-
Notifications
You must be signed in to change notification settings - Fork 949
/
Copy pathdtoa.c
1626 lines (1508 loc) · 44 KB
/
dtoa.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Tiny float64 printing and parsing library
*
* Copyright (c) 2024 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <inttypes.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <sys/time.h>
#include <math.h>
#include <setjmp.h>
#include "cutils.h"
#include "dtoa.h"
/*
TODO:
- test n_digits=101 instead of 100
- simplify subnormal handling
- reduce max memory usage
- free format: could add shortcut if exact result
- use 64 bit limb_t when possible
- use another algorithm for free format dtoa in base 10 (ryu ?)
*/
#define USE_POW5_TABLE
/* use fast path to print small integers in free format */
#define USE_FAST_INT
#define LIMB_LOG2_BITS 5
#define LIMB_BITS (1 << LIMB_LOG2_BITS)
typedef int32_t slimb_t;
typedef uint32_t limb_t;
typedef uint64_t dlimb_t;
#define LIMB_DIGITS 9
#define JS_RADIX_MAX 36
#define DBIGNUM_LEN_MAX 52 /* ~ 2^(1072+53)*36^100 (dtoa) */
#define MANT_LEN_MAX 18 /* < 36^100 */
typedef intptr_t mp_size_t;
/* the represented number is sum(i, tab[i]*2^(LIMB_BITS * i)) */
typedef struct {
int len; /* >= 1 */
limb_t tab[];
} mpb_t;
static limb_t mp_add_ui(limb_t *tab, limb_t b, size_t n)
{
size_t i;
limb_t k, a;
k=b;
for(i=0;i<n;i++) {
if (k == 0)
break;
a = tab[i] + k;
k = (a < k);
tab[i] = a;
}
return k;
}
/* tabr[] = taba[] * b + l. Return the high carry */
static limb_t mp_mul1(limb_t *tabr, const limb_t *taba, limb_t n,
limb_t b, limb_t l)
{
limb_t i;
dlimb_t t;
for(i = 0; i < n; i++) {
t = (dlimb_t)taba[i] * (dlimb_t)b + l;
tabr[i] = t;
l = t >> LIMB_BITS;
}
return l;
}
/* WARNING: d must be >= 2^(LIMB_BITS-1) */
static inline limb_t udiv1norm_init(limb_t d)
{
limb_t a0, a1;
a1 = -d - 1;
a0 = -1;
return (((dlimb_t)a1 << LIMB_BITS) | a0) / d;
}
/* return the quotient and the remainder in '*pr'of 'a1*2^LIMB_BITS+a0
/ d' with 0 <= a1 < d. */
static inline limb_t udiv1norm(limb_t *pr, limb_t a1, limb_t a0,
limb_t d, limb_t d_inv)
{
limb_t n1m, n_adj, q, r, ah;
dlimb_t a;
n1m = ((slimb_t)a0 >> (LIMB_BITS - 1));
n_adj = a0 + (n1m & d);
a = (dlimb_t)d_inv * (a1 - n1m) + n_adj;
q = (a >> LIMB_BITS) + a1;
/* compute a - q * r and update q so that the remainder is between
0 and d - 1 */
a = ((dlimb_t)a1 << LIMB_BITS) | a0;
a = a - (dlimb_t)q * d - d;
ah = a >> LIMB_BITS;
q += 1 + ah;
r = (limb_t)a + (ah & d);
*pr = r;
return q;
}
static limb_t mp_div1(limb_t *tabr, const limb_t *taba, limb_t n,
limb_t b, limb_t r)
{
slimb_t i;
dlimb_t a1;
for(i = n - 1; i >= 0; i--) {
a1 = ((dlimb_t)r << LIMB_BITS) | taba[i];
tabr[i] = a1 / b;
r = a1 % b;
}
return r;
}
/* r = (a + high*B^n) >> shift. Return the remainder r (0 <= r < 2^shift).
