1 /* Decimal 64-bit format module for the decNumber C Library.
2 Copyright (C) 2005, 2007 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 2, or (at your option) any later
10 version.
11
12 In addition to the permissions in the GNU General Public License,
13 the Free Software Foundation gives you unlimited permission to link
14 the compiled version of this file into combinations with other
15 programs, and to distribute those combinations without any
16 restriction coming from the use of this file. (The General Public
17 License restrictions do apply in other respects; for example, they
18 cover modification of the file, and distribution when not linked
19 into a combine executable.)
20
21 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
22 WARRANTY; without even the implied warranty of MERCHANTABILITY or
23 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
24 for more details.
25
26 You should have received a copy of the GNU General Public License
27 along with GCC; see the file COPYING. If not, write to the Free
28 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
29 02110-1301, USA. */
30
31 /* ------------------------------------------------------------------ */
32 /* Decimal 64-bit format module */
33 /* ------------------------------------------------------------------ */
34 /* This module comprises the routines for decimal64 format numbers. */
35 /* Conversions are supplied to and from decNumber and String. */
36 /* */
37 /* This is used when decNumber provides operations, either for all */
38 /* operations or as a proxy between decNumber and decSingle. */
39 /* */
40 /* Error handling is the same as decNumber (qv.). */
41 /* ------------------------------------------------------------------ */
42 #include "qemu/osdep.h"
43
44 #include "libdecnumber/dconfig.h"
45 #define DECNUMDIGITS 16 /* make decNumbers with space for 16 */
46 #include "libdecnumber/decNumber.h"
47 #include "libdecnumber/decNumberLocal.h"
48 #include "libdecnumber/dpd/decimal64.h"
49
50 /* Utility routines and tables [in decimal64.c]; externs for C++ */
51 extern const uInt COMBEXP[32], COMBMSD[32];
52 extern const uByte BIN2CHAR[4001];
53
54 extern void decDigitsFromDPD(decNumber *, const uInt *, Int);
55 extern void decDigitsToDPD(const decNumber *, uInt *, Int);
56
57 #if DECTRACE || DECCHECK
58 void decimal64Show(const decimal64 *); /* for debug */
59 extern void decNumberShow(const decNumber *); /* .. */
60 #endif
61
62 /* Useful macro */
63 /* Clear a structure (e.g., a decNumber) */
64 #define DEC_clear(d) memset(d, 0, sizeof(*d))
65
66 /* define and include the tables to use for conversions */
67 #define DEC_BIN2CHAR 1
68 #define DEC_DPD2BIN 1
69 #define DEC_BIN2DPD 1 /* used for all sizes */
70 #include "libdecnumber/decDPD.h"
71
72 /* ------------------------------------------------------------------ */
73 /* decimal64FromNumber -- convert decNumber to decimal64 */
74 /* */
75 /* ds is the target decimal64 */
76 /* dn is the source number (assumed valid) */
77 /* set is the context, used only for reporting errors */
78 /* */
79 /* The set argument is used only for status reporting and for the */
80 /* rounding mode (used if the coefficient is more than DECIMAL64_Pmax */
81 /* digits or an overflow is detected). If the exponent is out of the */
82 /* valid range then Overflow or Underflow will be raised. */
83 /* After Underflow a subnormal result is possible. */
84 /* */
85 /* DEC_Clamped is set if the number has to be 'folded down' to fit, */
86 /* by reducing its exponent and multiplying the coefficient by a */
87 /* power of ten, or if the exponent on a zero had to be clamped. */
88 /* ------------------------------------------------------------------ */
