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author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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1 /* Decimal 64-bit format module for the decNumber C Library.
2 Copyright (C) 2005, 2007, 2009 Free Software Foundation, Inc.
3 Contributed by IBM Corporation. Author Mike Cowlishaw.
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
11
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
16
17 Under Section 7 of GPL version 3, you are granted additional
18 permissions described in the GCC Runtime Library Exception, version
19 3.1, as published by the Free Software Foundation.
20
21 You should have received a copy of the GNU General Public License and
22 a copy of the GCC Runtime Library Exception along with this program;
23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 <http://www.gnu.org/licenses/>. */
25
26 /* ------------------------------------------------------------------ */
27 /* Decimal 64-bit format module */
28 /* ------------------------------------------------------------------ */
29 /* This module comprises the routines for decimal64 format numbers. */
30 /* Conversions are supplied to and from decNumber and String. */
31 /* */
32 /* This is used when decNumber provides operations, either for all */
33 /* operations or as a proxy between decNumber and decSingle. */
34 /* */
35 /* Error handling is the same as decNumber (qv.). */
36 /* ------------------------------------------------------------------ */
37 #include <string.h> /* [for memset/memcpy] */
38 #include <stdio.h> /* [for printf] */
39
40 #include "dconfig.h" /* GCC definitions */
41 #define DECNUMDIGITS 16 /* make decNumbers with space for 16 */
42 #include "decNumber.h" /* base number library */
43 #include "decNumberLocal.h" /* decNumber local types, etc. */
44 #include "decimal64.h" /* our primary include */
45
46 /* Utility routines and tables [in decimal64.c]; externs for C++ */
47 extern const uInt COMBEXP[32], COMBMSD[32];
48 extern const uShort DPD2BIN[1024];
49 extern const uShort BIN2DPD[1000];
50 extern const uByte BIN2CHAR[4001];
51
52 extern void decDigitsFromDPD(decNumber *, const uInt *, Int);
53 extern void decDigitsToDPD(const decNumber *, uInt *, Int);
54
55 #if DECTRACE || DECCHECK
56 void decimal64Show(const decimal64 *); /* for debug */
57 extern void decNumberShow(const decNumber *); /* .. */
58 #endif
59
60 /* Useful macro */
61 /* Clear a structure (e.g., a decNumber) */
62 #define DEC_clear(d) memset(d, 0, sizeof(*d))
63
64 /* define and include the tables to use for conversions */
65 #define DEC_BIN2CHAR 1
66 #define DEC_DPD2BIN 1
67 #define DEC_BIN2DPD 1 /* used for all sizes */
68 #include "decDPD.h" /* lookup tables */
69
70 /* ------------------------------------------------------------------ */
71 /* decimal64FromNumber -- convert decNumber to decimal64 */
72 /* */
73 /* ds is the target decimal64 */
74 /* dn is the source number (assumed valid) */
75 /* set is the context, used only for reporting errors */
76 /* */
77 /* The set argument is used only for status reporting and for the */
78 /* rounding mode (used if the coefficient is more than DECIMAL64_Pmax */
79 /* digits or an overflow is detected). If the exponent is out of the */
80 /* valid range then Overflow or Underflow will be raised. */
81 /* After Underflow a subnormal result is possible. */
82 /* */
83 /* DEC_Clamped is set if the number has to be 'folded down' to fit, */
84 /* by reducing its exponent and multiplying the coefficient by a */
85 /* power of ten, or if the exponent on a zero had to be clamped. */
86 /* ------------------------------------------------------------------ */
87 decimal64 * decimal64FromNumber(decimal64 *d64, const decNumber *dn,
88 decContext *set) {
89 uInt status=0; /* status accumulator */
90 Int ae; /* adjusted exponent */
91 decNumber dw; /* work */
92 decContext dc; /* .. */
93 uInt *pu; /* .. */
94 uInt comb, exp; /* .. */
95 uInt targar[2]={0, 0}; /* target 64-bit */