1 <= shift <= LIMB_BITS - 1 */
static limb_t mp_shr(limb_t *tab_r, const limb_t *tab, mp_size_t n,
int shift, limb_t high)
{
mp_size_t i;
limb_t l, a;
assert(shift >= 1 && shift < LIMB_BITS);
l = high;
for(i = n - 1; i >= 0; i--) {
a = tab[i];
tab_r[i] = (a >> shift) | (l << (LIMB_BITS - shift));
l = a;
}
return l & (((limb_t)1 << shift) - 1);
}
/* r = (a << shift) + low. 1 <= shift <= LIMB_BITS - 1, 0 <= low <
2^shift. */
static limb_t mp_shl(limb_t *tab_r, const limb_t *tab, mp_size_t n,
int shift, limb_t low)
{
mp_size_t i;
limb_t l, a;
assert(shift >= 1 && shift < LIMB_BITS);
l = low;
for(i = 0; i < n; i++) {
a = tab[i];
tab_r[i] = (a << shift) | l;
l = (a >> (LIMB_BITS - shift));
}
return l;
}
static no_inline limb_t mp_div1norm(limb_t *tabr, const limb_t *taba, limb_t n,
limb_t b, limb_t r, limb_t b_inv, int shift)
{
slimb_t i;
if (shift != 0) {
r = (r << shift) | mp_shl(tabr, taba, n, shift, 0);
}
for(i = n - 1; i >= 0; i--) {
tabr[i] = udiv1norm(&r, r, taba[i], b, b_inv);
}
r >>= shift;
return r;
}
static __maybe_unused void mpb_dump(const char *str, const mpb_t *a)
{
int i;
printf("%s= 0x", str);
for(i = a->len - 1; i >= 0; i--) {
printf("%08x", a->tab[i]);
if (i != 0)
printf("_");
}
printf("\n");
}
static void mpb_renorm(mpb_t *r)
{
while (r->len > 1 && r->tab[r->len - 1] == 0)
r->len--;
}
#ifdef USE_POW5_TABLE
static const uint32_t pow5_table[17] = {
0x00000005, 0x00000019, 0x0000007d, 0x00000271,
0x00000c35, 0x00003d09, 0x0001312d, 0x0005f5e1,
0x001dcd65, 0x009502f9, 0x02e90edd, 0x0e8d4a51,
0x48c27395, 0x6bcc41e9, 0x1afd498d, 0x86f26fc1,
0xa2bc2ec5,
};
static const uint8_t pow5h_table[4] = {
0x00000001, 0x00000007, 0x00000023, 0x000000b1,
};
static const uint32_t pow5_inv_table[13] = {
0x99999999, 0x47ae147a, 0x0624dd2f, 0xa36e2eb1,
0x4f8b588e, 0x0c6f7a0b, 0xad7f29ab, 0x5798ee23,
0x12e0be82, 0xb7cdfd9d, 0x5fd7fe17, 0x19799812,
0xc25c2684,
};
#endif
/* return a^b */
static uint64_t pow_ui(uint32_t a, uint32_t b)
{
int i, n_bits;
uint64_t r;
if (b == 0)
return 1;
if (b == 1)
return a;
#ifdef USE_POW5_TABLE
if ((a == 5 || a == 10) && b <= 17) {
r = pow5_table[b - 1];
if (b >= 14) {
r |= (uint64_t)pow5h_table[b - 14] << 32;
}
if (a == 10)
r <<= b;
return r;
}
#endif
r = a;
n_bits = 32 - clz32(b);
for(i = n_bits - 2; i >= 0; i--) {
r *= r;
if ((b >> i) & 1)
r *= a;
}
return r;
}
static uint32_t pow_ui_inv(uint32_t *pr_inv, int *pshift, uint32_t a, uint32_t b)
{
uint32_t r_inv, r;
int shift;
#ifdef USE_POW5_TABLE
if (a == 5 && b >= 1 && b <= 13) {
r = pow5_table[b - 1];
shift = clz32(r);
r <<= shift;
r_inv = pow5_inv_table[b - 1];
} else
#endif
{
r = pow_ui(a, b);
shift = clz32(r);
r <<= shift;
r_inv = udiv1norm_init(r);
}
*pshift = shift;
*pr_inv = r_inv;
return r;
}
enum {
JS_RNDN, /* round to nearest, ties to even */
JS_RNDNA, /* round to nearest, ties away from zero */
JS_RNDZ,
};
