
897 if (k & 1) { | |
898 b1 = mult(b, p5); | |
899 Bfree(b); | |
900 b = b1; | |
901 } | |
902 if (!(k >>= 1)) | |
903 break; | |
904 if (!(p51 = p5->next)) { | |
905 #ifdef MULTIPLE_THREADS | |
906 ACQUIRE_DTOA_LOCK(1); | |
907 if (!(p51 = p5->next)) { | |
908 p51 = p5->next = mult(p5,p5); | |
909 p51->next = 0; | |
910 } | |
911 FREE_DTOA_LOCK(1); | |
912 #else | |
913 p51 = p5->next = mult(p5,p5); | |
914 p51->next = 0; | |
915 #endif | |
916 } | |
917 p5 = p51; | |
918 } | |
919 return b; | |
920 } | |
921 | |
922 static Bigint * | |
923 lshift | |
924 #ifdef KR_headers | |
925 (b, k) Bigint *b; int k; | |
926 #else | |
927 (Bigint *b, int k) | |
928 #endif | |
929 { | |
930 int i, k1, n, n1; | |
931 Bigint *b1; | |
932 ULong *x, *x1, *xe, z; | |
933 | |
934 #ifdef Pack_32 | |
935 n = k >> 5; | |
936 #else | |
937 n = k >> 4; | |
938 #endif | |
939 k1 = b->k; | |
940 n1 = n + b->wds + 1; | |
941 for(i = b->maxwds; n1 > i; i <<= 1) | |
942 k1++; | |
943 b1 = Balloc(k1); | |
944 x1 = b1->x; | |
945 for(i = 0; i < n; i++) | |
946 *x1++ = 0; | |
947 x = b->x; | |
948 xe = x + b->wds; | |
949 #ifdef Pack_32 | |
950 if (k &= 0x1f) { | |
951 k1 = 32 - k; | |
952 z = 0; | |
953 do { | |
954 *x1++ = *x << k | z; | |
955 z = *x++ >> k1; | |
956 } | |
957 while(x < xe); | |
958 if (*x1 = z) | |
959 ++n1; | |
960 } | |
961 #else | |
962 if (k &= 0xf) { | |
963 k1 = 16 - k; | |
964 z = 0; | |
965 do { | |
966 *x1++ = *x << k & 0xffff | z; | |
967 z = *x++ >> k1; | |
968 } | |
969 while(x < xe); | |
970 if (*x1 = z) | |
971 ++n1; | |
972 } | |
973 #endif | |
974 else do | |
975 *x1++ = *x++; | |
976 while(x < xe); | |
977 b1->wds = n1 - 1; | |
978 Bfree(b); | |
979 return b1; | |
980 } | |
981 | |
982 static int | |
983 cmp | |
984 #ifdef KR_headers | |
985 (a, b) Bigint *a, *b; | |
986 #else | |
987 (Bigint *a, Bigint *b) | |
988 #endif | |
989 { | |
990 ULong *xa, *xa0, *xb, *xb0; | |
991 int i, j; | |
992 | |
993 i = a->wds; | |
994 j = b->wds; | |
995 #ifdef DEBUG | |
996 if (i > 1 && !a->x[i-1]) | |
997 Bug("cmp called with a->x[a->wds-1] == 0"); | |
998 if (j > 1 && !b->x[j-1]) | |
999 Bug("cmp called with b->x[b->wds-1] == 0"); | |
1000 #endif | |
1001 if (i -= j) | |
1002 return i; | |
1003 xa0 = a->x; | |
1004 xa = xa0 + j; | |
1005 xb0 = b->x; | |
1006 xb = xb0 + j; | |
1007 for(;;) { | |
1008 if (*--xa != *--xb) | |
1009 return *xa < *xb ? -1 : 1; | |
1010 if (xa <= xa0) | |
1011 break; | |
1012 } | |
1013 return 0; | |
1014 } | |
1015 | |
1016 static Bigint * | |
1017 diff | |
1018 #ifdef KR_headers | |
1019 (a, b) Bigint *a, *b; | |
1020 #else | |
1021 (Bigint *a, Bigint *b) | |
1022 #endif | |
1023 { | |
1024 Bigint *c; | |
1025 int i, wa, wb; | |
1026 ULong *xa, *xae, *xb, *xbe, *xc; | |
1027 #ifdef ULLong | |
1028 ULLong borrow, y; | |
1029 #else | |
1030 ULong borrow, y; | |
1031 #ifdef Pack_32 | |
1032 ULong z; | |
1033 #endif | |
1034 #endif | |
1035 | |
1036 i = cmp(a,b); | |
1037 if (!i) { | |
1038 c = Balloc(0); | |
1039 c->wds = 1; | |
1040 c->x[0] = 0; | |
1041 return c; | |
1042 } | |
1043 if (i < 0) { | |
1044 c = a; | |
1045 a = b; | |
1046 b = c; | |
1047 i = 1; | |
1048 } | |
1049 else | |
1050 i = 0; | |
1051 c = Balloc(a->k); | |
1052 c->sign = i; | |
1053 wa = a->wds; | |
1054 xa = a->x; | |
1055 xae = xa + wa; | |
1056 wb = b->wds; | |
1057 xb = b->x; | |
1058 xbe = xb + wb; | |
1059 xc = c->x; | |
1060 borrow = 0; | |
1061 #ifdef ULLong | |
1062 do { | |
1063 y = (ULLong)*xa++ - *xb++ - borrow; | |
1064 borrow = y >> 32 & (ULong)1; | |
1065 *xc++ = y & FFFFFFFF; | |
1066 } | |
1067 while(xb < xbe); | |
1068 while(xa < xae) { | |
1069 y = *xa++ - borrow; | |
1070 borrow = y >> 32 & (ULong)1; | |
1071 *xc++ = y & FFFFFFFF; | |
1072 } | |
1073 #else | |
1074 #ifdef Pack_32 | |
1075 do { | |
1076 y = (*xa & 0xffff) - (*xb & 0xffff) - borrow; | |
1077 borrow = (y & 0x10000) >> 16; | |
1078 z = (*xa++ >> 16) - (*xb++ >> 16) - borrow; | |
1079 borrow = (z & 0x10000) >> 16; | |
1080 Storeinc(xc, z, y); | |
1081 } | |
1082 while(xb < xbe); | |
1083 while(xa < xae) { | |
1084 y = (*xa & 0xffff) - borrow; | |
1085 borrow = (y & 0x10000) >> 16; | |
1086 z = (*xa++ >> 16) - borrow; | |
1087 borrow = (z & 0x10000) >> 16; | |
1088 Storeinc(xc, z, y); | |
1089 } | |
1090 #else | |
1091 do { | |
1092 y = *xa++ - *xb++ - borrow; | |
1093 borrow = (y & 0x10000) >> 16; | |
1094 *xc++ = y & 0xffff; | |
1095 } | |
1096 while(xb < xbe); | |
1097 while(xa < xae) { | |
1098 y = *xa++ - borrow; | |
1099 borrow = (y & 0x10000) >> 16; | |
1100 *xc++ = y & 0xffff; | |
1101 } | |
1102 #endif | |
1103 #endif | |
1104 while(!*--xc) | |
1105 wa--; | |
1106 c->wds = wa; | |
1107 return c; | |
1108 } | |
1109 | |
1110 static double | |
1111 ulp | |
1112 #ifdef KR_headers | |
1113 (x) double x; | |
1114 #else | |
1115 (double x) | |
1116 #endif | |
1117 { | |
1118 register Long L; | |
1119 double a; | |
1120 | |
1121 L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1; | |
1122 #ifndef Avoid_Underflow | |
1123 #ifndef Sudden_Underflow | |
1124 if (L > 0) { | |
1125 #endif | |
1126 #endif | |
1127 #ifdef IBM | |
1128 L |= Exp_msk1 >> 4; | |
1129 #endif | |
1130 word0(a) = L; | |
1131 word1(a) = 0; | |
1132 #ifndef Avoid_Underflow | |
1133 #ifndef Sudden_Underflow | |
1134 } | |
1135 else { | |
1136 L = -L >> Exp_shift; | |
1137 if (L < Exp_shift) { | |
1138 word0(a) = 0x80000 >> L; | |
1139 word1(a) = 0; | |
1140 } | |
1141 else { | |
1142 word0(a) = 0; | |
1143 L -= Exp_shift; | |
1144 word1(a) = L >= 31 ? 1 : 1 << 31 - L; | |
1145 } | |
1146 } | |
1147 #endif | |
1148 #endif | |
1149 return dval(a); | |
1150 } | |
1151 | |
1152 static double | |
1153 b2d | |
1154 #ifdef KR_headers | |
1155 (a, e) Bigint *a; int *e; | |
1156 #else | |
1157 (Bigint *a, int *e) | |
1158 #endif | |
1159 { | |
1160 ULong *xa, *xa0, w, y, z; | |
1161 int k; | |
1162 double d; | |
1163 #ifdef VAX | |
1164 ULong d0, d1; | |
1165 #else | |
1166 #define d0 word0(d) | |
1167 #define d1 word1(d) | |
1168 #endif | |
1169 | |
1170 xa0 = a->x; | |
1171 xa = xa0 + a->wds; | |
1172 y = *--xa; | |
1173 #ifdef DEBUG | |
1174 if (!y) Bug("zero y in b2d"); | |
1175 #endif | |
1176 k = hi0bits(y); | |
1177 *e = 32 - k; | |
1178 #ifdef Pack_32 | |
1179 if (k < Ebits) { | |
1180 d0 = Exp_1 | y >> Ebits - k; | |
1181 w = xa > xa0 ? *--xa : 0; | |
1182 d1 = y << (32-Ebits) + k | w >> Ebits - k; | |
1183 goto ret_d; | |
1184 } | |
1185 z = xa > xa0 ? *--xa : 0; | |
1186 if (k -= Ebits) { | |
1187 d0 = Exp_1 | y << k | z >> 32 - k; | |
1188 y = xa > xa0 ? *--xa : 0; | |
1189 d1 = z << k | y >> 32 - k; | |
1190 } | |
1191 else { | |
1192 d0 = Exp_1 | y; | |
1193 d1 = z; | |
1194 } | |
1195 #else | |
1196 if (k < Ebits + 16) { | |
1197 z = xa > xa0 ? *--xa : 0; | |
1198 d0 = Exp_1 | y << k - Ebits | z >> Ebits + 16 - k; | |
1199 w = xa > xa0 ? *--xa : 0; | |
1200 y = xa > xa0 ? *--xa : 0; | |
1201 d1 = z << k + 16 - Ebits | w << k - Ebits | y >> 16 + Ebits - k; | |
1202 goto ret_d; | |
1203 } | |
1204 z = xa > xa0 ? *--xa : 0; | |
1205 w = xa > xa0 ? *--xa : 0; | |
1206 k -= Ebits + 16; | |
1207 d0 = Exp_1 | y << k + 16 | z << k | w >> 16 - k; | |
1208 y = xa > xa0 ? *--xa : 0; | |
1209 d1 = w << k + 16 | y << k; | |
1210 #endif | |
1211 ret_d: | |
1212 #ifdef VAX | |
1213 word0(d) = d0 >> 16 | d0 << 16; | |
1214 word1(d) = d1 >> 16 | d1 << 16; | |
1215 #else | |
1216 #undef d0 | |
1217 #undef d1 | |
1218 #endif | |
1219 return dval(d); | |
1220 } | |
1221 | |
1222 static Bigint * | |
1223 d2b | |
1224 #ifdef KR_headers | |
1225 (d, e, bits) double d; int *e, *bits; | |
1226 #else | |
1227 (double d, int *e, int *bits) | |
1228 #endif | |
1229 { | |
1230 Bigint *b; | |
1231 int de, k; | |
1232 ULong *x, y, z; | |
1233 #ifndef Sudden_Underflow | |
1234 int i; | |
1235 #endif | |
1236 #ifdef VAX | |
1237 ULong d0, d1; | |
1238 d0 = word0(d) >> 16 | word0(d) << 16; | |
1239 d1 = word1(d) >> 16 | word1(d) << 16; | |
1240 #else | |
1241 #define d0 word0(d) | |
1242 #define d1 word1(d) | |
1243 #endif | |
1244 | |
1245 #ifdef Pack_32 | |