96 #define targhi targar[1] /* name the word with the sign */
97 #define targlo targar[0] /* and the other */
98
99 /* If the number has too many digits, or the exponent could be */
100 /* out of range then reduce the number under the appropriate */
101 /* constraints. This could push the number to Infinity or zero, */
102 /* so this check and rounding must be done before generating the */
103 /* decimal64] */
104 ae=dn->exponent+dn->digits-1; /* [0 if special] */
105 if (dn->digits>DECIMAL64_Pmax /* too many digits */
106 || ae>DECIMAL64_Emax /* likely overflow */
107 || ae<DECIMAL64_Emin) { /* likely underflow */
108 decContextDefault(&dc, DEC_INIT_DECIMAL64); /* [no traps] */
109 dc.round=set->round; /* use supplied rounding */
110 decNumberPlus(&dw, dn, &dc); /* (round and check) */
111 /* [this changes -0 to 0, so enforce the sign...] */
112 dw.bits|=dn->bits&DECNEG;
113 status=dc.status; /* save status */
114 dn=&dw; /* use the work number */
115 } /* maybe out of range */
116
117 if (dn->bits&DECSPECIAL) { /* a special value */
118 if (dn->bits&DECINF) targhi=DECIMAL_Inf<<24;
119 else { /* sNaN or qNaN */
120 if ((*dn->lsu!=0 || dn->digits>1) /* non-zero coefficient */
121 && (dn->digits<DECIMAL64_Pmax)) { /* coefficient fits */
122 decDigitsToDPD(dn, targar, 0);
123 }
124 if (dn->bits&DECNAN) targhi|=DECIMAL_NaN<<24;
125 else targhi|=DECIMAL_sNaN<<24;
126 } /* a NaN */
127 } /* special */
128
129 else { /* is finite */
130 if (decNumberIsZero(dn)) { /* is a zero */
131 /* set and clamp exponent */
132 if (dn->exponent<-DECIMAL64_Bias) {
133 exp=0; /* low clamp */
134 status|=DEC_Clamped;
135 }
136 else {
137 exp=dn->exponent+DECIMAL64_Bias; /* bias exponent */
138 if (exp>DECIMAL64_Ehigh) { /* top clamp */
139 exp=DECIMAL64_Ehigh;
140 status|=DEC_Clamped;
141 }
142 }
143 comb=(exp>>5) & 0x18; /* msd=0, exp top 2 bits .. */
144 }
145 else { /* non-zero finite number */
146 uInt msd; /* work */
147 Int pad=0; /* coefficient pad digits */
148
149 /* the dn is known to fit, but it may need to be padded */
150 exp=(uInt)(dn->exponent+DECIMAL64_Bias); /* bias exponent */
151 if (exp>DECIMAL64_Ehigh) { /* fold-down case */
152 pad=exp-DECIMAL64_Ehigh;
153 exp=DECIMAL64_Ehigh; /* [to maximum] */
154 status|=DEC_Clamped;
155 }
156
157 /* fastpath common case */
158 if (DECDPUN==3 && pad==0) {
159 uInt dpd[6]={0,0,0,0,0,0};
160 uInt i;
161 Int d=dn->digits;
162 for (i=0; d>0; i++, d-=3) dpd[i]=BIN2DPD[dn->lsu[i]];
163 targlo =dpd[0];
164 targlo|=dpd[1]<<10;
165 targlo|=dpd[2]<<20;
166 if (dn->digits>6) {
167 targlo|=dpd[3]<<30;
168 targhi =dpd[3]>>2;
169 targhi|=dpd[4]<<8;
170 }
171 msd=dpd[5]; /* [did not really need conversion] */
172 }
173 else { /* general case */
174 decDigitsToDPD(dn, targar, pad);
175 /* save and clear the top digit */
176 msd=targhi>>18;
177 targhi&=0x0003ffff;
178 }
179
180 /* create the combination field */
181 if (msd>=8) comb=0x18 | ((exp>>7) & 0x06) | (msd & 0x01);
182 else comb=((exp>>5) & 0x18) | msd;
183 }
184 targhi|=comb<<26; /* add combination field .. */
185 targhi|=(exp&0xff)<<18; /* .. and exponent continuation */
186 } /* finite */
187
188 if (dn->bits&DECNEG) targhi|=0x80000000; /* add sign bit */
189
190 /* now write to storage; this is now always endian */
191 pu=(uInt *)d64->bytes; /* overlay */
192 if (DECLITEND) {
193 pu[0]=targar[0]; /* directly store the low int */
194 pu[1]=targar[1]; /* then the high int */
195 }
196 else {
197 pu[0]=targar[1]; /* directly store the high int */
198 pu[1]=targar[0]; /* then the low int */
199 }
200
201 if (status!=0) decContextSetStatus(set, status); /* pass on status */
202 /* decimal64Show(d64); */
203 return d64;
204 } /* decimal64FromNumber */
205
206 /* ------------------------------------------------------------------ */
207 /* decimal64ToNumber -- convert decimal64 to decNumber */
208 /* d64 is the source decimal64 */
209 /* dn is the target number, with appropriate space */
210 /* No error is possible. */