decimal64FromNumber(decimal64 * d64,const decNumber * dn,decContext * set)89 decimal64 * decimal64FromNumber(decimal64 *d64, const decNumber *dn,
90 decContext *set) {
91 uInt status=0; /* status accumulator */
92 Int ae; /* adjusted exponent */
93 decNumber dw; /* work */
94 decContext dc; /* .. */
95 uInt *pu; /* .. */
96 uInt comb, exp; /* .. */
97 uInt targar[2]={0, 0}; /* target 64-bit */
98 #define targhi targar[1] /* name the word with the sign */
99 #define targlo targar[0] /* and the other */
100
101 /* If the number has too many digits, or the exponent could be */
102 /* out of range then reduce the number under the appropriate */
103 /* constraints. This could push the number to Infinity or zero, */
104 /* so this check and rounding must be done before generating the */
105 /* decimal64] */
106 ae=dn->exponent+dn->digits-1; /* [0 if special] */
107 if (dn->digits>DECIMAL64_Pmax /* too many digits */
108 || ae>DECIMAL64_Emax /* likely overflow */
109 || ae<DECIMAL64_Emin) { /* likely underflow */
110 decContextDefault(&dc, DEC_INIT_DECIMAL64); /* [no traps] */
111 dc.round=set->round; /* use supplied rounding */
112 decNumberPlus(&dw, dn, &dc); /* (round and check) */
113 /* [this changes -0 to 0, so enforce the sign...] */
114 dw.bits|=dn->bits&DECNEG;
115 status=dc.status; /* save status */
116 dn=&dw; /* use the work number */
117 } /* maybe out of range */
118
119 if (dn->bits&DECSPECIAL) { /* a special value */
120 if (dn->bits&DECINF) targhi=DECIMAL_Inf<<24;
121 else { /* sNaN or qNaN */
122 if ((*dn->lsu!=0 || dn->digits>1) /* non-zero coefficient */
123 && (dn->digits<DECIMAL64_Pmax)) { /* coefficient fits */
124 decDigitsToDPD(dn, targar, 0);
125 }
126 if (dn->bits&DECNAN) targhi|=DECIMAL_NaN<<24;
127 else targhi|=DECIMAL_sNaN<<24;
128 } /* a NaN */
129 } /* special */
130
131 else { /* is finite */
132 if (decNumberIsZero(dn)) { /* is a zero */
133 /* set and clamp exponent */
134 if (dn->exponent<-DECIMAL64_Bias) {
135 exp=0; /* low clamp */
136 status|=DEC_Clamped;
137 }
138 else {
139 exp=dn->exponent+DECIMAL64_Bias; /* bias exponent */
140 if (exp>DECIMAL64_Ehigh) { /* top clamp */
141 exp=DECIMAL64_Ehigh;
142 status|=DEC_Clamped;
143 }
144 }
145 comb=(exp>>5) & 0x18; /* msd=0, exp top 2 bits .. */
146 }
147 else { /* non-zero finite number */
148 uInt msd; /* work */
149 Int pad=0; /* coefficient pad digits */
150
151 /* the dn is known to fit, but it may need to be padded */
152 exp=(uInt)(dn->exponent+DECIMAL64_Bias); /* bias exponent */
153 if (exp>DECIMAL64_Ehigh) { /* fold-down case */
154 pad=exp-DECIMAL64_Ehigh;
155 exp=DECIMAL64_Ehigh; /* [to maximum] */
156 status|=DEC_Clamped;
157 }
158
159 /* fastpath common case */
160 if (DECDPUN==3 && pad==0) {
161 uInt dpd[6]={0,0,0,0,0,0};
162 uInt i;
163 Int d=dn->digits;
164 for (i=0; d>0; i++, d-=3) dpd[i]=BIN2DPD[dn->lsu[i]];
165 targlo =dpd[0];
166 targlo|=dpd[1]<<10;
167 targlo|=dpd[2]<<20;
168 if (dn->digits>6) {
169 targlo|=dpd[3]<<30;
170 targhi =dpd[3]>>2;
171 targhi|=dpd[4]<<8;
172 }
173 msd=dpd[5]; /* [did not really need conversion] */
174 }
175 else { /* general case */
176 decDigitsToDPD(dn, targar, pad);
177 /* save and clear the top digit */
178 msd=targhi>>18;
179 targhi&=0x0003ffff;
180 }
181
182 /* create the combination field */
183 if (msd>=8) comb=0x18 | ((exp>>7) & 0x06) | (msd & 0x01);
184 else comb=((exp>>5) & 0x18) | msd;
185 }
186 targhi|=comb<<26; /* add combination field .. */
187 targhi|=(exp&0xff)<<18; /* .. and exponent continuation */
188 } /* finite */
189
190 if (dn->bits&DECNEG) targhi|=0x80000000; /* add sign bit */
191
192 /* now write to storage; this is now always endian */
193 pu=(uInt *)d64->bytes; /* overlay */
194 if (DECLITEND) {
195 pu[0]=targar[0]; /* directly store the low int */