static int mpb_get_bit(const mpb_t *r, int k)
{
int l;
l = (unsigned)k / LIMB_BITS;
k = k & (LIMB_BITS - 1);
if (l >= r->len)
return 0;
else
return (r->tab[l] >> k) & 1;
}
/* compute round(r / 2^shift). 'shift' can be negative */
static void mpb_shr_round(mpb_t *r, int shift, int rnd_mode)
{
int l, i;
if (shift == 0)
return;
if (shift < 0) {
shift = -shift;
l = (unsigned)shift / LIMB_BITS;
shift = shift & (LIMB_BITS - 1);
if (shift != 0) {
r->tab[r->len] = mp_shl(r->tab, r->tab, r->len, shift, 0);
r->len++;
mpb_renorm(r);
}
if (l > 0) {
for(i = r->len - 1; i >= 0; i--)
r->tab[i + l] = r->tab[i];
for(i = 0; i < l; i++)
r->tab[i] = 0;
r->len += l;
}
} else {
limb_t bit1, bit2;
int k, add_one;
switch(rnd_mode) {
default:
case JS_RNDZ:
add_one = 0;
break;
case JS_RNDN:
case JS_RNDNA:
bit1 = mpb_get_bit(r, shift - 1);
if (bit1) {
if (rnd_mode == JS_RNDNA) {
bit2 = 1;
} else {
/* bit2 = oring of all the bits after bit1 */
bit2 = 0;
if (shift >= 2) {
k = shift - 1;
l = (unsigned)k / LIMB_BITS;
k = k & (LIMB_BITS - 1);
for(i = 0; i < min_int(l, r->len); i++)
bit2 |= r->tab[i];
if (l < r->len)
bit2 |= r->tab[l] & (((limb_t)1 << k) - 1);
}
}
if (bit2) {
add_one = 1;
} else {
/* round to even */
add_one = mpb_get_bit(r, shift);
}
} else {
add_one = 0;
}
break;
}
l = (unsigned)shift / LIMB_BITS;
shift = shift & (LIMB_BITS - 1);
if (l >= r->len) {
r->len = 1;
r->tab[0] = add_one;
} else {
if (l > 0) {
r->len -= l;
for(i = 0; i < r->len; i++)
r->tab[i] = r->tab[i + l];
}
if (shift != 0) {
mp_shr(r->tab, r->tab, r->len, shift, 0);
mpb_renorm(r);
}
if (add_one) {
limb_t a;
a = mp_add_ui(r->tab, 1, r->len);
if (a)
r->tab[r->len++] = a;
}
}
}
}
/* return -1, 0 or 1 */
static int mpb_cmp(const mpb_t *a, const mpb_t *b)
{
mp_size_t i;
if (a->len < b->len)
return -1;
else if (a->len > b->len)
return 1;
for(i = a->len - 1; i >= 0; i--) {
if (a->tab[i] != b->tab[i]) {
if (a->tab[i] < b->tab[i])
return -1;
else
return 1;
}
}
return 0;
}
static void mpb_set_u64(mpb_t *r, uint64_t m)
{
#if LIMB_BITS == 64
r->tab[0] = m;
r->len = 1;
#else
r->tab[0] = m;
r->tab[1] = m >> LIMB_BITS;
if (r->tab[1] == 0)
r->len = 1;
else
r->len = 2;
#endif
}
static uint64_t mpb_get_u64(mpb_t *r)
{
#if LIMB_BITS == 64
return r->tab[0];
#else
if (r->len == 1) {
return r->tab[0];
} else {
return r->tab[0] | ((uint64_t)r->tab[1] << LIMB_BITS);
}
#endif
}
/* floor_log2() = position of the first non zero bit or -1 if zero. */
static int mpb_floor_log2(mpb_t *a)
{
limb_t v;
v = a->tab[a->len - 1];
if (v == 0)
return -1;
else
return a->len * LIMB_BITS - 1 - clz32(v);
}
#define MUL_LOG2_RADIX_BASE_LOG2 24
/* round((1 << MUL_LOG2_RADIX_BASE_LOG2)/log2(i + 2)) */
static const uint32_t mul_log2_radix_table[JS_RADIX_MAX - 1] = {
0x000000, 0xa1849d, 0x000000, 0x6e40d2,
0x6308c9, 0x5b3065, 0x000000, 0x50c24e,
0x4d104d, 0x4a0027, 0x4768ce, 0x452e54,
0x433d00, 0x418677, 0x000000, 0x3ea16b,