1246 b = Balloc(1); | |
1247 #else | |
1248 b = Balloc(2); | |
1249 #endif | |
1250 x = b->x; | |
1251 | |
1252 z = d0 & Frac_mask; | |
1253 d0 &= 0x7fffffff; /* clear sign bit, which we ignore */ | |
1254 #ifdef Sudden_Underflow | |
1255 de = (int)(d0 >> Exp_shift); | |
1256 #ifndef IBM | |
1257 z |= Exp_msk11; | |
1258 #endif | |
1259 #else | |
1260 if (de = (int)(d0 >> Exp_shift)) | |
1261 z |= Exp_msk1; | |
1262 #endif | |
1263 #ifdef Pack_32 | |
1264 if (y = d1) { | |
1265 if (k = lo0bits(&y)) { | |
1266 x[0] = y | z << 32 - k; | |
1267 z >>= k; | |
1268 } | |
1269 else | |
1270 x[0] = y; | |
1271 #ifndef Sudden_Underflow | |
1272 i = | |
1273 #endif | |
1274 b->wds = (x[1] = z) ? 2 : 1; | |
1275 } | |
1276 else { | |
1277 #ifdef DEBUG | |
1278 if (!z) | |
1279 Bug("Zero passed to d2b"); | |
1280 #endif | |
1281 k = lo0bits(&z); | |
1282 x[0] = z; | |
1283 #ifndef Sudden_Underflow | |
1284 i = | |
1285 #endif | |
1286 b->wds = 1; | |
1287 k += 32; | |
1288 } | |
1289 #else | |
1290 if (y = d1) { | |
1291 if (k = lo0bits(&y)) | |
1292 if (k >= 16) { | |
1293 x[0] = y | z << 32 - k & 0xffff; | |
1294 x[1] = z >> k - 16 & 0xffff; | |
1295 x[2] = z >> k; | |
1296 i = 2; | |
1297 } | |
1298 else { | |
1299 x[0] = y & 0xffff; | |
1300 x[1] = y >> 16 | z << 16 - k & 0xffff; | |
1301 x[2] = z >> k & 0xffff; | |
1302 x[3] = z >> k+16; | |
1303 i = 3; | |
1304 } | |
1305 else { | |
1306 x[0] = y & 0xffff; | |
1307 x[1] = y >> 16; | |
1308 x[2] = z & 0xffff; | |
1309 x[3] = z >> 16; | |
1310 i = 3; | |
1311 } | |
1312 } | |
1313 else { | |
1314 #ifdef DEBUG | |
1315 if (!z) | |
1316 Bug("Zero passed to d2b"); | |
1317 #endif | |
1318 k = lo0bits(&z); | |
1319 if (k >= 16) { | |
1320 x[0] = z; | |
1321 i = 0; | |
1322 } | |
1323 else { | |
1324 x[0] = z & 0xffff; | |
1325 x[1] = z >> 16; | |
1326 i = 1; | |
1327 } | |
1328 k += 32; | |
1329 } | |
1330 while(!x[i]) | |
1331 --i; | |
1332 b->wds = i + 1; | |
1333 #endif | |
1334 #ifndef Sudden_Underflow | |
1335 if (de) { | |
1336 #endif | |
1337 #ifdef IBM | |
1338 *e = (de - Bias - (P-1) << 2) + k; | |
1339 *bits = 4*P + 8 - k - hi0bits(word0(d) & Frac_mask); | |
1340 #else | |
1341 *e = de - Bias - (P-1) + k; | |
1342 *bits = P - k; | |
1343 #endif | |
1344 #ifndef Sudden_Underflow | |
1345 } | |
1346 else { | |
1347 *e = de - Bias - (P-1) + 1 + k; | |
1348 #ifdef Pack_32 | |
1349 *bits = 32*i - hi0bits(x[i-1]); | |
1350 #else | |
1351 *bits = (i+2)*16 - hi0bits(x[i]); | |
1352 #endif | |
1353 } | |
1354 #endif | |
1355 return b; | |
1356 } | |
1357 #undef d0 | |
1358 #undef d1 | |
1359 | |
1360 static double | |
1361 ratio | |
1362 #ifdef KR_headers | |
1363 (a, b) Bigint *a, *b; | |
1364 #else | |
1365 (Bigint *a, Bigint *b) | |
1366 #endif | |
1367 { | |
1368 double da, db; | |
1369 int k, ka, kb; | |
1370 | |
1371 dval(da) = b2d(a, &ka); | |
1372 dval(db) = b2d(b, &kb); | |
1373 #ifdef Pack_32 | |
1374 k = ka - kb + 32*(a->wds - b->wds); | |
1375 #else | |
1376 k = ka - kb + 16*(a->wds - b->wds); | |
1377 #endif | |
1378 #ifdef IBM | |
1379 if (k > 0) { | |
1380 word0(da) += (k >> 2)*Exp_msk1; | |
1381 if (k &= 3) | |
1382 dval(da) *= 1 << k; | |
1383 } | |
1384 else { | |
1385 k = -k; | |
1386 word0(db) += (k >> 2)*Exp_msk1; | |
1387 if (k &= 3) | |
1388 dval(db) *= 1 << k; | |
1389 } | |
1390 #else | |
1391 if (k > 0) | |
1392 word0(da) += k*Exp_msk1; | |
1393 else { | |
1394 k = -k; | |
1395 word0(db) += k*Exp_msk1; | |
1396 } | |
1397 #endif | |
1398 return dval(da) / dval(db); | |
1399 } | |
1400 | |
1401 static CONST double | |
1402 tens[] = { | |
1403 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, | |
1404 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, | |
1405 1e20, 1e21, 1e22 | |
1406 #ifdef VAX | |
1407 , 1e23, 1e24 | |
1408 #endif | |
1409 }; | |
1410 | |
1411 static CONST double | |
1412 #ifdef IEEE_Arith | |
1413 bigtens[] = { 1e16, 1e32, 1e64, 1e128, 1e256 }; | |
1414 static CONST double tinytens[] = { 1e-16, 1e-32, 1e-64, 1e-128, | |
1415 #ifdef Avoid_Underflow | |
1416 9007199254740992.*9007199254740992.e-256 | |
1417 /* = 2^106 * 1e-256 */ | |
1418 #else | |
1419 1e-256 | |
1420 #endif | |
1421 }; | |
1422 /* The factor of 2^53 in tinytens[4] helps us avoid setting the underflow */ | |
1423 /* flag unnecessarily. It leads to a song and dance at the end of strtod. */ | |
1424 #define Scale_Bit 0x10 | |
1425 #define n_bigtens 5 | |
1426 #else | |
1427 #ifdef IBM | |
1428 bigtens[] = { 1e16, 1e32, 1e64 }; | |
1429 static CONST double tinytens[] = { 1e-16, 1e-32, 1e-64 }; | |
1430 #define n_bigtens 3 | |
1431 #else | |
1432 bigtens[] = { 1e16, 1e32 }; | |
1433 static CONST double tinytens[] = { 1e-16, 1e-32 }; | |
1434 #define n_bigtens 2 | |
1435 #endif | |
1436 #endif | |
1437 | |
1438 #ifdef INFNAN_CHECK | |
1439 | |
1440 #ifndef NAN_WORD0 | |
1441 #define NAN_WORD0 0x7ff80000 | |
1442 #endif | |
1443 | |
1444 #ifndef NAN_WORD1 | |
1445 #define NAN_WORD1 0 | |
1446 #endif | |
1447 | |
1448 static int | |
1449 match | |
1450 #ifdef KR_headers | |
1451 (sp, t) char **sp, *t; | |
1452 #else | |
1453 (CONST char **sp, char *t) | |
1454 #endif | |
1455 { | |
1456 int c, d; | |
1457 CONST char *s = *sp; | |
1458 | |
1459 while(d = *t++) { | |
1460 if ((c = *++s) >= 'A' && c <= 'Z') | |
1461 c += 'a' - 'A'; | |
1462 if (c != d) | |
1463 return 0; | |
1464 } | |
1465 *sp = s + 1; | |
1466 return 1; | |
1467 } | |
1468 | |
1469 #ifndef No_Hex_NaN | |
1470 static void | |
1471 hexnan | |
1472 #ifdef KR_headers | |
1473 (rvp, sp) double *rvp; CONST char **sp; | |
1474 #else | |
1475 (double *rvp, CONST char **sp) | |
1476 #endif | |
1477 { | |
1478 ULong c, x[2]; | |
1479 CONST char *s; | |
1480 int havedig, udx0, xshift; | |
1481 | |
1482 x[0] = x[1] = 0; | |
1483 havedig = xshift = 0; | |
1484 udx0 = 1; | |
1485 s = *sp; | |
1486 /* allow optional initial 0x or 0X */ | |
1487 while((c = *(CONST unsigned char*)(s+1)) && c <= ' ') | |
1488 ++s; | |
1489 if (s[1] == '0' && (s[2] == 'x' || s[2] == 'X')) | |
1490 s += 2; | |
1491 while(c = *(CONST unsigned char*)++s) { | |
1492 if (c >= '0' && c <= '9') | |
1493 c -= '0'; | |
1494 else if (c >= 'a' && c <= 'f') | |
1495 c += 10 - 'a'; | |
1496 else if (c >= 'A' && c <= 'F') | |
1497 c += 10 - 'A'; | |
1498 else if (c <= ' ') { | |
1499 if (udx0 && havedig) { | |
1500 udx0 = 0; | |
1501 xshift = 1; | |
1502 } | |
1503 continue; | |
1504 } | |
1505 #ifdef GDTOA_NON_PEDANTIC_NANCHECK | |
1506 else if (/*(*/ c == ')' && havedig) { | |
1507 *sp = s + 1; | |
1508 break; | |
1509 } | |
1510 else | |
1511 return; /* invalid form: don't change *sp */ | |
1512 #else | |
1513 else { | |
1514 do { | |
1515 if (/*(*/ c == ')') { | |
1516 *sp = s + 1; | |
1517 break; | |
1518 } | |
1519 } while(c = *++s); | |
1520 break; | |
1521 } | |
1522 #endif | |
1523 havedig = 1; | |
1524 if (xshift) { | |
1525 xshift = 0; | |
1526 x[0] = x[1]; | |
1527 x[1] = 0; | |
1528 } | |
1529 if (udx0) | |
1530 x[0] = (x[0] << 4) | (x[1] >> 28); | |
1531 x[1] = (x[1] << 4) | c; | |
1532 } | |
1533 if ((x[0] &= 0xfffff) || x[1]) { | |
1534 word0(*rvp) = Exp_mask | x[0]; | |
1535 word1(*rvp) = x[1]; | |
1536 } | |
1537 } | |
1538 #endif /*No_Hex_NaN*/ | |
1539 #endif /* INFNAN_CHECK */ | |
1540 | |
1541 double | |
1542 strtod | |
1543 #ifdef KR_headers | |
1544 (s00, se) CONST char *s00; char **se; | |
1545 #else | |
1546 (CONST char *s00, char **se) | |
1547 #endif | |
1548 { | |
1549 #ifdef Avoid_Underflow | |
1550 int scale; | |
1551 #endif | |
1552 int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, dsign, | |
1553 e, e1, esign, i, j, k, nd, nd0, nf, nz, nz0, sign; | |
1554 CONST char *s, *s0, *s1; | |
1555 double aadj, aadj1, adj, rv, rv0; | |
1556 Long L; | |
1557 ULong y, z; | |
1558 Bigint *bb, *bb1, *bd, *bd0, *bs, *delta; | |
1559 #ifdef SET_INEXACT | |
1560 int inexact, oldinexact; | |
1561 #endif | |
1562 #ifdef Honor_FLT_ROUNDS /*{*/ | |
1563 int Rounding; | |
1564 #ifdef Trust_FLT_ROUNDS /*{{ only define this if FLT_ROUNDS really works! */ | |
1565 Rounding = Flt_Rounds; | |