211 /* ------------------------------------------------------------------ */
212 decNumber * decimal64ToNumber(const decimal64 *d64, decNumber *dn) {
213 uInt msd; /* coefficient MSD */
214 uInt exp; /* exponent top two bits */
215 uInt comb; /* combination field */
216 const uInt *pu; /* work */
217 Int need; /* .. */
218 uInt sourar[2]; /* source 64-bit */
219 #define sourhi sourar[1] /* name the word with the sign */
220 #define sourlo sourar[0] /* and the lower word */
221
222 /* load source from storage; this is endian */
223 pu=(const uInt *)d64->bytes; /* overlay */
224 if (DECLITEND) {
225 sourlo=pu[0]; /* directly load the low int */
226 sourhi=pu[1]; /* then the high int */
227 }
228 else {
229 sourhi=pu[0]; /* directly load the high int */
230 sourlo=pu[1]; /* then the low int */
231 }
232
233 comb=(sourhi>>26)&0x1f; /* combination field */
234
235 decNumberZero(dn); /* clean number */
236 if (sourhi&0x80000000) dn->bits=DECNEG; /* set sign if negative */
237
238 msd=COMBMSD[comb]; /* decode the combination field */
239 exp=COMBEXP[comb]; /* .. */
240
241 if (exp==3) { /* is a special */
242 if (msd==0) {
243 dn->bits|=DECINF;
244 return dn; /* no coefficient needed */
245 }
246 else if (sourhi&0x02000000) dn->bits|=DECSNAN;
247 else dn->bits|=DECNAN;
248 msd=0; /* no top digit */
249 }
250 else { /* is a finite number */
251 dn->exponent=(exp<<8)+((sourhi>>18)&0xff)-DECIMAL64_Bias; /* unbiased */
252 }
253
254 /* get the coefficient */
255 sourhi&=0x0003ffff; /* clean coefficient continuation */
256 if (msd) { /* non-zero msd */
257 sourhi|=msd<<18; /* prefix to coefficient */
258 need=6; /* process 6 declets */
259 }
260 else { /* msd=0 */
261 if (!sourhi) { /* top word 0 */
262 if (!sourlo) return dn; /* easy: coefficient is 0 */
263 need=3; /* process at least 3 declets */
264 if (sourlo&0xc0000000) need++; /* process 4 declets */
265 /* [could reduce some more, here] */
266 }
267 else { /* some bits in top word, msd=0 */
268 need=4; /* process at least 4 declets */
269 if (sourhi&0x0003ff00) need++; /* top declet!=0, process 5 */
270 }
271 } /*msd=0 */
272
273 decDigitsFromDPD(dn, sourar, need); /* process declets */
274 return dn;
275 } /* decimal64ToNumber */
276
277
278 /* ------------------------------------------------------------------ */
279 /* to-scientific-string -- conversion to numeric string */
280 /* to-engineering-string -- conversion to numeric string */
281 /* */
282 /* decimal64ToString(d64, string); */
283 /* decimal64ToEngString(d64, string); */
284 /* */
285 /* d64 is the decimal64 format number to convert */
286 /* string is the string where the result will be laid out */
287 /* */
288 /* string must be at least 24 characters */
289 /* */
290 /* No error is possible, and no status can be set. */
291 /* ------------------------------------------------------------------ */
292 char * decimal64ToEngString(const decimal64 *d64, char *string){
293 decNumber dn; /* work */
294 decimal64ToNumber(d64, &dn);
295 decNumberToEngString(&dn, string);
296 return string;
297 } /* decimal64ToEngString */
298
299 char * decimal64ToString(const decimal64 *d64, char *string){
300 uInt msd; /* coefficient MSD */
301 Int exp; /* exponent top two bits or full */
302 uInt comb; /* combination field */
303 char *cstart; /* coefficient start */
304 char *c; /* output pointer in string */
305 const uInt *pu; /* work */
306 char *s, *t; /* .. (source, target) */
307 Int dpd; /* .. */
308 Int pre, e; /* .. */
309 const uByte *u; /* .. */
310
311 uInt sourar[2]; /* source 64-bit */
312 #define sourhi sourar[1] /* name the word with the sign */
313 #define sourlo sourar[0] /* and the lower word */
314
315 /* load source from storage; this is endian */
316 pu=(const uInt *)d64->bytes; /* overlay */
317 if (DECLITEND) {
318 sourlo=pu[0]; /* directly load the low int */
319 sourhi=pu[1]; /* then the high int */
320 }
321 else {
322 sourhi=pu[0]; /* directly load the high int */
323 sourlo=pu[1]; /* then the low int */
324 }
325
326 c=string; /* where result will go */