196 pu[1]=targar[1]; /* then the high int */
197 }
198 else {
199 pu[0]=targar[1]; /* directly store the high int */
200 pu[1]=targar[0]; /* then the low int */
201 }
202
203 if (status!=0) decContextSetStatus(set, status); /* pass on status */
204 /* decimal64Show(d64); */
205 return d64;
206 } /* decimal64FromNumber */
207
208 /* ------------------------------------------------------------------ */
209 /* decimal64ToNumber -- convert decimal64 to decNumber */
210 /* d64 is the source decimal64 */
211 /* dn is the target number, with appropriate space */
212 /* No error is possible. */
213 /* ------------------------------------------------------------------ */
decimal64ToNumber(const decimal64 * d64,decNumber * dn)214 decNumber * decimal64ToNumber(const decimal64 *d64, decNumber *dn) {
215 uInt msd; /* coefficient MSD */
216 uInt exp; /* exponent top two bits */
217 uInt comb; /* combination field */
218 const uInt *pu; /* work */
219 Int need; /* .. */
220 uInt sourar[2]; /* source 64-bit */
221 #define sourhi sourar[1] /* name the word with the sign */
222 #define sourlo sourar[0] /* and the lower word */
223
224 /* load source from storage; this is endian */
225 pu=(const uInt *)d64->bytes; /* overlay */
226 if (DECLITEND) {
227 sourlo=pu[0]; /* directly load the low int */
228 sourhi=pu[1]; /* then the high int */
229 }
230 else {
231 sourhi=pu[0]; /* directly load the high int */
232 sourlo=pu[1]; /* then the low int */
233 }
234
235 comb=(sourhi>>26)&0x1f; /* combination field */
236
237 decNumberZero(dn); /* clean number */
238 if (sourhi&0x80000000) dn->bits=DECNEG; /* set sign if negative */
239
240 msd=COMBMSD[comb]; /* decode the combination field */
241 exp=COMBEXP[comb]; /* .. */
242
243 if (exp==3) { /* is a special */
244 if (msd==0) {
245 dn->bits|=DECINF;
246 return dn; /* no coefficient needed */
247 }
248 else if (sourhi&0x02000000) dn->bits|=DECSNAN;
249 else dn->bits|=DECNAN;
250 msd=0; /* no top digit */
251 }
252 else { /* is a finite number */
253 dn->exponent=(exp<<8)+((sourhi>>18)&0xff)-DECIMAL64_Bias; /* unbiased */
254 }
255
256 /* get the coefficient */
257 sourhi&=0x0003ffff; /* clean coefficient continuation */
258 if (msd) { /* non-zero msd */
259 sourhi|=msd<<18; /* prefix to coefficient */
260 need=6; /* process 6 declets */
261 }
262 else { /* msd=0 */
263 if (!sourhi) { /* top word 0 */
264 if (!sourlo) return dn; /* easy: coefficient is 0 */
265 need=3; /* process at least 3 declets */
266 if (sourlo&0xc0000000) need++; /* process 4 declets */
267 /* [could reduce some more, here] */
268 }
269 else { /* some bits in top word, msd=0 */
270 need=4; /* process at least 4 declets */
271 if (sourhi&0x0003ff00) need++; /* top declet!=0, process 5 */
272 }
273 } /*msd=0 */
274
275 decDigitsFromDPD(dn, sourar, need); /* process declets */
276 return dn;
277 } /* decimal64ToNumber */
278
279
280 /* ------------------------------------------------------------------ */
281 /* to-scientific-string -- conversion to numeric string */
282 /* to-engineering-string -- conversion to numeric string */
283 /* */
284 /* decimal64ToString(d64, string); */
285 /* decimal64ToEngString(d64, string); */
286 /* */
287 /* d64 is the decimal64 format number to convert */
288 /* string is the string where the result will be laid out */
289 /* */
290 /* string must be at least 24 characters */
291 /* */
292 /* No error is possible, and no status can be set. */
293 /* ------------------------------------------------------------------ */
decimal64ToEngString(const decimal64 * d64,char * string)294 char * decimal64ToEngString(const decimal64 *d64, char *string){
295 decNumber dn; /* work */
296 decimal64ToNumber(d64, &dn);
297 decNumberToEngString(&dn, string);
298 return string;