1566 #else /*}{*/ | |
1567 Rounding = 1; | |
1568 switch(fegetround()) { | |
1569 case FE_TOWARDZERO: Rounding = 0; break; | |
1570 case FE_UPWARD: Rounding = 2; break; | |
1571 case FE_DOWNWARD: Rounding = 3; | |
1572 } | |
1573 #endif /*}}*/ | |
1574 #endif /*}*/ | |
1575 #ifdef USE_LOCALE | |
1576 CONST char *s2; | |
1577 #endif | |
1578 | |
1579 sign = nz0 = nz = 0; | |
1580 dval(rv) = 0.; | |
1581 for(s = s00;;s++) switch(*s) { | |
1582 case '-': | |
1583 sign = 1; | |
1584 /* no break */ | |
1585 case '+': | |
1586 if (*++s) | |
1587 goto break2; | |
1588 /* no break */ | |
1589 case 0: | |
1590 goto ret0; | |
1591 case '\t': | |
1592 case '\n': | |
1593 case '\v': | |
1594 case '\f': | |
1595 case '\r': | |
1596 case ' ': | |
1597 continue; | |
1598 default: | |
1599 goto break2; | |
1600 } | |
1601 break2: | |
1602 if (*s == '0') { | |
1603 nz0 = 1; | |
1604 while(*++s == '0') ; | |
1605 if (!*s) | |
1606 goto ret; | |
1607 } | |
1608 s0 = s; | |
1609 y = z = 0; | |
1610 for(nd = nf = 0; (c = *s) >= '0' && c <= '9'; nd++, s++) | |
1611 if (nd < 9) | |
1612 y = 10*y + c - '0'; | |
1613 else if (nd < 16) | |
1614 z = 10*z + c - '0'; | |
1615 nd0 = nd; | |
1616 #ifdef USE_LOCALE | |
1617 s1 = localeconv()->decimal_point; | |
1618 if (c == *s1) { | |
1619 c = '.'; | |
1620 if (*++s1) { | |
1621 s2 = s; | |
1622 for(;;) { | |
1623 if (*++s2 != *s1) { | |
1624 c = 0; | |
1625 break; | |
1626 } | |
1627 if (!*++s1) { | |
1628 s = s2; | |
1629 break; | |
1630 } | |
1631 } | |
1632 } | |
1633 } | |
1634 #endif | |
1635 if (c == '.') { | |
1636 c = *++s; | |
1637 if (!nd) { | |
1638 for(; c == '0'; c = *++s) | |
1639 nz++; | |
1640 if (c > '0' && c <= '9') { | |
1641 s0 = s; | |
1642 nf += nz; | |
1643 nz = 0; | |
1644 goto have_dig; | |
1645 } | |
1646 goto dig_done; | |
1647 } | |
1648 for(; c >= '0' && c <= '9'; c = *++s) { | |
1649 have_dig: | |
1650 nz++; | |
1651 if (c -= '0') { | |
1652 nf += nz; | |
1653 for(i = 1; i < nz; i++) | |
1654 if (nd++ < 9) | |
1655 y *= 10; | |
1656 else if (nd <= DBL_DIG + 1) | |
1657 z *= 10; | |
1658 if (nd++ < 9) | |
1659 y = 10*y + c; | |
1660 else if (nd <= DBL_DIG + 1) | |
1661 z = 10*z + c; | |
1662 nz = 0; | |
1663 } | |
1664 } | |
1665 } | |
1666 dig_done: | |
1667 e = 0; | |
1668 if (c == 'e' || c == 'E') { | |
1669 if (!nd && !nz && !nz0) { | |
1670 goto ret0; | |
1671 } | |
1672 s00 = s; | |
1673 esign = 0; | |
1674 switch(c = *++s) { | |
1675 case '-': | |
1676 esign = 1; | |
1677 case '+': | |
1678 c = *++s; | |
1679 } | |
1680 if (c >= '0' && c <= '9') { | |
1681 while(c == '0') | |
1682 c = *++s; | |
1683 if (c > '0' && c <= '9') { | |
1684 L = c - '0'; | |
1685 s1 = s; | |
1686 while((c = *++s) >= '0' && c <= '9') | |
1687 L = 10*L + c - '0'; | |
1688 if (s - s1 > 8 || L > 19999) | |
1689 /* Avoid confusion from exponents | |
1690 * so large that e might overflow. | |
1691 */ | |
1692 e = 19999; /* safe for 16 bit ints */ | |
1693 else | |
1694 e = (int)L; | |
1695 if (esign) | |
1696 e = -e; | |
1697 } | |
1698 else | |
1699 e = 0; | |
1700 } | |
1701 else | |
1702 s = s00; | |
1703 } | |
1704 if (!nd) { | |
1705 if (!nz && !nz0) { | |
1706 #ifdef INFNAN_CHECK | |
1707 /* Check for Nan and Infinity */ | |
1708 switch(c) { | |
1709 case 'i': | |
1710 case 'I': | |
1711 if (match(&s,"nf")) { | |
1712 --s; | |
1713 if (!match(&s,"inity")) | |
1714 ++s; | |
1715 word0(rv) = 0x7ff00000; | |
1716 word1(rv) = 0; | |
1717 goto ret; | |
1718 } | |
1719 break; | |
1720 case 'n': | |
1721 case 'N': | |
1722 if (match(&s, "an")) { | |
1723 word0(rv) = NAN_WORD0; | |
1724 word1(rv) = NAN_WORD1; | |
1725 #ifndef No_Hex_NaN | |
1726 if (*s == '(') /*)*/ | |
1727 hexnan(&rv, &s); | |
1728 #endif | |
1729 goto ret; | |
1730 } | |
1731 } | |
1732 #endif /* INFNAN_CHECK */ | |
1733 ret0: | |
1734 s = s00; | |
1735 sign = 0; | |
1736 } | |
1737 goto ret; | |
1738 } | |
1739 e1 = e -= nf; | |
1740 | |
1741 /* Now we have nd0 digits, starting at s0, followed by a | |
1742 * decimal point, followed by nd-nd0 digits. The number we're | |
1743 * after is the integer represented by those digits times | |
1744 * 10**e */ | |
1745 | |
1746 if (!nd0) | |
1747 nd0 = nd; | |
1748 k = nd < DBL_DIG + 1 ? nd : DBL_DIG + 1; | |
1749 dval(rv) = y; | |
1750 if (k > 9) { | |
1751 #ifdef SET_INEXACT | |
1752 if (k > DBL_DIG) | |
1753 oldinexact = get_inexact(); | |
1754 #endif | |
1755 dval(rv) = tens[k - 9] * dval(rv) + z; | |
1756 } | |
1757 bd0 = 0; | |
1758 if (nd <= DBL_DIG | |
1759 #ifndef RND_PRODQUOT | |
1760 #ifndef Honor_FLT_ROUNDS | |
1761 && Flt_Rounds == 1 | |
1762 #endif | |
1763 #endif | |
1764 ) { | |
1765 if (!e) | |
1766 goto ret; | |
1767 if (e > 0) { | |
1768 if (e <= Ten_pmax) { | |
1769 #ifdef VAX | |
1770 goto vax_ovfl_check; | |
1771 #else | |
1772 #ifdef Honor_FLT_ROUNDS | |
1773 /* round correctly FLT_ROUNDS = 2 or 3 */ | |
1774 if (sign) { | |
1775 rv = -rv; | |
1776 sign = 0; | |
1777 } | |
1778 #endif | |
1779 /* rv = */ rounded_product(dval(rv), tens[e]); | |
1780 goto ret; | |
1781 #endif | |
1782 } | |
1783 i = DBL_DIG - nd; | |
1784 if (e <= Ten_pmax + i) { | |
1785 /* A fancier test would sometimes let us do | |
1786 * this for larger i values. | |
1787 */ | |
1788 #ifdef Honor_FLT_ROUNDS | |
1789 /* round correctly FLT_ROUNDS = 2 or 3 */ | |
1790 if (sign) { | |
1791 rv = -rv; | |
1792 sign = 0; | |
1793 } | |
1794 #endif | |
1795 e -= i; | |
1796 dval(rv) *= tens[i]; | |
1797 #ifdef VAX | |
1798 /* VAX exponent range is so narrow we must | |
1799 * worry about overflow here... | |
1800 */ | |
1801 vax_ovfl_check: | |
1802 word0(rv) -= P*Exp_msk1; | |
1803 /* rv = */ rounded_product(dval(rv), tens[e]); | |
1804 if ((word0(rv) & Exp_mask) | |
1805 > Exp_msk1*(DBL_MAX_EXP+Bias-1-P)) | |
1806 goto ovfl; | |
1807 word0(rv) += P*Exp_msk1; | |
1808 #else | |
1809 /* rv = */ rounded_product(dval(rv), tens[e]); | |
1810 #endif | |
1811 goto ret; | |
1812 } | |
1813 } | |
1814 #ifndef Inaccurate_Divide | |
1815 else if (e >= -Ten_pmax) { | |
1816 #ifdef Honor_FLT_ROUNDS | |
1817 /* round correctly FLT_ROUNDS = 2 or 3 */ | |
1818 if (sign) { | |
1819 rv = -rv; | |
1820 sign = 0; | |
1821 } | |
1822 #endif | |
1823 /* rv = */ rounded_quotient(dval(rv), tens[-e]); | |
1824 goto ret; | |
1825 } | |
1826 #endif | |
1827 } | |
1828 e1 += nd - k; | |
1829 | |
1830 #ifdef IEEE_Arith | |
1831 #ifdef SET_INEXACT | |
1832 inexact = 1; | |
1833 if (k <= DBL_DIG) | |
1834 oldinexact = get_inexact(); | |
1835 #endif | |
1836 #ifdef Avoid_Underflow | |
1837 scale = 0; | |
1838 #endif | |
1839 #ifdef Honor_FLT_ROUNDS | |
1840 if (Rounding >= 2) { | |
1841 if (sign) | |
1842 Rounding = Rounding == 2 ? 0 : 2; | |
1843 else | |
1844 if (Rounding != 2) | |
1845 Rounding = 0; | |
1846 } | |
1847 #endif | |
1848 #endif /*IEEE_Arith*/ | |
1849 | |
1850 /* Get starting approximation = rv * 10**e1 */ | |
1851 | |
1852 if (e1 > 0) { | |
1853 if (i = e1 & 15) | |
1854 dval(rv) *= tens[i]; | |
1855 if (e1 &= ~15) { | |
1856 if (e1 > DBL_MAX_10_EXP) { | |
1857 ovfl: | |
1858 #ifndef NO_ERRNO | |
1859 errno = ERANGE; | |
1860 #endif | |
1861 /* Can't trust HUGE_VAL */ | |
1862 #ifdef IEEE_Arith | |
1863 #ifdef Honor_FLT_ROUNDS | |
1864 switch(Rounding) { | |
1865 case 0: /* toward 0 */ | |
1866 case 3: /* toward -infinity */ | |
1867 word0(rv) = Big0; | |
1868 word1(rv) = Big1; | |
1869 break; | |
1870 default: | |
1871 word0(rv) = Exp_mask; | |
1872 word1(rv) = 0; | |
1873 } | |
1874 #else /*Honor_FLT_ROUNDS*/ | |
1875 word0(rv) = Exp_mask; | |
1876 word1(rv) = 0; | |
1877 #endif /*Honor_FLT_ROUNDS*/ | |
1878 #ifdef SET_INEXACT | |
1879 /* set overflow bit */ | |
1880 dval(rv0) = 1e300; | |
1881 dval(rv0) *= dval(rv0); | |
1882 #endif | |
1883 #else /*IEEE_Arith*/ | |
1884 word0(rv) = Big0; | |
1885 word1(rv) = Big1; | |
1886 #endif /*IEEE_Arith*/ | |
1887 if (bd0) | |
1888 goto retfree; | |
1889 goto ret; | |
1890 } | |
1891 e1 >>= 4; | |
1892 for(j = 0; e1 > 1; j++, e1 >>= 1) | |
1893 if (e1 & 1) | |
1894 dval(rv) *= bigtens[j]; | |
1895 /* The last multiplication could overflow. */ | |