327 if (((Int)sourhi)<0) *c++='-'; /* handle sign */
328
329 comb=(sourhi>>26)&0x1f; /* combination field */
330 msd=COMBMSD[comb]; /* decode the combination field */
331 exp=COMBEXP[comb]; /* .. */
332
333 if (exp==3) {
334 if (msd==0) { /* infinity */
335 strcpy(c, "Inf");
336 strcpy(c+3, "inity");
337 return string; /* easy */
338 }
339 if (sourhi&0x02000000) *c++='s'; /* sNaN */
340 strcpy(c, "NaN"); /* complete word */
341 c+=3; /* step past */
342 if (sourlo==0 && (sourhi&0x0003ffff)==0) return string; /* zero payload */
343 /* otherwise drop through to add integer; set correct exp */
344 exp=0; msd=0; /* setup for following code */
345 }
346 else exp=(exp<<8)+((sourhi>>18)&0xff)-DECIMAL64_Bias;
347
348 /* convert 16 digits of significand to characters */
349 cstart=c; /* save start of coefficient */
350 if (msd) *c++='0'+(char)msd; /* non-zero most significant digit */
351
352 /* Now decode the declets. After extracting each one, it is */
353 /* decoded to binary and then to a 4-char sequence by table lookup; */
354 /* the 4-chars are a 1-char length (significant digits, except 000 */
355 /* has length 0). This allows us to left-align the first declet */
356 /* with non-zero content, then remaining ones are full 3-char */
357 /* length. We use fixed-length memcpys because variable-length */
358 /* causes a subroutine call in GCC. (These are length 4 for speed */
359 /* and are safe because the array has an extra terminator byte.) */
360 #define dpd2char u=&BIN2CHAR[DPD2BIN[dpd]*4]; \
361 if (c!=cstart) {memcpy(c, u+1, 4); c+=3;} \
362 else if (*u) {memcpy(c, u+4-*u, 4); c+=*u;}
363
364 dpd=(sourhi>>8)&0x3ff; /* declet 1 */
365 dpd2char;
366 dpd=((sourhi&0xff)<<2) | (sourlo>>30); /* declet 2 */
367 dpd2char;
368 dpd=(sourlo>>20)&0x3ff; /* declet 3 */
369 dpd2char;
370 dpd=(sourlo>>10)&0x3ff; /* declet 4 */
371 dpd2char;
372 dpd=(sourlo)&0x3ff; /* declet 5 */
373 dpd2char;
374
375 if (c==cstart) *c++='0'; /* all zeros -- make 0 */
376
377 if (exp==0) { /* integer or NaN case -- easy */
378 *c='\0'; /* terminate */
379 return string;
380 }
381
382 /* non-0 exponent */
383 e=0; /* assume no E */
384 pre=c-cstart+exp;
385 /* [here, pre-exp is the digits count (==1 for zero)] */
386 if (exp>0 || pre<-5) { /* need exponential form */
387 e=pre-1; /* calculate E value */
388 pre=1; /* assume one digit before '.' */
389 } /* exponential form */
390
391 /* modify the coefficient, adding 0s, '.', and E+nn as needed */
392 s=c-1; /* source (LSD) */
393 if (pre>0) { /* ddd.ddd (plain), perhaps with E */
394 char *dotat=cstart+pre;
395 if (dotat<c) { /* if embedded dot needed... */
396 t=c; /* target */
397 for (; s>=dotat; s--, t--) *t=*s; /* open the gap; leave t at gap */
398 *t='.'; /* insert the dot */
399 c++; /* length increased by one */
400 }
401
402 /* finally add the E-part, if needed; it will never be 0, and has */
403 /* a maximum length of 3 digits */
404 if (e!=0) {
405 *c++='E'; /* starts with E */
406 *c++='+'; /* assume positive */
407 if (e<0) {
408 *(c-1)='-'; /* oops, need '-' */
409 e=-e; /* uInt, please */
410 }
411 u=&BIN2CHAR[e*4]; /* -> length byte */
412 memcpy(c, u+4-*u, 4); /* copy fixed 4 characters [is safe] */
413 c+=*u; /* bump pointer appropriately */
414 }
415 *c='\0'; /* add terminator */
416 /*printf("res %s\n", string); */
417 return string;
418 } /* pre>0 */
419
420 /* -5<=pre<=0: here for plain 0.ddd or 0.000ddd forms (can never have E) */
421 t=c+1-pre;
422 *(t+1)='\0'; /* can add terminator now */
423 for (; s>=cstart; s--, t--) *t=*s; /* shift whole coefficient right */
424 c=cstart;
425 *c++='0'; /* always starts with 0. */
426 *c++='.';
427 for (; pre<0; pre++) *c++='0'; /* add any 0's after '.' */
428 /*printf("res %s\n", string); */
429 return string;
430 } /* decimal64ToString */
431
432 /* ------------------------------------------------------------------ */
433 /* to-number -- conversion from numeric string */
434 /* */
435 /* decimal64FromString(result, string, set); */
436 /* */