0x3d645a, 0x3c43c2, 0x3b3b9a, 0x3a4899,
0x39680b, 0x3897b3, 0x37d5af, 0x372069,
0x367686, 0x35d6df, 0x354072, 0x34b261,
0x342bea, 0x33ac62, 0x000000, 0x32bfd9,
0x3251dd, 0x31e8d6, 0x318465,
};
/* return floor(a / log2(radix)) for -2048 <= a <= 2047 */
static int mul_log2_radix(int a, int radix)
{
int radix_bits, mult;
if ((radix & (radix - 1)) == 0) {
/* if the radix is a power of two better to do it exactly */
radix_bits = 31 - clz32(radix);
if (a < 0)
a -= radix_bits - 1;
return a / radix_bits;
} else {
mult = mul_log2_radix_table[radix - 2];
return ((int64_t)a * mult) >> MUL_LOG2_RADIX_BASE_LOG2;
}
}
#if 0
static void build_mul_log2_radix_table(void)
{
int base, radix, mult, col, base_log2;
base_log2 = 24;
base = 1 << base_log2;
col = 0;
for(radix = 2; radix <= 36; radix++) {
if ((radix & (radix - 1)) == 0)
mult = 0;
else
mult = lrint((double)base / log2(radix));
printf("0x%06x, ", mult);
if (++col == 4) {
printf("\n");
col = 0;
}
}
printf("\n");
}
static void mul_log2_radix_test(void)
{
int radix, i, ref, r;
for(radix = 2; radix <= 36; radix++) {
for(i = -2048; i <= 2047; i++) {
ref = (int)floor((double)i / log2(radix));
r = mul_log2_radix(i, radix);
if (ref != r) {
printf("ERROR: radix=%d i=%d r=%d ref=%d\n",
radix, i, r, ref);
exit(1);
}
}
}
if (0)
build_mul_log2_radix_table();
}
#endif
static void u32toa_len(char *buf, uint32_t n, size_t len)
{
int digit, i;
for(i = len - 1; i >= 0; i--) {
digit = n % 10;
n = n / 10;
buf[i] = digit + '0';
}
}
/* for power of 2 radixes. len >= 1 */
static void u64toa_bin_len(char *buf, uint64_t n, unsigned int radix_bits, int len)
{
int digit, i;
unsigned int mask;
mask = (1 << radix_bits) - 1;
for(i = len - 1; i >= 0; i--) {
digit = n & mask;
n >>= radix_bits;
if (digit < 10)
digit += '0';
else
digit += 'a' - 10;
buf[i] = digit;
}
}
/* len >= 1. 2 <= radix <= 36 */
static void limb_to_a(char *buf, limb_t n, unsigned int radix, int len)
{
int digit, i;
if (radix == 10) {
/* specific case with constant divisor */
#if LIMB_BITS == 32
u32toa_len(buf, n, len);
#else
/* XXX: optimize */
for(i = len - 1; i >= 0; i--) {
digit = (limb_t)n % 10;
n = (limb_t)n / 10;
buf[i] = digit + '0';
}
#endif
} else {
for(i = len - 1; i >= 0; i--) {
digit = (limb_t)n % radix;
n = (limb_t)n / radix;
if (digit < 10)
digit += '0';
else
digit += 'a' - 10;
buf[i] = digit;
}
}
}
size_t u32toa(char *buf, uint32_t n)
{
char buf1[10], *q;
size_t len;
q = buf1 + sizeof(buf1);
do {
*--q = n % 10 + '0';
n /= 10;
} while (n != 0);
len = buf1 + sizeof(buf1) - q;
memcpy(buf, q, len);
return len;
}
size_t i32toa(char *buf, int32_t n)
{
if (n >= 0) {
return u32toa(buf, n);
} else {
buf[0] = '-';
return u32toa(buf + 1, -(uint32_t)n) + 1;
}
}
#ifdef USE_FAST_INT
size_t u64toa(char *buf, uint64_t n)
{
if (n < 0x100000000) {
return u32toa(buf, n);
} else {
uint64_t n1;
char *q = buf;
uint32_t n2;