1896 word0(rv) -= P*Exp_msk1; | |
1897 dval(rv) *= bigtens[j]; | |
1898 if ((z = word0(rv) & Exp_mask) | |
1899 > Exp_msk1*(DBL_MAX_EXP+Bias-P)) | |
1900 goto ovfl; | |
1901 if (z > Exp_msk1*(DBL_MAX_EXP+Bias-1-P)) { | |
1902 /* set to largest number */ | |
1903 /* (Can't trust DBL_MAX) */ | |
1904 word0(rv) = Big0; | |
1905 word1(rv) = Big1; | |
1906 } | |
1907 else | |
1908 word0(rv) += P*Exp_msk1; | |
1909 } | |
1910 } | |
1911 else if (e1 < 0) { | |
1912 e1 = -e1; | |
1913 if (i = e1 & 15) | |
1914 dval(rv) /= tens[i]; | |
1915 if (e1 >>= 4) { | |
1916 if (e1 >= 1 << n_bigtens) | |
1917 goto undfl; | |
1918 #ifdef Avoid_Underflow | |
1919 if (e1 & Scale_Bit) | |
1920 scale = 2*P; | |
1921 for(j = 0; e1 > 0; j++, e1 >>= 1) | |
1922 if (e1 & 1) | |
1923 dval(rv) *= tinytens[j]; | |
1924 if (scale && (j = 2*P + 1 - ((word0(rv) & Exp_mask) | |
1925 >> Exp_shift)) > 0) { | |
1926 /* scaled rv is denormal; clear j low bits */ | |
1927 if (j >= 32) { | |
1928 word1(rv) = 0; | |
1929 if (j >= 53) | |
1930 word0(rv) = (P+2)*Exp_msk1; | |
1931 else | |
1932 word0(rv) &= 0xffffffff << j-32; | |
1933 } | |
1934 else | |
1935 word1(rv) &= 0xffffffff << j; | |
1936 } | |
1937 #else | |
1938 for(j = 0; e1 > 1; j++, e1 >>= 1) | |
1939 if (e1 & 1) | |
1940 dval(rv) *= tinytens[j]; | |
1941 /* The last multiplication could underflow. */ | |
1942 dval(rv0) = dval(rv); | |
1943 dval(rv) *= tinytens[j]; | |
1944 if (!dval(rv)) { | |
1945 dval(rv) = 2.*dval(rv0); | |
1946 dval(rv) *= tinytens[j]; | |
1947 #endif | |
1948 if (!dval(rv)) { | |
1949 undfl: | |
1950 dval(rv) = 0.; | |
1951 #ifndef NO_ERRNO | |
1952 errno = ERANGE; | |
1953 #endif | |
1954 if (bd0) | |
1955 goto retfree; | |
1956 goto ret; | |
1957 } | |
1958 #ifndef Avoid_Underflow | |
1959 word0(rv) = Tiny0; | |
1960 word1(rv) = Tiny1; | |
1961 /* The refinement below will clean | |
1962 * this approximation up. | |
1963 */ | |
1964 } | |
1965 #endif | |
1966 } | |
1967 } | |
1968 | |
1969 /* Now the hard part -- adjusting rv to the correct value.*/ | |
1970 | |
1971 /* Put digits into bd: true value = bd * 10^e */ | |
1972 | |
1973 bd0 = s2b(s0, nd0, nd, y); | |
1974 | |
1975 for(;;) { | |
1976 bd = Balloc(bd0->k); | |
1977 Bcopy(bd, bd0); | |
1978 bb = d2b(dval(rv), &bbe, &bbbits); /* rv = bb * 2^bbe */ | |
1979 bs = i2b(1); | |
1980 | |
1981 if (e >= 0) { | |
1982 bb2 = bb5 = 0; | |
1983 bd2 = bd5 = e; | |
1984 } | |
1985 else { | |
1986 bb2 = bb5 = -e; | |
1987 bd2 = bd5 = 0; | |
1988 } | |
1989 if (bbe >= 0) | |
1990 bb2 += bbe; | |
1991 else | |
1992 bd2 -= bbe; | |
1993 bs2 = bb2; | |
1994 #ifdef Honor_FLT_ROUNDS | |
1995 if (Rounding != 1) | |
1996 bs2++; | |
1997 #endif | |
1998 #ifdef Avoid_Underflow | |
1999 j = bbe - scale; | |
2000 i = j + bbbits - 1; /* logb(rv) */ | |
2001 if (i < Emin) /* denormal */ | |
2002 j += P - Emin; | |
2003 else | |
2004 j = P + 1 - bbbits; | |
2005 #else /*Avoid_Underflow*/ | |
2006 #ifdef Sudden_Underflow | |
2007 #ifdef IBM | |
2008 j = 1 + 4*P - 3 - bbbits + ((bbe + bbbits - 1) & 3); | |
2009 #else | |
2010 j = P + 1 - bbbits; | |
2011 #endif | |
2012 #else /*Sudden_Underflow*/ | |
2013 j = bbe; | |
2014 i = j + bbbits - 1; /* logb(rv) */ | |
2015 if (i < Emin) /* denormal */ | |
2016 j += P - Emin; | |
2017 else | |
2018 j = P + 1 - bbbits; | |
2019 #endif /*Sudden_Underflow*/ | |
2020 #endif /*Avoid_Underflow*/ | |
2021 bb2 += j; | |
2022 bd2 += j; | |
2023 #ifdef Avoid_Underflow | |
2024 bd2 += scale; | |
2025 #endif | |
2026 i = bb2 < bd2 ? bb2 : bd2; | |
2027 if (i > bs2) | |
2028 i = bs2; | |
2029 if (i > 0) { | |
2030 bb2 -= i; | |
2031 bd2 -= i; | |
2032 bs2 -= i; | |
2033 } | |
2034 if (bb5 > 0) { | |
2035 bs = pow5mult(bs, bb5); | |
2036 bb1 = mult(bs, bb); | |
2037 Bfree(bb); | |
2038 bb = bb1; | |
2039 } | |
2040 if (bb2 > 0) | |
2041 bb = lshift(bb, bb2); | |
2042 if (bd5 > 0) | |
2043 bd = pow5mult(bd, bd5); | |
2044 if (bd2 > 0) | |
2045 bd = lshift(bd, bd2); | |
2046 if (bs2 > 0) | |
2047 bs = lshift(bs, bs2); | |
2048 delta = diff(bb, bd); | |
2049 dsign = delta->sign; | |
2050 delta->sign = 0; | |
2051 i = cmp(delta, bs); | |
2052 #ifdef Honor_FLT_ROUNDS | |
2053 if (Rounding != 1) { | |
2054 if (i < 0) { | |
2055 /* Error is less than an ulp */ | |
2056 if (!delta->x[0] && delta->wds <= 1) { | |
2057 /* exact */ | |
2058 #ifdef SET_INEXACT | |
2059 inexact = 0; | |
2060 #endif | |
2061 break; | |
2062 } | |
2063 if (Rounding) { | |
2064 if (dsign) { | |
2065 adj = 1.; | |
2066 goto apply_adj; | |
2067 } | |
2068 } | |
2069 else if (!dsign) { | |
2070 adj = -1.; | |
2071 if (!word1(rv) | |
2072 && !(word0(rv) & Frac_mask)) { | |
2073 y = word0(rv) & Exp_mask; | |
2074 #ifdef Avoid_Underflow | |
2075 if (!scale || y > 2*P*Exp_msk1) | |
2076 #else | |
2077 if (y) | |
2078 #endif | |
2079 { | |
2080 delta = lshift(delta,Log2P); | |
2081 if (cmp(delta, bs) <= 0) | |
2082 adj = -0.5; | |
2083 } | |
2084 } | |
2085 apply_adj: | |
2086 #ifdef Avoid_Underflow | |
2087 if (scale && (y = word0(rv) & Exp_mask) | |
2088 <= 2*P*Exp_msk1) | |
2089 word0(adj) += (2*P+1)*Exp_msk1 - y; | |
2090 #else | |
2091 #ifdef Sudden_Underflow | |
2092 if ((word0(rv) & Exp_mask) <= | |
2093 P*Exp_msk1) { | |
2094 word0(rv) += P*Exp_msk1; | |
2095 dval(rv) += adj*ulp(dval(rv)); | |
2096 word0(rv) -= P*Exp_msk1; | |
2097 } | |
2098 else | |
2099 #endif /*Sudden_Underflow*/ | |
2100 #endif /*Avoid_Underflow*/ | |
2101 dval(rv) += adj*ulp(dval(rv)); | |
2102 } | |
2103 break; | |
2104 } | |
2105 adj = ratio(delta, bs); | |
2106 if (adj < 1.) | |
2107 adj = 1.; | |
2108 if (adj <= 0x7ffffffe) { | |
2109 /* adj = rounding ? ceil(adj) : floor(adj); */ | |
2110 y = adj; | |
2111 if (y != adj) { | |
2112 if (!((Rounding>>1) ^ dsign)) | |
2113 y++; | |
2114 adj = y; | |
2115 } | |
2116 } | |
2117 #ifdef Avoid_Underflow | |
2118 if (scale && (y = word0(rv) & Exp_mask) <= 2*P*Exp_msk1) | |
2119 word0(adj) += (2*P+1)*Exp_msk1 - y; | |
2120 #else | |
2121 #ifdef Sudden_Underflow | |
2122 if ((word0(rv) & Exp_mask) <= P*Exp_msk1) { | |
2123 word0(rv) += P*Exp_msk1; | |
2124 adj *= ulp(dval(rv)); | |
2125 if (dsign) | |
2126 dval(rv) += adj; | |
2127 else | |
2128 dval(rv) -= adj; | |
2129 word0(rv) -= P*Exp_msk1; | |
2130 goto cont; | |
2131 } | |
2132 #endif /*Sudden_Underflow*/ | |
2133 #endif /*Avoid_Underflow*/ | |
2134 adj *= ulp(dval(rv)); | |
2135 if (dsign) { | |
2136 if (word0(rv) == Big0 && word1(rv) == Big1) | |
2137 goto ovfl; | |
2138 dval(rv) += adj; | |
2139 } | |
2140 else | |
2141 dval(rv) -= adj; | |
2142 goto cont; | |
2143 } | |
2144 #endif /*Honor_FLT_ROUNDS*/ | |
2145 | |
2146 if (i < 0) { | |
2147 /* Error is less than half an ulp -- check for | |
2148 * special case of mantissa a power of two. | |
2149 */ | |
2150 if (dsign || word1(rv) || word0(rv) & Bndry_mask | |
2151 #ifdef IEEE_Arith | |
2152 #ifdef Avoid_Underflow | |
2153 || (word0(rv) & Exp_mask) <= (2*P+1)*Exp_msk1 | |
2154 #else | |
2155 || (word0(rv) & Exp_mask) <= Exp_msk1 | |
2156 #endif | |
2157 #endif | |
2158 ) { | |
2159 #ifdef SET_INEXACT | |
2160 if (!delta->x[0] && delta->wds <= 1) | |
2161 inexact = 0; | |
2162 #endif | |
2163 break; | |
2164 } | |
2165 if (!delta->x[0] && delta->wds <= 1) { | |
2166 /* exact result */ | |
2167 #ifdef SET_INEXACT | |
2168 inexact = 0; | |
2169 #endif | |
2170 break; | |
2171 } | |
2172 delta = lshift(delta,Log2P); | |
2173 if (cmp(delta, bs) > 0) | |
2174 goto drop_down; | |
2175 break; | |
2176 } | |
2177 if (i == 0) { | |
2178 /* exactly half-way between */ | |
2179 if (dsign) { | |
2180 if ((word0(rv) & Bndry_mask1) == Bndry_mask1 | |
2181 && word1(rv) == ( | |
2182 #ifdef Avoid_Underflow | |
2183 (scale && (y = word0(rv) & Exp_mask) <= 2*P*Exp_msk1) | |
2184 ? (0xffffffff & (0xffffffff << (2*P+1-(y>>Exp_shift)))) : | |
2185 #endif | |
2186 0xffffffff)) { | |
2187 /*boundary case -- increment exponent*/ | |
2188 word0(rv) = (word0(rv) & Exp_mask) | |
2189 + Exp_msk1 | |
2190 #ifdef IBM | |
2191 | Exp_msk1 >> 4 | |
2192 #endif | |
2193 ; | |
2194 word1(rv) = 0; | |