437 /* result is the decimal64 format number which gets the result of */
438 /* the conversion */
439 /* *string is the character string which should contain a valid */
440 /* number (which may be a special value) */
441 /* set is the context */
442 /* */
443 /* The context is supplied to this routine is used for error handling */
444 /* (setting of status and traps) and for the rounding mode, only. */
445 /* If an error occurs, the result will be a valid decimal64 NaN. */
446 /* ------------------------------------------------------------------ */
447 decimal64 * decimal64FromString(decimal64 *result, const char *string,
448 decContext *set) {
449 decContext dc; /* work */
450 decNumber dn; /* .. */
451
452 decContextDefault(&dc, DEC_INIT_DECIMAL64); /* no traps, please */
453 dc.round=set->round; /* use supplied rounding */
454
455 decNumberFromString(&dn, string, &dc); /* will round if needed */
456
457 decimal64FromNumber(result, &dn, &dc);
458 if (dc.status!=0) { /* something happened */
459 decContextSetStatus(set, dc.status); /* .. pass it on */
460 }
461 return result;
462 } /* decimal64FromString */
463
464 /* ------------------------------------------------------------------ */
465 /* decimal64IsCanonical -- test whether encoding is canonical */
466 /* d64 is the source decimal64 */
467 /* returns 1 if the encoding of d64 is canonical, 0 otherwise */
468 /* No error is possible. */
469 /* ------------------------------------------------------------------ */
470 uint32_t decimal64IsCanonical(const decimal64 *d64) {
471 decNumber dn; /* work */
472 decimal64 canon; /* .. */
473 decContext dc; /* .. */
474 decContextDefault(&dc, DEC_INIT_DECIMAL64);
475 decimal64ToNumber(d64, &dn);
476 decimal64FromNumber(&canon, &dn, &dc);/* canon will now be canonical */
477 return memcmp(d64, &canon, DECIMAL64_Bytes)==0;
478 } /* decimal64IsCanonical */
479
480 /* ------------------------------------------------------------------ */
481 /* decimal64Canonical -- copy an encoding, ensuring it is canonical */
482 /* d64 is the source decimal64 */
483 /* result is the target (may be the same decimal64) */
484 /* returns result */
485 /* No error is possible. */
486 /* ------------------------------------------------------------------ */
487 decimal64 * decimal64Canonical(decimal64 *result, const decimal64 *d64) {
488 decNumber dn; /* work */
489 decContext dc; /* .. */
490 decContextDefault(&dc, DEC_INIT_DECIMAL64);
491 decimal64ToNumber(d64, &dn);
492 decimal64FromNumber(result, &dn, &dc);/* result will now be canonical */
493 return result;
494 } /* decimal64Canonical */
495
496 #if DECTRACE || DECCHECK
497 /* Macros for accessing decimal64 fields. These assume the
498 argument is a reference (pointer) to the decimal64 structure,
499 and the decimal64 is in network byte order (big-endian) */
500 /* Get sign */
501 #define decimal64Sign(d) ((unsigned)(d)->bytes[0]>>7)
502
503 /* Get combination field */
504 #define decimal64Comb(d) (((d)->bytes[0] & 0x7c)>>2)
505
506 /* Get exponent continuation [does not remove bias] */
507 #define decimal64ExpCon(d) ((((d)->bytes[0] & 0x03)<<6) \
508 | ((unsigned)(d)->bytes[1]>>2))
509
510 /* Set sign [this assumes sign previously 0] */
511 #define decimal64SetSign(d, b) { \
512 (d)->bytes[0]|=((unsigned)(b)<<7);}
513
514 /* Set exponent continuation [does not apply bias] */
515 /* This assumes range has been checked and exponent previously 0; */
516 /* type of exponent must be unsigned */
517 #define decimal64SetExpCon(d, e) { \
518 (d)->bytes[0]|=(uint8_t)((e)>>6); \
519 (d)->bytes[1]|=(uint8_t)(((e)&0x3F)<<2);}
520
521 /* ------------------------------------------------------------------ */
522 /* decimal64Show -- display a decimal64 in hexadecimal [debug aid] */
523 /* d64 -- the number to show */
524 /* ------------------------------------------------------------------ */
525 /* Also shows sign/cob/expconfields extracted */
526 void decimal64Show(const decimal64 *d64) {
527 char buf[DECIMAL64_Bytes*2+1];