299 } /* decimal64ToEngString */
300
decimal64ToString(const decimal64 * d64,char * string)301 char * decimal64ToString(const decimal64 *d64, char *string){
302 uInt msd; /* coefficient MSD */
303 Int exp; /* exponent top two bits or full */
304 uInt comb; /* combination field */
305 char *cstart; /* coefficient start */
306 char *c; /* output pointer in string */
307 const uInt *pu; /* work */
308 char *s, *t; /* .. (source, target) */
309 Int dpd; /* .. */
310 Int pre, e; /* .. */
311 const uByte *u; /* .. */
312
313 uInt sourar[2]; /* source 64-bit */
314 #define sourhi sourar[1] /* name the word with the sign */
315 #define sourlo sourar[0] /* and the lower word */
316
317 /* load source from storage; this is endian */
318 pu=(const uInt *)d64->bytes; /* overlay */
319 if (DECLITEND) {
320 sourlo=pu[0]; /* directly load the low int */
321 sourhi=pu[1]; /* then the high int */
322 }
323 else {
324 sourhi=pu[0]; /* directly load the high int */
325 sourlo=pu[1]; /* then the low int */
326 }
327
328 c=string; /* where result will go */
329 if (((Int)sourhi)<0) *c++='-'; /* handle sign */
330
331 comb=(sourhi>>26)&0x1f; /* combination field */
332 msd=COMBMSD[comb]; /* decode the combination field */
333 exp=COMBEXP[comb]; /* .. */
334
335 if (exp==3) {
336 if (msd==0) { /* infinity */
337 strcpy(c, "Inf");
338 strcpy(c+3, "inity");
339 return string; /* easy */
340 }
341 if (sourhi&0x02000000) *c++='s'; /* sNaN */
342 strcpy(c, "NaN"); /* complete word */
343 c+=3; /* step past */
344 if (sourlo==0 && (sourhi&0x0003ffff)==0) return string; /* zero payload */
345 /* otherwise drop through to add integer; set correct exp */
346 exp=0; msd=0; /* setup for following code */
347 }
348 else exp=(exp<<8)+((sourhi>>18)&0xff)-DECIMAL64_Bias;
349
350 /* convert 16 digits of significand to characters */
351 cstart=c; /* save start of coefficient */
352 if (msd) *c++='0'+(char)msd; /* non-zero most significant digit */
353
354 /* Now decode the declets. After extracting each one, it is */
355 /* decoded to binary and then to a 4-char sequence by table lookup; */
356 /* the 4-chars are a 1-char length (significant digits, except 000 */
357 /* has length 0). This allows us to left-align the first declet */
358 /* with non-zero content, then remaining ones are full 3-char */
359 /* length. We use fixed-length memcpys because variable-length */
360 /* causes a subroutine call in GCC. (These are length 4 for speed */
361 /* and are safe because the array has an extra terminator byte.) */
362 #define dpd2char u=&BIN2CHAR[DPD2BIN[dpd]*4]; \
363 if (c!=cstart) {memcpy(c, u+1, 4); c+=3;} \
364 else if (*u) {memcpy(c, u+4-*u, 4); c+=*u;}
365
366 dpd=(sourhi>>8)&0x3ff; /* declet 1 */
367 dpd2char;
368 dpd=((sourhi&0xff)<<2) | (sourlo>>30); /* declet 2 */
369 dpd2char;
370 dpd=(sourlo>>20)&0x3ff; /* declet 3 */
371 dpd2char;
372 dpd=(sourlo>>10)&0x3ff; /* declet 4 */
373 dpd2char;
374 dpd=(sourlo)&0x3ff; /* declet 5 */
375 dpd2char;
376
377 if (c==cstart) *c++='0'; /* all zeros -- make 0 */
378
379 if (exp==0) { /* integer or NaN case -- easy */
380 *c='\0'; /* terminate */
381 return string;
382 }
383
384 /* non-0 exponent */
385 e=0; /* assume no E */
386 pre=c-cstart+exp;
387 /* [here, pre-exp is the digits count (==1 for zero)] */
388 if (exp>0 || pre<-5) { /* need exponential form */
389 e=pre-1; /* calculate E value */
390 pre=1; /* assume one digit before '.' */
391 } /* exponential form */
392
393 /* modify the coefficient, adding 0s, '.', and E+nn as needed */
394 s=c-1; /* source (LSD) */
395 if (pre>0) { /* ddd.ddd (plain), perhaps with E */
396 char *dotat=cstart+pre;
397 if (dotat<c) { /* if embedded dot needed... */
398 t=c; /* target */
399 for (; s>=dotat; s--, t--) *t=*s; /* open the gap; leave t at gap */