2195 #ifdef Avoid_Underflow | |
2196 dsign = 0; | |
2197 #endif | |
2198 break; | |
2199 } | |
2200 } | |
2201 else if (!(word0(rv) & Bndry_mask) && !word1(rv)) { | |
2202 drop_down: | |
2203 /* boundary case -- decrement exponent */ | |
2204 #ifdef Sudden_Underflow /*{{*/ | |
2205 L = word0(rv) & Exp_mask; | |
2206 #ifdef IBM | |
2207 if (L < Exp_msk1) | |
2208 #else | |
2209 #ifdef Avoid_Underflow | |
2210 if (L <= (scale ? (2*P+1)*Exp_msk1 : Exp_msk1)) | |
2211 #else | |
2212 if (L <= Exp_msk1) | |
2213 #endif /*Avoid_Underflow*/ | |
2214 #endif /*IBM*/ | |
2215 goto undfl; | |
2216 L -= Exp_msk1; | |
2217 #else /*Sudden_Underflow}{*/ | |
2218 #ifdef Avoid_Underflow | |
2219 if (scale) { | |
2220 L = word0(rv) & Exp_mask; | |
2221 if (L <= (2*P+1)*Exp_msk1) { | |
2222 if (L > (P+2)*Exp_msk1) | |
2223 /* round even ==> */ | |
2224 /* accept rv */ | |
2225 break; | |
2226 /* rv = smallest denormal */ | |
2227 goto undfl; | |
2228 } | |
2229 } | |
2230 #endif /*Avoid_Underflow*/ | |
2231 L = (word0(rv) & Exp_mask) - Exp_msk1; | |
2232 #endif /*Sudden_Underflow}}*/ | |
2233 word0(rv) = L | Bndry_mask1; | |
2234 word1(rv) = 0xffffffff; | |
2235 #ifdef IBM | |
2236 goto cont; | |
2237 #else | |
2238 break; | |
2239 #endif | |
2240 } | |
2241 #ifndef ROUND_BIASED | |
2242 if (!(word1(rv) & LSB)) | |
2243 break; | |
2244 #endif | |
2245 if (dsign) | |
2246 dval(rv) += ulp(dval(rv)); | |
2247 #ifndef ROUND_BIASED | |
2248 else { | |
2249 dval(rv) -= ulp(dval(rv)); | |
2250 #ifndef Sudden_Underflow | |
2251 if (!dval(rv)) | |
2252 goto undfl; | |
2253 #endif | |
2254 } | |
2255 #ifdef Avoid_Underflow | |
2256 dsign = 1 - dsign; | |
2257 #endif | |
2258 #endif | |
2259 break; | |
2260 } | |
2261 if ((aadj = ratio(delta, bs)) <= 2.) { | |
2262 if (dsign) | |
2263 aadj = aadj1 = 1.; | |
2264 else if (word1(rv) || word0(rv) & Bndry_mask) { | |
2265 #ifndef Sudden_Underflow | |
2266 if (word1(rv) == Tiny1 && !word0(rv)) | |
2267 goto undfl; | |
2268 #endif | |
2269 aadj = 1.; | |
2270 aadj1 = -1.; | |
2271 } | |
2272 else { | |
2273 /* special case -- power of FLT_RADIX to be */ | |
2274 /* rounded down... */ | |
2275 | |
2276 if (aadj < 2./FLT_RADIX) | |
2277 aadj = 1./FLT_RADIX; | |
2278 else | |
2279 aadj *= 0.5; | |
2280 aadj1 = -aadj; | |
2281 } | |
2282 } | |
2283 else { | |
2284 aadj *= 0.5; | |
2285 aadj1 = dsign ? aadj : -aadj; | |
2286 #ifdef Check_FLT_ROUNDS | |
2287 switch(Rounding) { | |
2288 case 2: /* towards +infinity */ | |
2289 aadj1 -= 0.5; | |
2290 break; | |
2291 case 0: /* towards 0 */ | |
2292 case 3: /* towards -infinity */ | |
2293 aadj1 += 0.5; | |
2294 } | |
2295 #else | |
2296 if (Flt_Rounds == 0) | |
2297 aadj1 += 0.5; | |
2298 #endif /*Check_FLT_ROUNDS*/ | |
2299 } | |
2300 y = word0(rv) & Exp_mask; | |
2301 | |
2302 /* Check for overflow */ | |
2303 | |
2304 if (y == Exp_msk1*(DBL_MAX_EXP+Bias-1)) { | |
2305 dval(rv0) = dval(rv); | |
2306 word0(rv) -= P*Exp_msk1; | |
2307 adj = aadj1 * ulp(dval(rv)); | |
2308 dval(rv) += adj; | |
2309 if ((word0(rv) & Exp_mask) >= | |
2310 Exp_msk1*(DBL_MAX_EXP+Bias-P)) { | |
2311 if (word0(rv0) == Big0 && word1(rv0) == Big1) | |
2312 goto ovfl; | |
2313 word0(rv) = Big0; | |
2314 word1(rv) = Big1; | |
2315 goto cont; | |
2316 } | |
2317 else | |
2318 word0(rv) += P*Exp_msk1; | |
2319 } | |
2320 else { | |
2321 #ifdef Avoid_Underflow | |
2322 if (scale && y <= 2*P*Exp_msk1) { | |
2323 if (aadj <= 0x7fffffff) { | |
2324 if ((z = aadj) <= 0) | |
2325 z = 1; | |
2326 aadj = z; | |
2327 aadj1 = dsign ? aadj : -aadj; | |
2328 } | |
2329 word0(aadj1) += (2*P+1)*Exp_msk1 - y; | |
2330 } | |
2331 adj = aadj1 * ulp(dval(rv)); | |
2332 dval(rv) += adj; | |
2333 #else | |
2334 #ifdef Sudden_Underflow | |
2335 if ((word0(rv) & Exp_mask) <= P*Exp_msk1) { | |
2336 dval(rv0) = dval(rv); | |
2337 word0(rv) += P*Exp_msk1; | |
2338 adj = aadj1 * ulp(dval(rv)); | |
2339 dval(rv) += adj; | |
2340 #ifdef IBM | |
2341 if ((word0(rv) & Exp_mask) < P*Exp_msk1) | |
2342 #else | |
2343 if ((word0(rv) & Exp_mask) <= P*Exp_msk1) | |
2344 #endif | |
2345 { | |
2346 if (word0(rv0) == Tiny0 | |
2347 && word1(rv0) == Tiny1) | |
2348 goto undfl; | |
2349 word0(rv) = Tiny0; | |
2350 word1(rv) = Tiny1; | |
2351 goto cont; | |
2352 } | |
2353 else | |
2354 word0(rv) -= P*Exp_msk1; | |
2355 } | |
2356 else { | |
2357 adj = aadj1 * ulp(dval(rv)); | |
2358 dval(rv) += adj; | |
2359 } | |
2360 #else /*Sudden_Underflow*/ | |
2361 /* Compute adj so that the IEEE rounding rules will | |
2362 * correctly round rv + adj in some half-way cases. | |
2363 * If rv * ulp(rv) is denormalized (i.e., | |
2364 * y <= (P-1)*Exp_msk1), we must adjust aadj to avoid | |
2365 * trouble from bits lost to denormalization; | |
2366 * example: 1.2e-307 . | |
2367 */ | |
2368 if (y <= (P-1)*Exp_msk1 && aadj > 1.) { | |
2369 aadj1 = (double)(int)(aadj + 0.5); | |
2370 if (!dsign) | |
2371 aadj1 = -aadj1; | |
2372 } | |
2373 adj = aadj1 * ulp(dval(rv)); | |
2374 dval(rv) += adj; | |
2375 #endif /*Sudden_Underflow*/ | |
2376 #endif /*Avoid_Underflow*/ | |
2377 } | |
2378 z = word0(rv) & Exp_mask; | |
2379 #ifndef SET_INEXACT | |
2380 #ifdef Avoid_Underflow | |
2381 if (!scale) | |
2382 #endif | |
2383 if (y == z) { | |
2384 /* Can we stop now? */ | |
2385 L = (Long)aadj; | |
2386 aadj -= L; | |
2387 /* The tolerances below are conservative. */ | |
2388 if (dsign || word1(rv) || word0(rv) & Bndry_mask) { | |
2389 if (aadj < .4999999 || aadj > .5000001) | |
2390 break; | |
2391 } | |
2392 else if (aadj < .4999999/FLT_RADIX) | |
2393 break; | |
2394 } | |
2395 #endif | |
2396 cont: | |
2397 Bfree(bb); | |
2398 Bfree(bd); | |
2399 Bfree(bs); | |
2400 Bfree(delta); | |
2401 } | |
2402 #ifdef SET_INEXACT | |
2403 if (inexact) { | |
2404 if (!oldinexact) { | |
2405 word0(rv0) = Exp_1 + (70 << Exp_shift); | |
2406 word1(rv0) = 0; | |
2407 dval(rv0) += 1.; | |
2408 } | |
2409 } | |
2410 else if (!oldinexact) | |
2411 clear_inexact(); | |
2412 #endif | |
2413 #ifdef Avoid_Underflow | |
2414 if (scale) { | |
2415 word0(rv0) = Exp_1 - 2*P*Exp_msk1; | |
2416 word1(rv0) = 0; | |
2417 dval(rv) *= dval(rv0); | |
2418 #ifndef NO_ERRNO | |
2419 /* try to avoid the bug of testing an 8087 register value */ | |
2420 #ifdef IEEE_Arith | |
2421 if (!(word0(rv) & Exp_mask)) | |
2422 #else | |
2423 if (word0(rv) == 0 && word1(rv) == 0) | |
2424 #endif | |
2425 errno = ERANGE; | |
2426 #endif | |
2427 } | |
2428 #endif /* Avoid_Underflow */ | |
2429 #ifdef SET_INEXACT | |
2430 if (inexact && !(word0(rv) & Exp_mask)) { | |
2431 /* set underflow bit */ | |
2432 dval(rv0) = 1e-300; | |
2433 dval(rv0) *= dval(rv0); | |
2434 } | |
2435 #endif | |
2436 retfree: | |
2437 Bfree(bb); | |
2438 Bfree(bd); | |
2439 Bfree(bs); | |
2440 Bfree(bd0); | |
2441 Bfree(delta); | |
2442 ret: | |
2443 if (se) | |
2444 *se = (char *)s; | |
2445 return sign ? -dval(rv) : dval(rv); | |
2446 } | |
2447 | |
2448 static int | |
2449 quorem | |
2450 #ifdef KR_headers | |
2451 (b, S) Bigint *b, *S; | |
2452 #else | |
2453 (Bigint *b, Bigint *S) | |
2454 #endif | |
2455 { | |
2456 int n; | |
2457 ULong *bx, *bxe, q, *sx, *sxe; | |
2458 #ifdef ULLong | |
2459 ULLong borrow, carry, y, ys; | |
2460 #else | |
2461 ULong borrow, carry, y, ys; | |
2462 #ifdef Pack_32 | |
2463 ULong si, z, zs; | |
2464 #endif | |
2465 #endif | |
2466 | |
2467 n = S->wds; | |
2468 #ifdef DEBUG | |
2469 /*debug*/ if (b->wds > n) | |
2470 /*debug*/ Bug("oversize b in quorem"); | |
2471 #endif | |
2472 if (b->wds < n) | |
2473 return 0; | |
2474 sx = S->x; | |
2475 sxe = sx + --n; | |
2476 bx = b->x; | |
2477 bxe = bx + n; | |
2478 q = *bxe / (*sxe + 1); /* ensure q <= true quotient */ | |
2479 #ifdef DEBUG | |
2480 /*debug*/ if (q > 9) | |
2481 /*debug*/ Bug("oversized quotient in quorem"); | |
2482 #endif | |
2483 if (q) { | |
2484 borrow = 0; | |
2485 carry = 0; | |
2486 do { | |
2487 #ifdef ULLong | |
2488 ys = *sx++ * (ULLong)q + carry; | |
2489 carry = ys >> 32; | |
2490 y = *bx - (ys & FFFFFFFF) - borrow; | |
2491 borrow = y >> 32 & (ULong)1; | |
2492 *bx++ = y & FFFFFFFF; | |