528 Int i, j=0;
529
530 if (DECLITEND) {
531 for (i=0; i<DECIMAL64_Bytes; i++, j+=2) {
532 sprintf(&buf[j], "%02x", d64->bytes[7-i]);
533 }
534 printf(" D64> %s [S:%d Cb:%02x Ec:%02x] LittleEndian\n", buf,
535 d64->bytes[7]>>7, (d64->bytes[7]>>2)&0x1f,
536 ((d64->bytes[7]&0x3)<<6)| (d64->bytes[6]>>2));
537 }
538 else { /* big-endian */
539 for (i=0; i<DECIMAL64_Bytes; i++, j+=2) {
540 sprintf(&buf[j], "%02x", d64->bytes[i]);
541 }
542 printf(" D64> %s [S:%d Cb:%02x Ec:%02x] BigEndian\n", buf,
543 decimal64Sign(d64), decimal64Comb(d64), decimal64ExpCon(d64));
544 }
545 } /* decimal64Show */
546 #endif
547
548 /* ================================================================== */
549 /* Shared utility routines and tables */
550 /* ================================================================== */
551 /* define and include the conversion tables to use for shared code */
552 #if DECDPUN==3
553 #define DEC_DPD2BIN 1
554 #else
555 #define DEC_DPD2BCD 1
556 #endif
557 #include "decDPD.h" /* lookup tables */
558
559 /* The maximum number of decNumberUnits needed for a working copy of */
560 /* the units array is the ceiling of digits/DECDPUN, where digits is */
561 /* the maximum number of digits in any of the formats for which this */
562 /* is used. decimal128.h must not be included in this module, so, as */
563 /* a very special case, that number is defined as a literal here. */
564 #define DECMAX754 34
565 #define DECMAXUNITS ((DECMAX754+DECDPUN-1)/DECDPUN)
566
567 /* ------------------------------------------------------------------ */
568 /* Combination field lookup tables (uInts to save measurable work) */
569 /* */
570 /* COMBEXP - 2-bit most-significant-bits of exponent */
571 /* [11 if an Infinity or NaN] */
572 /* COMBMSD - 4-bit most-significant-digit */
573 /* [0=Infinity, 1=NaN if COMBEXP=11] */
574 /* */
575 /* Both are indexed by the 5-bit combination field (0-31) */
576 /* ------------------------------------------------------------------ */
577 const uInt COMBEXP[32]={0, 0, 0, 0, 0, 0, 0, 0,
578 1, 1, 1, 1, 1, 1, 1, 1,
579 2, 2, 2, 2, 2, 2, 2, 2,
580 0, 0, 1, 1, 2, 2, 3, 3};
581 const uInt COMBMSD[32]={0, 1, 2, 3, 4, 5, 6, 7,
582 0, 1, 2, 3, 4, 5, 6, 7,
583 0, 1, 2, 3, 4, 5, 6, 7,
584 8, 9, 8, 9, 8, 9, 0, 1};
585
586 /* ------------------------------------------------------------------ */
587 /* decDigitsToDPD -- pack coefficient into DPD form */
588 /* */
589 /* dn is the source number (assumed valid, max DECMAX754 digits) */
590 /* targ is 1, 2, or 4-element uInt array, which the caller must */
591 /* have cleared to zeros */
592 /* shift is the number of 0 digits to add on the right (normally 0) */
593 /* */
594 /* The coefficient must be known small enough to fit. The full */
595 /* coefficient is copied, including the leading 'odd' digit. This */
596 /* digit is retrieved and packed into the combination field by the */
597 /* caller. */
598 /* */
599 /* The target uInts are altered only as necessary to receive the */
600 /* digits of the decNumber. When more than one uInt is needed, they */
601 /* are filled from left to right (that is, the uInt at offset 0 will */
602 /* end up with the least-significant digits). */
603 /* */
604 /* shift is used for 'fold-down' padding. */
605 /* */
606 /* No error is possible. */
607 /* ------------------------------------------------------------------ */
608 #if DECDPUN<=4
609 /* Constant multipliers for divide-by-power-of five using reciprocal */
610 /* multiply, after removing powers of 2 by shifting, and final shift */
611 /* of 17 [we only need up to **4] */
612 static const uInt multies[]={131073, 26215, 5243, 1049, 210};
613 /* QUOT10 -- macro to return the quotient of unit u divided by 10**n */
614 #define QUOT10(u, n) ((((uInt)(u)>>(n))*multies[n])>>17)
615 #endif
616 void decDigitsToDPD(const decNumber *dn, uInt *targ, Int shift) {
617 Int cut; /* work */
618 Int n; /* output bunch counter */
619 Int digits=dn->digits; /* digit countdown */