n1 = n / 1000000000;
n %= 1000000000;
if (n1 >= 0x100000000) {
n2 = n1 / 1000000000;
n1 = n1 % 1000000000;
/* at most two digits */
if (n2 >= 10) {
*q++ = n2 / 10 + '0';
n2 %= 10;
}
*q++ = n2 + '0';
u32toa_len(q, n1, 9);
q += 9;
} else {
q += u32toa(q, n1);
}
u32toa_len(q, n, 9);
q += 9;
return q - buf;
}
}
size_t i64toa(char *buf, int64_t n)
{
if (n >= 0) {
return u64toa(buf, n);
} else {
buf[0] = '-';
return u64toa(buf + 1, -(uint64_t)n) + 1;
}
}
/* XXX: only tested for 1 <= n < 2^53 */
size_t u64toa_radix(char *buf, uint64_t n, unsigned int radix)
{
int radix_bits, l;
if (likely(radix == 10))
return u64toa(buf, n);
if ((radix & (radix - 1)) == 0) {
radix_bits = 31 - clz32(radix);
if (n == 0)
l = 1;
else
l = (64 - clz64(n) + radix_bits - 1) / radix_bits;
u64toa_bin_len(buf, n, radix_bits, l);
return l;
} else {
char buf1[41], *q; /* maximum length for radix = 3 */
size_t len;
int digit;
q = buf1 + sizeof(buf1);
do {
digit = n % radix;
n /= radix;
if (digit < 10)
digit += '0';
else
digit += 'a' - 10;
*--q = digit;
} while (n != 0);
len = buf1 + sizeof(buf1) - q;
memcpy(buf, q, len);
return len;
}
}
size_t i64toa_radix(char *buf, int64_t n, unsigned int radix)
{
if (n >= 0) {
return u64toa_radix(buf, n, radix);
} else {
buf[0] = '-';
return u64toa_radix(buf + 1, -(uint64_t)n, radix) + 1;
}
}
#endif /* USE_FAST_INT */
static const uint8_t digits_per_limb_table[JS_RADIX_MAX - 1] = {
#if LIMB_BITS == 32
32,20,16,13,12,11,10,10, 9, 9, 8, 8, 8, 8, 8, 7, 7, 7, 7, 7, 7, 7, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
#else
64,40,32,27,24,22,21,20,19,18,17,17,16,16,16,15,15,15,14,14,14,14,13,13,13,13,13,13,13,12,12,12,12,12,12,
#endif
};
static const uint32_t radix_base_table[JS_RADIX_MAX - 1] = {
0x00000000, 0xcfd41b91, 0x00000000, 0x48c27395,
0x81bf1000, 0x75db9c97, 0x40000000, 0xcfd41b91,
0x3b9aca00, 0x8c8b6d2b, 0x19a10000, 0x309f1021,
0x57f6c100, 0x98c29b81, 0x00000000, 0x18754571,
0x247dbc80, 0x3547667b, 0x4c4b4000, 0x6b5a6e1d,
0x94ace180, 0xcaf18367, 0x0b640000, 0x0e8d4a51,
0x1269ae40, 0x17179149, 0x1cb91000, 0x23744899,
0x2b73a840, 0x34e63b41, 0x40000000, 0x4cfa3cc1,
0x5c13d840, 0x6d91b519, 0x81bf1000,
};
/* XXX: remove the table ? */
static uint8_t dtoa_max_digits_table[JS_RADIX_MAX - 1] = {
54, 35, 28, 24, 22, 20, 19, 18, 17, 17, 16, 16, 15, 15, 15, 14, 14, 14, 14, 14, 13, 13, 13, 13, 13, 13, 13, 12, 12, 12, 12, 12, 12, 12, 12,
};
/* we limit the maximum number of significant digits for atod to about
128 bits of precision for non power of two bases. The only
requirement for Javascript is at least 20 digits in base 10. For
power of two bases, we do an exact rounding in all the cases. */
static uint8_t atod_max_digits_table[JS_RADIX_MAX - 1] = {
64, 80, 32, 55, 49, 45, 21, 40, 38, 37, 35, 34, 33, 32, 16, 31, 30, 30, 29, 29, 28, 28, 27, 27, 27, 26, 26, 26, 26, 25, 12, 25, 25, 24, 24,
};