2493 #else | |
2494 #ifdef Pack_32 | |
2495 si = *sx++; | |
2496 ys = (si & 0xffff) * q + carry; | |
2497 zs = (si >> 16) * q + (ys >> 16); | |
2498 carry = zs >> 16; | |
2499 y = (*bx & 0xffff) - (ys & 0xffff) - borrow; | |
2500 borrow = (y & 0x10000) >> 16; | |
2501 z = (*bx >> 16) - (zs & 0xffff) - borrow; | |
2502 borrow = (z & 0x10000) >> 16; | |
2503 Storeinc(bx, z, y); | |
2504 #else | |
2505 ys = *sx++ * q + carry; | |
2506 carry = ys >> 16; | |
2507 y = *bx - (ys & 0xffff) - borrow; | |
2508 borrow = (y & 0x10000) >> 16; | |
2509 *bx++ = y & 0xffff; | |
2510 #endif | |
2511 #endif | |
2512 } | |
2513 while(sx <= sxe); | |
2514 if (!*bxe) { | |
2515 bx = b->x; | |
2516 while(--bxe > bx && !*bxe) | |
2517 --n; | |
2518 b->wds = n; | |
2519 } | |
2520 } | |
2521 if (cmp(b, S) >= 0) { | |
2522 q++; | |
2523 borrow = 0; | |
2524 carry = 0; | |
2525 bx = b->x; | |
2526 sx = S->x; | |
2527 do { | |
2528 #ifdef ULLong | |
2529 ys = *sx++ + carry; | |
2530 carry = ys >> 32; | |
2531 y = *bx - (ys & FFFFFFFF) - borrow; | |
2532 borrow = y >> 32 & (ULong)1; | |
2533 *bx++ = y & FFFFFFFF; | |
2534 #else | |
2535 #ifdef Pack_32 | |
2536 si = *sx++; | |
2537 ys = (si & 0xffff) + carry; | |
2538 zs = (si >> 16) + (ys >> 16); | |
2539 carry = zs >> 16; | |
2540 y = (*bx & 0xffff) - (ys & 0xffff) - borrow; | |
2541 borrow = (y & 0x10000) >> 16; | |
2542 z = (*bx >> 16) - (zs & 0xffff) - borrow; | |
2543 borrow = (z & 0x10000) >> 16; | |
2544 Storeinc(bx, z, y); | |
2545 #else | |
2546 ys = *sx++ + carry; | |
2547 carry = ys >> 16; | |
2548 y = *bx - (ys & 0xffff) - borrow; | |
2549 borrow = (y & 0x10000) >> 16; | |
2550 *bx++ = y & 0xffff; | |
2551 #endif | |
2552 #endif | |
2553 } | |
2554 while(sx <= sxe); | |
2555 bx = b->x; | |
2556 bxe = bx + n; | |
2557 if (!*bxe) { | |
2558 while(--bxe > bx && !*bxe) | |
2559 --n; | |
2560 b->wds = n; | |
2561 } | |
2562 } | |
2563 return q; | |
2564 } | |
2565 | |
2566 #ifndef MULTIPLE_THREADS | |
2567 static char *dtoa_result; | |
2568 #endif | |
2569 | |
2570 static char * | |
2571 #ifdef KR_headers | |
2572 rv_alloc(i) int i; | |
2573 #else | |
2574 rv_alloc(int i) | |
2575 #endif | |
2576 { | |
2577 int j, k, *r; | |
2578 | |
2579 j = sizeof(ULong); | |
2580 for(k = 0; | |
2581 sizeof(Bigint) - sizeof(ULong) - sizeof(int) + j <= i; | |
2582 j <<= 1) | |
2583 k++; | |
2584 r = (int*)Balloc(k); | |
2585 *r = k; | |
2586 return | |
2587 #ifndef MULTIPLE_THREADS | |
2588 dtoa_result = | |
2589 #endif | |
2590 (char *)(r+1); | |
2591 } | |
2592 | |
2593 static char * | |
2594 #ifdef KR_headers | |
2595 nrv_alloc(s, rve, n) char *s, **rve; int n; | |
2596 #else | |
2597 nrv_alloc(char *s, char **rve, int n) | |
2598 #endif | |
2599 { | |
2600 char *rv, *t; | |
2601 | |
2602 t = rv = rv_alloc(n); | |
2603 while(*t = *s++) t++; | |
2604 if (rve) | |
2605 *rve = t; | |
2606 return rv; | |
2607 } | |
2608 | |
2609 /* freedtoa(s) must be used to free values s returned by dtoa | |
2610 * when MULTIPLE_THREADS is #defined. It should be used in all cases, | |
2611 * but for consistency with earlier versions of dtoa, it is optional | |
2612 * when MULTIPLE_THREADS is not defined. | |
2613 */ | |
2614 | |
2615 void | |
2616 #ifdef KR_headers | |
2617 freedtoa(s) char *s; | |
2618 #else | |
2619 freedtoa(char *s) | |
2620 #endif | |
2621 { | |
2622 Bigint *b = (Bigint *)((int *)s - 1); | |
2623 b->maxwds = 1 << (b->k = *(int*)b); | |
2624 Bfree(b); | |
2625 #ifndef MULTIPLE_THREADS | |
2626 if (s == dtoa_result) | |
2627 dtoa_result = 0; | |
2628 #endif | |
2629 } | |
2630 | |
2631 /* dtoa for IEEE arithmetic (dmg): convert double to ASCII string. | |
2632 * | |
2633 * Inspired by "How to Print Floating-Point Numbers Accurately" by | |
2634 * Guy L. Steele, Jr. and Jon L. White [Proc. ACM SIGPLAN '90, pp. 112-126]. | |
2635 * | |
2636 * Modifications: | |
2637 * 1. Rather than iterating, we use a simple numeric overestimate | |
2638 * to determine k = floor(log10(d)). We scale relevant | |
2639 * quantities using O(log2(k)) rather than O(k) multiplications. | |
2640 * 2. For some modes > 2 (corresponding to ecvt and fcvt), we don't | |
2641 * try to generate digits strictly left to right. Instead, we | |
2642 * compute with fewer bits and propagate the carry if necessary | |
2643 * when rounding the final digit up. This is often faster. | |
2644 * 3. Under the assumption that input will be rounded nearest, | |
2645 * mode 0 renders 1e23 as 1e23 rather than 9.999999999999999e22. | |
2646 * That is, we allow equality in stopping tests when the | |
2647 * round-nearest rule will give the same floating-point value | |
2648 * as would satisfaction of the stopping test with strict | |
2649 * inequality. | |
2650 * 4. We remove common factors of powers of 2 from relevant | |
2651 * quantities. | |
2652 * 5. When converting floating-point integers less than 1e16, | |
2653 * we use floating-point arithmetic rather than resorting | |
2654 * to multiple-precision integers. | |
2655 * 6. When asked to produce fewer than 15 digits, we first try | |
2656 * to get by with floating-point arithmetic; we resort to | |
2657 * multiple-precision integer arithmetic only if we cannot | |
2658 * guarantee that the floating-point calculation has given | |
2659 * the correctly rounded result. For k requested digits and | |
2660 * "uniformly" distributed input, the probability is | |
2661 * something like 10^(k-15) that we must resort to the Long | |
2662 * calculation. | |
2663 */ | |
2664 | |
2665 char * | |
2666 dtoa | |
2667 #ifdef KR_headers | |
2668 (d, mode, ndigits, decpt, sign, rve) | |
2669 double d; int mode, ndigits, *decpt, *sign; char **rve; | |
2670 #else | |
2671 (double d, int mode, int ndigits, int *decpt, int *sign, char **rve) | |
2672 #endif | |
2673 { | |
2674 /* Arguments ndigits, decpt, sign are similar to those | |
2675 of ecvt and fcvt; trailing zeros are suppressed from | |
2676 the returned string. If not null, *rve is set to point | |
2677 to the end of the return value. If d is +-Infinity or NaN, | |
2678 then *decpt is set to 9999. | |
2679 | |
2680 mode: | |
2681 0 ==> shortest string that yields d when read in | |
2682 and rounded to nearest. | |
2683 1 ==> like 0, but with Steele & White stopping rule; | |
2684 e.g. with IEEE P754 arithmetic , mode 0 gives | |
2685 1e23 whereas mode 1 gives 9.999999999999999e22. | |
2686 2 ==> max(1,ndigits) significant digits. This gives a | |
2687 return value similar to that of ecvt, except | |
2688 that trailing zeros are suppressed. | |
2689 3 ==> through ndigits past the decimal point. This | |
2690 gives a return value similar to that from fcvt, | |
2691 except that trailing zeros are suppressed, and | |
2692 ndigits can be negative. | |
2693 4,5 ==> similar to 2 and 3, respectively, but (in | |
2694 round-nearest mode) with the tests of mode 0 to | |
2695 possibly return a shorter string that rounds to d. | |
2696 With IEEE arithmetic and compilation with | |
2697 -DHonor_FLT_ROUNDS, modes 4 and 5 behave the same | |
2698 as modes 2 and 3 when FLT_ROUNDS != 1. | |
2699 6-9 ==> Debugging modes similar to mode - 4: don't try | |
2700 fast floating-point estimate (if applicable). | |
2701 | |
2702 Values of mode other than 0-9 are treated as mode 0. | |
2703 | |
2704 Sufficient space is allocated to the return value | |
2705 to hold the suppressed trailing zeros. | |
2706 */ | |
2707 | |
2708 int bbits, b2, b5, be, dig, i, ieps, ilim, ilim0, ilim1, | |
2709 j, j1, k, k0, k_check, leftright, m2, m5, s2, s5, | |
2710 spec_case, try_quick; | |
2711 Long L; | |
2712 #ifndef Sudden_Underflow | |
2713 int denorm; | |
2714 ULong x; | |
2715 #endif | |
2716 Bigint *b, *b1, *delta, *mlo, *mhi, *S; | |
2717 double d2, ds, eps; | |
2718 char *s, *s0; | |
2719 #ifdef SET_INEXACT | |
2720 int inexact, oldinexact; | |
2721 #endif | |
2722 #ifdef Honor_FLT_ROUNDS /*{*/ | |
2723 int Rounding; | |
2724 #ifdef Trust_FLT_ROUNDS /*{{ only define this if FLT_ROUNDS really works! */ | |
2725 Rounding = Flt_Rounds; | |