620 uInt dpd; /* densely packed decimal value */
621 uInt bin; /* binary value 0-999 */
622 uInt *uout=targ; /* -> current output uInt */
623 uInt uoff=0; /* -> current output offset [from right] */
624 const Unit *inu=dn->lsu; /* -> current input unit */
625 Unit uar[DECMAXUNITS]; /* working copy of units, iff shifted */
626 #if DECDPUN!=3 /* not fast path */
627 Unit in; /* current unit */
628 #endif
629
630 if (shift!=0) { /* shift towards most significant required */
631 /* shift the units array to the left by pad digits and copy */
632 /* [this code is a special case of decShiftToMost, which could */
633 /* be used instead if exposed and the array were copied first] */
634 const Unit *source; /* .. */
635 Unit *target, *first; /* .. */
636 uInt next=0; /* work */
637
638 source=dn->lsu+D2U(digits)-1; /* where msu comes from */
639 target=uar+D2U(digits)-1+D2U(shift);/* where upper part of first cut goes */
640 cut=DECDPUN-MSUDIGITS(shift); /* where to slice */
641 if (cut==0) { /* unit-boundary case */
642 for (; source>=dn->lsu; source--, target--) *target=*source;
643 }
644 else {
645 first=uar+D2U(digits+shift)-1; /* where msu will end up */
646 for (; source>=dn->lsu; source--, target--) {
647 /* split the source Unit and accumulate remainder for next */
648 #if DECDPUN<=4
649 uInt quot=QUOT10(*source, cut);
650 uInt rem=*source-quot*DECPOWERS[cut];
651 next+=quot;
652 #else
653 uInt rem=*source%DECPOWERS[cut];
654 next+=*source/DECPOWERS[cut];
655 #endif
656 if (target<=first) *target=(Unit)next; /* write to target iff valid */
657 next=rem*DECPOWERS[DECDPUN-cut]; /* save remainder for next Unit */
658 }
659 } /* shift-move */
660 /* propagate remainder to one below and clear the rest */
661 for (; target>=uar; target--) {
662 *target=(Unit)next;
663 next=0;
664 }
665 digits+=shift; /* add count (shift) of zeros added */
666 inu=uar; /* use units in working array */
667 }
668
669 /* now densely pack the coefficient into DPD declets */
670
671 #if DECDPUN!=3 /* not fast path */
672 in=*inu; /* current unit */
673 cut=0; /* at lowest digit */
674 bin=0; /* [keep compiler quiet] */
675 #endif
676
677 for(n=0; digits>0; n++) { /* each output bunch */
678 #if DECDPUN==3 /* fast path, 3-at-a-time */
679 bin=*inu; /* 3 digits ready for convert */
680 digits-=3; /* [may go negative] */
681 inu++; /* may need another */
682
683 #else /* must collect digit-by-digit */
684 Unit dig; /* current digit */
685 Int j; /* digit-in-declet count */
686 for (j=0; j<3; j++) {
687 #if DECDPUN<=4
688 Unit temp=(Unit)((uInt)(in*6554)>>16);
689 dig=(Unit)(in-X10(temp));
690 in=temp;
691 #else
692 dig=in%10;
693 in=in/10;
694 #endif
695 if (j==0) bin=dig;
696 else if (j==1) bin+=X10(dig);
697 else /* j==2 */ bin+=X100(dig);
698 digits--;
699 if (digits==0) break; /* [also protects *inu below] */
700 cut++;
701 if (cut==DECDPUN) {inu++; in=*inu; cut=0;}
702 }
703 #endif
704 /* here there are 3 digits in bin, or have used all input digits */
705
706 dpd=BIN2DPD[bin];
707
708 /* write declet to uInt array */
709 *uout|=dpd<<uoff;
710 uoff+=10;
711 if (uoff<32) continue; /* no uInt boundary cross */
712 uout++;
713 uoff-=32;
714 *uout|=dpd>>(10-uoff); /* collect top bits */
715 } /* n declets */
716 return;
717 } /* decDigitsToDPD */
718
719 /* ------------------------------------------------------------------ */
720 /* decDigitsFromDPD -- unpack a format's coefficient */
721 /* */
722 /* dn is the target number, with 7, 16, or 34-digit space. */
723 /* sour is a 1, 2, or 4-element uInt array containing only declets */
724 /* declets is the number of (right-aligned) declets in sour to */
725 /* be processed. This may be 1 more than the obvious number in */
726 /* a format, as any top digit is prefixed to the coefficient */
727 /* continuation field. It also may be as small as 1, as the */
728 /* caller may pre-process leading zero declets. */
729 /* */
730 /* When doing the 'extra declet' case care is taken to avoid writing */
731 /* extra digits when there are leading zeros, as these could overflow */