/* if abs(d) >= B^max_exponent, it is an overflow */
static const int16_t max_exponent[JS_RADIX_MAX - 1] = {
1024, 647, 512, 442, 397, 365, 342, 324,
309, 297, 286, 277, 269, 263, 256, 251,
246, 242, 237, 234, 230, 227, 224, 221,
218, 216, 214, 211, 209, 207, 205, 203,
202, 200, 199,
};
/* if abs(d) <= B^min_exponent, it is an underflow */
static const int16_t min_exponent[JS_RADIX_MAX - 1] = {
-1075, -679, -538, -463, -416, -383, -359, -340,
-324, -311, -300, -291, -283, -276, -269, -263,
-258, -254, -249, -245, -242, -238, -235, -232,
-229, -227, -224, -222, -220, -217, -215, -214,
-212, -210, -208,
};
#if 0
void build_tables(void)
{
int r, j, radix, n, col, i;
/* radix_base_table */
for(radix = 2; radix <= 36; radix++) {
r = 1;
for(j = 0; j < digits_per_limb_table[radix - 2]; j++) {
r *= radix;
}
printf(" 0x%08x,", r);
if ((radix % 4) == 1)
printf("\n");
}
printf("\n");
/* dtoa_max_digits_table */
for(radix = 2; radix <= 36; radix++) {
/* Note: over estimated when the radix is a power of two */
printf(" %d,", 1 + (int)ceil(53.0 / log2(radix)));
}
printf("\n");
/* atod_max_digits_table */
for(radix = 2; radix <= 36; radix++) {
if ((radix & (radix - 1)) == 0) {
/* 64 bits is more than enough */
n = (int)floor(64.0 / log2(radix));
} else {
n = (int)floor(128.0 / log2(radix));
}
printf(" %d,", n);
}
printf("\n");
printf("static const int16_t max_exponent[JS_RADIX_MAX - 1] = {\n");
col = 0;
for(radix = 2; radix <= 36; radix++) {
printf("%5d, ", (int)ceil(1024 / log2(radix)));
if (++col == 8) {
col = 0;
printf("\n");
}
}
printf("\n};\n\n");
printf("static const int16_t min_exponent[JS_RADIX_MAX - 1] = {\n");
col = 0;
for(radix = 2; radix <= 36; radix++) {
printf("%5d, ", (int)floor(-1075 / log2(radix)));
if (++col == 8) {
col = 0;
printf("\n");
}
}
printf("\n};\n\n");
printf("static const uint32_t pow5_table[16] = {\n");
col = 0;
for(i = 2; i <= 17; i++) {
r = 1;
for(j = 0; j < i; j++) {
r *= 5;
}
printf("0x%08x, ", r);
if (++col == 4) {
col = 0;
printf("\n");
}
}
printf("\n};\n\n");
/* high part */
printf("static const uint8_t pow5h_table[4] = {\n");
col = 0;
for(i = 14; i <= 17; i++) {
uint64_t r1;
r1 = 1;
for(j = 0; j < i; j++) {
r1 *= 5;
}
printf("0x%08x, ", (uint32_t)(r1 >> 32));
if (++col == 4) {
col = 0;
printf("\n");
}
}
printf("\n};\n\n");
}
#endif
/* n_digits >= 1. 0 <= dot_pos <= n_digits. If dot_pos == n_digits,
the dot is not displayed. 'a' is modified. */
static int output_digits(char *buf,
mpb_t *a, int radix, int n_digits1,
int dot_pos)
{
int n_digits, digits_per_limb, radix_bits, n, len;
n_digits = n_digits1;
if ((radix & (radix - 1)) == 0) {
/* radix = 2^radix_bits */
radix_bits = 31 - clz32(radix);
} else {
radix_bits = 0;
}
digits_per_limb = digits_per_limb_table[radix - 2];
if (radix_bits != 0) {
for(;;) {
n = min_int(n_digits, digits_per_limb);
n_digits -= n;
u64toa_bin_len(buf + n_digits, a->tab[0], radix_bits, n);