2726 #else /*}{*/ | |
2727 Rounding = 1; | |
2728 switch(fegetround()) { | |
2729 case FE_TOWARDZERO: Rounding = 0; break; | |
2730 case FE_UPWARD: Rounding = 2; break; | |
2731 case FE_DOWNWARD: Rounding = 3; | |
2732 } | |
2733 #endif /*}}*/ | |
2734 #endif /*}*/ | |
2735 | |
2736 #ifndef MULTIPLE_THREADS | |
2737 if (dtoa_result) { | |
2738 freedtoa(dtoa_result); | |
2739 dtoa_result = 0; | |
2740 } | |
2741 #endif | |
2742 | |
2743 if (word0(d) & Sign_bit) { | |
2744 /* set sign for everything, including 0's and NaNs */ | |
2745 *sign = 1; | |
2746 word0(d) &= ~Sign_bit; /* clear sign bit */ | |
2747 } | |
2748 else | |
2749 *sign = 0; | |
2750 | |
2751 #if defined(IEEE_Arith) + defined(VAX) | |
2752 #ifdef IEEE_Arith | |
2753 if ((word0(d) & Exp_mask) == Exp_mask) | |
2754 #else | |
2755 if (word0(d) == 0x8000) | |
2756 #endif | |
2757 { | |
2758 /* Infinity or NaN */ | |
2759 *decpt = 9999; | |
2760 #ifdef IEEE_Arith | |
2761 if (!word1(d) && !(word0(d) & 0xfffff)) | |
2762 return nrv_alloc("Infinity", rve, 8); | |
2763 #endif | |
2764 return nrv_alloc("NaN", rve, 3); | |
2765 } | |
2766 #endif | |
2767 #ifdef IBM | |
2768 dval(d) += 0; /* normalize */ | |
2769 #endif | |
2770 if (!dval(d)) { | |
2771 *decpt = 1; | |
2772 return nrv_alloc("0", rve, 1); | |
2773 } | |
2774 | |
2775 #ifdef SET_INEXACT | |
2776 try_quick = oldinexact = get_inexact(); | |
2777 inexact = 1; | |
2778 #endif | |
2779 #ifdef Honor_FLT_ROUNDS | |
2780 if (Rounding >= 2) { | |
2781 if (*sign) | |
2782 Rounding = Rounding == 2 ? 0 : 2; | |
2783 else | |
2784 if (Rounding != 2) | |
2785 Rounding = 0; | |
2786 } | |
2787 #endif | |
2788 | |
2789 b = d2b(dval(d), &be, &bbits); | |
2790 #ifdef Sudden_Underflow | |
2791 i = (int)(word0(d) >> Exp_shift1 & (Exp_mask>>Exp_shift1)); | |
2792 #else | |
2793 if (i = (int)(word0(d) >> Exp_shift1 & (Exp_mask>>Exp_shift1))) { | |
2794 #endif | |
2795 dval(d2) = dval(d); | |
2796 word0(d2) &= Frac_mask1; | |
2797 word0(d2) |= Exp_11; | |
2798 #ifdef IBM | |
2799 if (j = 11 - hi0bits(word0(d2) & Frac_mask)) | |
2800 dval(d2) /= 1 << j; | |
2801 #endif | |
2802 | |
2803 /* log(x) ~=~ log(1.5) + (x-1.5)/1.5 | |
2804 * log10(x) = log(x) / log(10) | |
2805 * ~=~ log(1.5)/log(10) + (x-1.5)/(1.5*log(10)) | |
2806 * log10(d) = (i-Bias)*log(2)/log(10) + log10(d2) | |
2807 * | |
2808 * This suggests computing an approximation k to log10(d) by | |
2809 * | |
2810 * k = (i - Bias)*0.301029995663981 | |
2811 * + ( (d2-1.5)*0.289529654602168 + 0.176091259055681 ); | |
2812 * | |
2813 * We want k to be too large rather than too small. | |
2814 * The error in the first-order Taylor series approximation | |
2815 * is in our favor, so we just round up the constant enough | |
2816 * to compensate for any error in the multiplication of | |
2817 * (i - Bias) by 0.301029995663981; since |i - Bias| <= 1077, | |
2818 * and 1077 * 0.30103 * 2^-52 ~=~ 7.2e-14, | |
2819 * adding 1e-13 to the constant term more than suffices. | |
2820 * Hence we adjust the constant term to 0.1760912590558. | |
2821 * (We could get a more accurate k by invoking log10, | |
2822 * but this is probably not worthwhile.) | |
2823 */ | |
2824 | |
2825 i -= Bias; | |
2826 #ifdef IBM | |
2827 i <<= 2; | |
2828 i += j; | |
2829 #endif | |
2830 #ifndef Sudden_Underflow | |
2831 denorm = 0; | |
2832 } | |
2833 else { | |
2834 /* d is denormalized */ | |
2835 | |
2836 i = bbits + be + (Bias + (P-1) - 1); | |
2837 x = i > 32 ? word0(d) << 64 - i | word1(d) >> i - 32 | |
2838 : word1(d) << 32 - i; | |
2839 dval(d2) = x; | |
2840 word0(d2) -= 31*Exp_msk1; /* adjust exponent */ | |
2841 i -= (Bias + (P-1) - 1) + 1; | |
2842 denorm = 1; | |
2843 } | |
2844 #endif | |
2845 ds = (dval(d2)-1.5)*0.289529654602168 + 0.1760912590558 + i*0.3010299956
63981; | |
2846 k = (int)ds; | |
2847 if (ds < 0. && ds != k) | |
2848 k--; /* want k = floor(ds) */ | |
2849 k_check = 1; | |
2850 if (k >= 0 && k <= Ten_pmax) { | |
2851 if (dval(d) < tens[k]) | |
2852 k--; | |
2853 k_check = 0; | |
2854 } | |
2855 j = bbits - i - 1; | |
2856 if (j >= 0) { | |
2857 b2 = 0; | |
2858 s2 = j; | |
2859 } | |
2860 else { | |
2861 b2 = -j; | |
2862 s2 = 0; | |
2863 } | |
2864 if (k >= 0) { | |
2865 b5 = 0; | |
2866 s5 = k; | |
2867 s2 += k; | |
2868 } | |
2869 else { | |
2870 b2 -= k; | |
2871 b5 = -k; | |
2872 s5 = 0; | |
2873 } | |
2874 if (mode < 0 || mode > 9) | |
2875 mode = 0; | |
2876 | |
2877 #ifndef SET_INEXACT | |
2878 #ifdef Check_FLT_ROUNDS | |
2879 try_quick = Rounding == 1; | |
2880 #else | |
2881 try_quick = 1; | |
2882 #endif | |
2883 #endif /*SET_INEXACT*/ | |
2884 | |
2885 if (mode > 5) { | |
2886 mode -= 4; | |
2887 try_quick = 0; | |
2888 } | |
2889 leftright = 1; | |
2890 switch(mode) { | |
2891 case 0: | |
2892 case 1: | |
2893 ilim = ilim1 = -1; | |
2894 i = 18; | |
2895 ndigits = 0; | |
2896 break; | |
2897 case 2: | |
2898 leftright = 0; | |
2899 /* no break */ | |
2900 case 4: | |
2901 if (ndigits <= 0) | |
2902 ndigits = 1; | |
2903 ilim = ilim1 = i = ndigits; | |
2904 break; | |
2905 case 3: | |
2906 leftright = 0; | |
2907 /* no break */ | |
2908 case 5: | |
2909 i = ndigits + k + 1; | |
2910 ilim = i; | |
2911 ilim1 = i - 1; | |
2912 if (i <= 0) | |
2913 i = 1; | |
2914 } | |
2915 s = s0 = rv_alloc(i); | |
2916 | |
2917 #ifdef Honor_FLT_ROUNDS | |
2918 if (mode > 1 && Rounding != 1) | |
2919 leftright = 0; | |
2920 #endif | |
2921 | |
2922 if (ilim >= 0 && ilim <= Quick_max && try_quick) { | |
2923 | |
2924 /* Try to get by with floating-point arithmetic. */ | |
2925 | |
2926 i = 0; | |
2927 dval(d2) = dval(d); | |
2928 k0 = k; | |
2929 ilim0 = ilim; | |
2930 ieps = 2; /* conservative */ | |
2931 if (k > 0) { | |
2932 ds = tens[k&0xf]; | |
2933 j = k >> 4; | |
2934 if (j & Bletch) { | |
2935 /* prevent overflows */ | |
2936 j &= Bletch - 1; | |
2937 dval(d) /= bigtens[n_bigtens-1]; | |
2938 ieps++; | |
2939 } | |
2940 for(; j; j >>= 1, i++) | |
2941 if (j & 1) { | |
2942 ieps++; | |
2943 ds *= bigtens[i]; | |
2944 } | |
2945 dval(d) /= ds; | |
2946 } | |
2947 else if (j1 = -k) { | |
2948 dval(d) *= tens[j1 & 0xf]; | |
2949 for(j = j1 >> 4; j; j >>= 1, i++) | |
2950 if (j & 1) { | |
2951 ieps++; | |
2952 dval(d) *= bigtens[i]; | |
2953 } | |
2954 } | |
2955 if (k_check && dval(d) < 1. && ilim > 0) { | |
2956 if (ilim1 <= 0) | |
2957 goto fast_failed; | |
2958 ilim = ilim1; | |
2959 k--; | |
2960 dval(d) *= 10.; | |
2961 ieps++; | |
2962 } | |
2963 dval(eps) = ieps*dval(d) + 7.; | |
2964 word0(eps) -= (P-1)*Exp_msk1; | |
2965 if (ilim == 0) { | |
2966 S = mhi = 0; | |
2967 dval(d) -= 5.; | |
2968 if (dval(d) > dval(eps)) | |
2969 goto one_digit; | |
2970 if (dval(d) < -dval(eps)) | |
2971 goto no_digits; | |
2972 goto fast_failed; | |
2973 } | |
2974 #ifndef No_leftright | |
2975 if (leftright) { | |
2976 /* Use Steele & White method of only | |
2977 * generating digits needed. | |
2978 */ | |
2979 dval(eps) = 0.5/tens[ilim-1] - dval(eps); | |
2980 for(i = 0;;) { | |
2981 L = dval(d); | |
2982 dval(d) -= L; | |
2983 *s++ = '0' + (int)L; | |
2984 if (dval(d) < dval(eps)) | |
2985 goto ret1; | |
2986 if (1. - dval(d) < dval(eps)) | |
2987 goto bump_up; | |
2988 if (++i >= ilim) | |
2989 break; | |
2990 dval(eps) *= 10.; | |
2991 dval(d) *= 10.; | |
2992 } | |
2993 } | |
2994 else { | |
2995 #endif | |
2996 /* Generate ilim digits, then fix them up. */ | |
2997 dval(eps) *= tens[ilim-1]; | |
2998 for(i = 1;; i++, dval(d) *= 10.) { | |
2999 L = (Long)(dval(d)); | |
3000 if (!(dval(d) -= L)) | |
3001 ilim = i; | |
3002 *s++ = '0' + (int)L; | |
3003 if (i == ilim) { | |
3004 if (dval(d) > 0.5 + dval(eps)) | |
3005 goto bump_up; | |
3006 else if (dval(d) < 0.5 - dval(eps)) { | |
3007 while(*--s == '0'); | |
3008 s++; | |
3009 goto ret1; | |
3010 } | |
3011 break; | |
3012 } | |
3013 } | |
3014 #ifndef No_leftright | |
3015 } | |
3016 #endif | |
3017 fast_failed: | |
3018 s = s0; | |
3019 dval(d) = dval(d2); | |
3020 k = k0; | |
3021 ilim = ilim0; | |
3022 } | |
3023 | |
3024 /* Do we have a "small" integer? */ | |
3025 | |
3026 if (be >= 0 && k <= Int_max) { | |