732 /* the units array when DECDPUN is not 3. */
733 /* */
734 /* The target uInts are used only as necessary to process declets */
735 /* declets into the decNumber. When more than one uInt is needed, */
736 /* they are used from left to right (that is, the uInt at offset 0 */
737 /* provides the least-significant digits). */
738 /* */
739 /* dn->digits is set, but not the sign or exponent. */
740 /* No error is possible [the redundant 888 codes are allowed]. */
741 /* ------------------------------------------------------------------ */
742 void decDigitsFromDPD(decNumber *dn, const uInt *sour, Int declets) {
743
744 uInt dpd; /* collector for 10 bits */
745 Int n; /* counter */
746 Unit *uout=dn->lsu; /* -> current output unit */
747 Unit *last=uout; /* will be unit containing msd */
748 const uInt *uin=sour; /* -> current input uInt */
749 uInt uoff=0; /* -> current input offset [from right] */
750
751 #if DECDPUN!=3
752 uInt bcd; /* BCD result */
753 uInt nibble; /* work */
754 Unit out=0; /* accumulator */
755 Int cut=0; /* power of ten in current unit */
756 #endif
757 #if DECDPUN>4
758 uInt const *pow; /* work */
759 #endif
760
761 /* Expand the densely-packed integer, right to left */
762 for (n=declets-1; n>=0; n--) { /* count down declets of 10 bits */
763 dpd=*uin>>uoff;
764 uoff+=10;
765 if (uoff>32) { /* crossed uInt boundary */
766 uin++;
767 uoff-=32;
768 dpd|=*uin<<(10-uoff); /* get waiting bits */
769 }
770 dpd&=0x3ff; /* clear uninteresting bits */
771
772 #if DECDPUN==3
773 if (dpd==0) *uout=0;
774 else {
775 *uout=DPD2BIN[dpd]; /* convert 10 bits to binary 0-999 */
776 last=uout; /* record most significant unit */
777 }
778 uout++;
779 } /* n */
780
781 #else /* DECDPUN!=3 */
782 if (dpd==0) { /* fastpath [e.g., leading zeros] */
783 /* write out three 0 digits (nibbles); out may have digit(s) */
784 cut++;
785 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
786 if (n==0) break; /* [as below, works even if MSD=0] */
787 cut++;
788 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
789 cut++;
790 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
791 continue;
792 }
793
794 bcd=DPD2BCD[dpd]; /* convert 10 bits to 12 bits BCD */
795
796 /* now accumulate the 3 BCD nibbles into units */
797 nibble=bcd & 0x00f;
798 if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
799 cut++;
800 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
801 bcd>>=4;
802
803 /* if this is the last declet and the remaining nibbles in bcd */
804 /* are 00 then process no more nibbles, because this could be */
805 /* the 'odd' MSD declet and writing any more Units would then */
806 /* overflow the unit array */
807 if (n==0 && !bcd) break;
808
809 nibble=bcd & 0x00f;
810 if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
811 cut++;
812 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
813 bcd>>=4;
814
815 nibble=bcd & 0x00f;
816 if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
817 cut++;
818 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
819 } /* n */
820 if (cut!=0) { /* some more left over */
821 *uout=out; /* write out final unit */
822 if (out) last=uout; /* and note if non-zero */
823 }
824 #endif
825
826 /* here, last points to the most significant unit with digits; */
827 /* inspect it to get the final digits count -- this is essentially */
828 /* the same code as decGetDigits in decNumber.c */
829 dn->digits=(last-dn->lsu)*DECDPUN+1; /* floor of digits, plus */
830 /* must be at least 1 digit */
831 #if DECDPUN>1
832 if (*last<10) return; /* common odd digit or 0 */
833 dn->digits++; /* must be 2 at least */
834 #if DECDPUN>2
835 if (*last<100) return; /* 10-99 */
836 dn->digits++; /* must be 3 at least */
837 #if DECDPUN>3
838 if (*last<1000) return; /* 100-999 */
839 dn->digits++; /* must be 4 at least */
840 #if DECDPUN>4
841 for (pow=&DECPOWERS[4]; *last>=*pow; pow++) dn->digits++;
842 #endif
843 #endif
844 #endif
845 #endif
846 return;
847 } /*decDigitsFromDPD */