400 *t='.'; /* insert the dot */
401 c++; /* length increased by one */
402 }
403
404 /* finally add the E-part, if needed; it will never be 0, and has */
405 /* a maximum length of 3 digits */
406 if (e!=0) {
407 *c++='E'; /* starts with E */
408 *c++='+'; /* assume positive */
409 if (e<0) {
410 *(c-1)='-'; /* oops, need '-' */
411 e=-e; /* uInt, please */
412 }
413 u=&BIN2CHAR[e*4]; /* -> length byte */
414 memcpy(c, u+4-*u, 4); /* copy fixed 4 characters [is safe] */
415 c+=*u; /* bump pointer appropriately */
416 }
417 *c='\0'; /* add terminator */
418 /*printf("res %s\n", string); */
419 return string;
420 } /* pre>0 */
421
422 /* -5<=pre<=0: here for plain 0.ddd or 0.000ddd forms (can never have E) */
423 t=c+1-pre;
424 *(t+1)='\0'; /* can add terminator now */
425 for (; s>=cstart; s--, t--) *t=*s; /* shift whole coefficient right */
426 c=cstart;
427 *c++='0'; /* always starts with 0. */
428 *c++='.';
429 for (; pre<0; pre++) *c++='0'; /* add any 0's after '.' */
430 /*printf("res %s\n", string); */
431 return string;
432 } /* decimal64ToString */
433
434 /* ------------------------------------------------------------------ */
435 /* to-number -- conversion from numeric string */
436 /* */
437 /* decimal64FromString(result, string, set); */
438 /* */
439 /* result is the decimal64 format number which gets the result of */
440 /* the conversion */
441 /* *string is the character string which should contain a valid */
442 /* number (which may be a special value) */
443 /* set is the context */
444 /* */
445 /* The context is supplied to this routine is used for error handling */
446 /* (setting of status and traps) and for the rounding mode, only. */
447 /* If an error occurs, the result will be a valid decimal64 NaN. */
448 /* ------------------------------------------------------------------ */
decimal64FromString(decimal64 * result,const char * string,decContext * set)449 decimal64 * decimal64FromString(decimal64 *result, const char *string,
450 decContext *set) {
451 decContext dc; /* work */
452 decNumber dn; /* .. */
453
454 decContextDefault(&dc, DEC_INIT_DECIMAL64); /* no traps, please */
455 dc.round=set->round; /* use supplied rounding */
456
457 decNumberFromString(&dn, string, &dc); /* will round if needed */
458
459 decimal64FromNumber(result, &dn, &dc);
460 if (dc.status!=0) { /* something happened */
461 decContextSetStatus(set, dc.status); /* .. pass it on */
462 }
463 return result;
464 } /* decimal64FromString */
465
466 /* ------------------------------------------------------------------ */
467 /* decimal64IsCanonical -- test whether encoding is canonical */
468 /* d64 is the source decimal64 */
469 /* returns 1 if the encoding of d64 is canonical, 0 otherwise */
470 /* No error is possible. */
471 /* ------------------------------------------------------------------ */
decimal64IsCanonical(const decimal64 * d64)472 uint32_t decimal64IsCanonical(const decimal64 *d64) {
473 decNumber dn; /* work */
474 decimal64 canon; /* .. */
475 decContext dc; /* .. */
476 decContextDefault(&dc, DEC_INIT_DECIMAL64);
477 decimal64ToNumber(d64, &dn);
478 decimal64FromNumber(&canon, &dn, &dc);/* canon will now be canonical */
479 return memcmp(d64, &canon, DECIMAL64_Bytes)==0;
480 } /* decimal64IsCanonical */
481
482 /* ------------------------------------------------------------------ */
483 /* decimal64Canonical -- copy an encoding, ensuring it is canonical */
484 /* d64 is the source decimal64 */
485 /* result is the target (may be the same decimal64) */
486 /* returns result */
487 /* No error is possible. */
488 /* ------------------------------------------------------------------ */
decimal64Canonical(decimal64 * result,const decimal64 * d64)489 decimal64 * decimal64Canonical(decimal64 *result, const decimal64 *d64) {