3027 /* Yes. */ | |
3028 ds = tens[k]; | |
3029 if (ndigits < 0 && ilim <= 0) { | |
3030 S = mhi = 0; | |
3031 if (ilim < 0 || dval(d) <= 5*ds) | |
3032 goto no_digits; | |
3033 goto one_digit; | |
3034 } | |
3035 for(i = 1;; i++, dval(d) *= 10.) { | |
3036 L = (Long)(dval(d) / ds); | |
3037 dval(d) -= L*ds; | |
3038 #ifdef Check_FLT_ROUNDS | |
3039 /* If FLT_ROUNDS == 2, L will usually be high by 1 */ | |
3040 if (dval(d) < 0) { | |
3041 L--; | |
3042 dval(d) += ds; | |
3043 } | |
3044 #endif | |
3045 *s++ = '0' + (int)L; | |
3046 if (!dval(d)) { | |
3047 #ifdef SET_INEXACT | |
3048 inexact = 0; | |
3049 #endif | |
3050 break; | |
3051 } | |
3052 if (i == ilim) { | |
3053 #ifdef Honor_FLT_ROUNDS | |
3054 if (mode > 1) | |
3055 switch(Rounding) { | |
3056 case 0: goto ret1; | |
3057 case 2: goto bump_up; | |
3058 } | |
3059 #endif | |
3060 dval(d) += dval(d); | |
3061 if (dval(d) > ds || dval(d) == ds && L & 1) { | |
3062 bump_up: | |
3063 while(*--s == '9') | |
3064 if (s == s0) { | |
3065 k++; | |
3066 *s = '0'; | |
3067 break; | |
3068 } | |
3069 ++*s++; | |
3070 } | |
3071 break; | |
3072 } | |
3073 } | |
3074 goto ret1; | |
3075 } | |
3076 | |
3077 m2 = b2; | |
3078 m5 = b5; | |
3079 mhi = mlo = 0; | |
3080 if (leftright) { | |
3081 i = | |
3082 #ifndef Sudden_Underflow | |
3083 denorm ? be + (Bias + (P-1) - 1 + 1) : | |
3084 #endif | |
3085 #ifdef IBM | |
3086 1 + 4*P - 3 - bbits + ((bbits + be - 1) & 3); | |
3087 #else | |
3088 1 + P - bbits; | |
3089 #endif | |
3090 b2 += i; | |
3091 s2 += i; | |
3092 mhi = i2b(1); | |
3093 } | |
3094 if (m2 > 0 && s2 > 0) { | |
3095 i = m2 < s2 ? m2 : s2; | |
3096 b2 -= i; | |
3097 m2 -= i; | |
3098 s2 -= i; | |
3099 } | |
3100 if (b5 > 0) { | |
3101 if (leftright) { | |
3102 if (m5 > 0) { | |
3103 mhi = pow5mult(mhi, m5); | |
3104 b1 = mult(mhi, b); | |
3105 Bfree(b); | |
3106 b = b1; | |
3107 } | |
3108 if (j = b5 - m5) | |
3109 b = pow5mult(b, j); | |
3110 } | |
3111 else | |
3112 b = pow5mult(b, b5); | |
3113 } | |
3114 S = i2b(1); | |
3115 if (s5 > 0) | |
3116 S = pow5mult(S, s5); | |
3117 | |
3118 /* Check for special case that d is a normalized power of 2. */ | |
3119 | |
3120 spec_case = 0; | |
3121 if ((mode < 2 || leftright) | |
3122 #ifdef Honor_FLT_ROUNDS | |
3123 && Rounding == 1 | |
3124 #endif | |
3125 ) { | |
3126 if (!word1(d) && !(word0(d) & Bndry_mask) | |
3127 #ifndef Sudden_Underflow | |
3128 && word0(d) & (Exp_mask & ~Exp_msk1) | |
3129 #endif | |
3130 ) { | |
3131 /* The special case */ | |
3132 b2 += Log2P; | |
3133 s2 += Log2P; | |
3134 spec_case = 1; | |
3135 } | |
3136 } | |
3137 | |
3138 /* Arrange for convenient computation of quotients: | |
3139 * shift left if necessary so divisor has 4 leading 0 bits. | |
3140 * | |
3141 * Perhaps we should just compute leading 28 bits of S once | |
3142 * and for all and pass them and a shift to quorem, so it | |
3143 * can do shifts and ors to compute the numerator for q. | |
3144 */ | |
3145 #ifdef Pack_32 | |
3146 if (i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0x1f) | |
3147 i = 32 - i; | |
3148 #else | |
3149 if (i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0xf) | |
3150 i = 16 - i; | |
3151 #endif | |
3152 if (i > 4) { | |
3153 i -= 4; | |
3154 b2 += i; | |
3155 m2 += i; | |
3156 s2 += i; | |
3157 } | |
3158 else if (i < 4) { | |
3159 i += 28; | |
3160 b2 += i; | |
3161 m2 += i; | |
3162 s2 += i; | |
3163 } | |
3164 if (b2 > 0) | |
3165 b = lshift(b, b2); | |
3166 if (s2 > 0) | |
3167 S = lshift(S, s2); | |
3168 if (k_check) { | |
3169 if (cmp(b,S) < 0) { | |
3170 k--; | |
3171 b = multadd(b, 10, 0); /* we botched the k estimate */ | |
3172 if (leftright) | |
3173 mhi = multadd(mhi, 10, 0); | |
3174 ilim = ilim1; | |
3175 } | |
3176 } | |
3177 if (ilim <= 0 && (mode == 3 || mode == 5)) { | |
3178 if (ilim < 0 || cmp(b,S = multadd(S,5,0)) <= 0) { | |
3179 /* no digits, fcvt style */ | |
3180 no_digits: | |
3181 k = -1 - ndigits; | |
3182 goto ret; | |
3183 } | |
3184 one_digit: | |
3185 *s++ = '1'; | |
3186 k++; | |
3187 goto ret; | |
3188 } | |
3189 if (leftright) { | |
3190 if (m2 > 0) | |
3191 mhi = lshift(mhi, m2); | |
3192 | |
3193 /* Compute mlo -- check for special case | |
3194 * that d is a normalized power of 2. | |
3195 */ | |
3196 | |
3197 mlo = mhi; | |
3198 if (spec_case) { | |
3199 mhi = Balloc(mhi->k); | |
3200 Bcopy(mhi, mlo); | |
3201 mhi = lshift(mhi, Log2P); | |
3202 } | |
3203 | |
3204 for(i = 1;;i++) { | |
3205 dig = quorem(b,S) + '0'; | |
3206 /* Do we yet have the shortest decimal string | |
3207 * that will round to d? | |
3208 */ | |
3209 j = cmp(b, mlo); | |
3210 delta = diff(S, mhi); | |
3211 j1 = delta->sign ? 1 : cmp(b, delta); | |
3212 Bfree(delta); | |
3213 #ifndef ROUND_BIASED | |
3214 if (j1 == 0 && mode != 1 && !(word1(d) & 1) | |
3215 #ifdef Honor_FLT_ROUNDS | |
3216 && Rounding >= 1 | |
3217 #endif | |
3218 ) { | |
3219 if (dig == '9') | |
3220 goto round_9_up; | |
3221 if (j > 0) | |
3222 dig++; | |
3223 #ifdef SET_INEXACT | |
3224 else if (!b->x[0] && b->wds <= 1) | |
3225 inexact = 0; | |
3226 #endif | |
3227 *s++ = dig; | |
3228 goto ret; | |
3229 } | |
3230 #endif | |
3231 if (j < 0 || j == 0 && mode != 1 | |
3232 #ifndef ROUND_BIASED | |
3233 && !(word1(d) & 1) | |
3234 #endif | |
3235 ) { | |
3236 if (!b->x[0] && b->wds <= 1) { | |
3237 #ifdef SET_INEXACT | |
3238 inexact = 0; | |
3239 #endif | |
3240 goto accept_dig; | |
3241 } | |
3242 #ifdef Honor_FLT_ROUNDS | |
3243 if (mode > 1) | |
3244 switch(Rounding) { | |
3245 case 0: goto accept_dig; | |
3246 case 2: goto keep_dig; | |
3247 } | |
3248 #endif /*Honor_FLT_ROUNDS*/ | |
3249 if (j1 > 0) { | |
3250 b = lshift(b, 1); | |
3251 j1 = cmp(b, S); | |
3252 if ((j1 > 0 || j1 == 0 && dig & 1) | |
3253 && dig++ == '9') | |
3254 goto round_9_up; | |
3255 } | |
3256 accept_dig: | |
3257 *s++ = dig; | |
3258 goto ret; | |
3259 } | |
3260 if (j1 > 0) { | |
3261 #ifdef Honor_FLT_ROUNDS | |
3262 if (!Rounding) | |
3263 goto accept_dig; | |
3264 #endif | |
3265 if (dig == '9') { /* possible if i == 1 */ | |
3266 round_9_up: | |
3267 *s++ = '9'; | |
3268 goto roundoff; | |
3269 } | |
3270 *s++ = dig + 1; | |
3271 goto ret; | |
3272 } | |
3273 #ifdef Honor_FLT_ROUNDS | |
3274 keep_dig: | |
3275 #endif | |
3276 *s++ = dig; | |
3277 if (i == ilim) | |
3278 break; | |
3279 b = multadd(b, 10, 0); | |
3280 if (mlo == mhi) | |
3281 mlo = mhi = multadd(mhi, 10, 0); | |
3282 else { | |
3283 mlo = multadd(mlo, 10, 0); | |
3284 mhi = multadd(mhi, 10, 0); | |
3285 } | |
3286 } | |
3287 } | |
3288 else | |
3289 for(i = 1;; i++) { | |
3290 *s++ = dig = quorem(b,S) + '0'; | |
3291 if (!b->x[0] && b->wds <= 1) { | |
3292 #ifdef SET_INEXACT | |
3293 inexact = 0; | |
3294 #endif | |
3295 goto ret; | |
3296 } | |
3297 if (i >= ilim) | |
3298 break; | |
3299 b = multadd(b, 10, 0); | |
3300 } | |
3301 | |
3302 /* Round off last digit */ | |
3303 | |
3304 #ifdef Honor_FLT_ROUNDS | |
3305 switch(Rounding) { | |
3306 case 0: goto trimzeros; | |
3307 case 2: goto roundoff; | |
3308 } | |
3309 #endif | |
3310 b = lshift(b, 1); | |
3311 j = cmp(b, S); | |
3312 if (j > 0 || j == 0 && dig & 1) { | |
3313 roundoff: | |
3314 while(*--s == '9') | |
3315 if (s == s0) { | |
3316 k++; | |
3317 *s++ = '1'; | |
3318 goto ret; | |
3319 } | |
3320 ++*s++; | |
3321 } | |
3322 else { | |
3323 trimzeros: | |
3324 while(*--s == '0'); | |
3325 s++; | |
3326 } | |
3327 ret: | |
3328 Bfree(S); | |
3329 if (mhi) { | |
3330 if (mlo && mlo != mhi) | |
3331 Bfree(mlo); | |
3332 Bfree(mhi); | |
3333 } | |
3334 ret1: | |
3335 #ifdef SET_INEXACT | |
3336 if (inexact) { | |
3337 if (!oldinexact) { | |
3338 word0(d) = Exp_1 + (70 << Exp_shift); | |
3339 word1(d) = 0; | |
3340 dval(d) += 1.; | |
3341 } | |
3342 } | |
3343 else if (!oldinexact) | |
3344 clear_inexact(); | |
3345 #endif | |
3346 Bfree(b); | |
3347 *s = 0; | |
3348 *decpt = k + 1; | |
3349 if (rve) | |
3350 *rve = s; | |
3351 return s0; | |
3352 } | |
3353 | |
3354 } // namespace dmg_fp | |
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