if (n_digits == 0)
break;
mpb_shr_round(a, digits_per_limb * radix_bits, JS_RNDZ);
}
} else {
limb_t r;
while (n_digits != 0) {
n = min_int(n_digits, digits_per_limb);
n_digits -= n;
r = mp_div1(a->tab, a->tab, a->len, radix_base_table[radix - 2], 0);
mpb_renorm(a);
limb_to_a(buf + n_digits, r, radix, n);
}
}
/* add the dot */
len = n_digits1;
if (dot_pos != n_digits1) {
memmove(buf + dot_pos + 1, buf + dot_pos, n_digits1 - dot_pos);
buf[dot_pos] = '.';
len++;
}
return len;
}
/* return (a, e_offset) such that a = a * (radix1*2^radix_shift)^f *
2^-e_offset. 'f' can be negative. */
static int mul_pow(mpb_t *a, int radix1, int radix_shift, int f, BOOL is_int, int e)
{
int e_offset, d, n, n0;
e_offset = -f * radix_shift;
if (radix1 != 1) {
d = digits_per_limb_table[radix1 - 2];
if (f >= 0) {
limb_t h, b;
b = 0;
n0 = 0;
while (f != 0) {
n = min_int(f, d);
if (n != n0) {
b = pow_ui(radix1, n);
n0 = n;
}
h = mp_mul1(a->tab, a->tab, a->len, b, 0);
if (h != 0) {
a->tab[a->len++] = h;
}
f -= n;
}
} else {
int extra_bits, l, shift;
limb_t r, rem, b, b_inv;
f = -f;
l = (f + d - 1) / d; /* high bound for the number of limbs (XXX: make it better) */
e_offset += l * LIMB_BITS;
if (!is_int) {
/* at least 'e' bits are needed in the final result for rounding */
extra_bits = max_int(e - mpb_floor_log2(a), 0);
} else {
/* at least two extra bits are needed in the final result
for rounding */
extra_bits = max_int(2 + e - e_offset, 0);
}
e_offset += extra_bits;
mpb_shr_round(a, -(l * LIMB_BITS + extra_bits), JS_RNDZ);
b = 0;
b_inv = 0;
shift = 0;
n0 = 0;
rem = 0;
while (f != 0) {
n = min_int(f, d);
if (n != n0) {
b = pow_ui_inv(&b_inv, &shift, radix1, n);
n0 = n;
}
r = mp_div1norm(a->tab, a->tab, a->len, b, 0, b_inv, shift);
rem |= r;
mpb_renorm(a);
f -= n;
}
/* if the remainder is non zero, use it for rounding */
a->tab[0] |= (rem != 0);
}
}
return e_offset;
}
/* tmp1 = round(m*2^e*radix^f). 'tmp0' is a temporary storage */
static void mul_pow_round(mpb_t *tmp1, uint64_t m, int e, int radix1, int radix_shift, int f,
int rnd_mode)
{
int e_offset;
mpb_set_u64(tmp1, m);
e_offset = mul_pow(tmp1, radix1, radix_shift, f, TRUE, e);
mpb_shr_round(tmp1, -e + e_offset, rnd_mode);
}
/* return round(a*2^e_offset) rounded as a float64. 'a' is modified */
static uint64_t round_to_d(int *pe, mpb_t *a, int e_offset, int rnd_mode)
{
int e;
uint64_t m;
if (a->tab[0] == 0 && a->len == 1) {
/* zero result */
m = 0;
e = 0; /* don't care */
} else {
int prec, prec1, e_min;
e = mpb_floor_log2(a) + 1 - e_offset;
prec1 = 53;
e_min = -1021;
if (e < e_min) {
/* subnormal result or zero */
prec = prec1 - (e_min - e);
} else {
prec = prec1;
}
mpb_shr_round(a, e + e_offset - prec, rnd_mode);
m = mpb_get_u64(a);
m <<= (53 - prec);
/* mantissa overflow due to rounding */
if (m >= (uint64_t)1 << 53) {
m >>= 1;
e++;
}
}
*pe = e;
return m;