490 decNumber dn; /* work */
491 decContext dc; /* .. */
492 decContextDefault(&dc, DEC_INIT_DECIMAL64);
493 decimal64ToNumber(d64, &dn);
494 decimal64FromNumber(result, &dn, &dc);/* result will now be canonical */
495 return result;
496 } /* decimal64Canonical */
497
498 #if DECTRACE || DECCHECK
499 /* Macros for accessing decimal64 fields. These assume the
500 argument is a reference (pointer) to the decimal64 structure,
501 and the decimal64 is in network byte order (big-endian) */
502 /* Get sign */
503 #define decimal64Sign(d) ((unsigned)(d)->bytes[0]>>7)
504
505 /* Get combination field */
506 #define decimal64Comb(d) (((d)->bytes[0] & 0x7c)>>2)
507
508 /* Get exponent continuation [does not remove bias] */
509 #define decimal64ExpCon(d) ((((d)->bytes[0] & 0x03)<<6) \
510 | ((unsigned)(d)->bytes[1]>>2))
511
512 /* Set sign [this assumes sign previously 0] */
513 #define decimal64SetSign(d, b) { \
514 (d)->bytes[0]|=((unsigned)(b)<<7);}
515
516 /* Set exponent continuation [does not apply bias] */
517 /* This assumes range has been checked and exponent previously 0; */
518 /* type of exponent must be unsigned */
519 #define decimal64SetExpCon(d, e) { \
520 (d)->bytes[0]|=(uint8_t)((e)>>6); \
521 (d)->bytes[1]|=(uint8_t)(((e)&0x3F)<<2);}
522
523 /* ------------------------------------------------------------------ */
524 /* decimal64Show -- display a decimal64 in hexadecimal [debug aid] */
525 /* d64 -- the number to show */
526 /* ------------------------------------------------------------------ */
527 /* Also shows sign/cob/expconfields extracted */
decimal64Show(const decimal64 * d64)528 void decimal64Show(const decimal64 *d64) {
529 char buf[DECIMAL64_Bytes*2+1];
530 Int i, j=0;
531
532 if (DECLITEND) {
533 for (i=0; i<DECIMAL64_Bytes; i++, j+=2) {
534 sprintf(&buf[j], "%02x", d64->bytes[7-i]);
535 }
536 printf(" D64> %s [S:%d Cb:%02x Ec:%02x] LittleEndian\n", buf,
537 d64->bytes[7]>>7, (d64->bytes[7]>>2)&0x1f,
538 ((d64->bytes[7]&0x3)<<6)| (d64->bytes[6]>>2));
539 }
540 else { /* big-endian */
541 for (i=0; i<DECIMAL64_Bytes; i++, j+=2) {
542 sprintf(&buf[j], "%02x", d64->bytes[i]);
543 }
544 printf(" D64> %s [S:%d Cb:%02x Ec:%02x] BigEndian\n", buf,
545 decimal64Sign(d64), decimal64Comb(d64), decimal64ExpCon(d64));
546 }
547 } /* decimal64Show */
548 #endif
549
550 /* ================================================================== */
551 /* Shared utility routines and tables */
552 /* ================================================================== */
553 /* define and include the conversion tables to use for shared code */
554 #if DECDPUN==3
555 #define DEC_DPD2BIN 1
556 #else
557 #define DEC_DPD2BCD 1
558 #endif
559 #include "libdecnumber/decDPD.h"
560
561 /* The maximum number of decNumberUnits needed for a working copy of */
562 /* the units array is the ceiling of digits/DECDPUN, where digits is */
563 /* the maximum number of digits in any of the formats for which this */
564 /* is used. decimal128.h must not be included in this module, so, as */
565 /* a very special case, that number is defined as a literal here. */
566 #define DECMAX754 34
567 #define DECMAXUNITS ((DECMAX754+DECDPUN-1)/DECDPUN)
568
569 /* ------------------------------------------------------------------ */
570 /* Combination field lookup tables (uInts to save measurable work) */
571 /* */
572 /* COMBEXP - 2-bit most-significant-bits of exponent */
573 /* [11 if an Infinity or NaN] */
574 /* COMBMSD - 4-bit most-significant-digit */
575 /* [0=Infinity, 1=NaN if COMBEXP=11] */
576 /* */
577 /* Both are indexed by the 5-bit combination field (0-31) */
578 /* ------------------------------------------------------------------ */
579 const uInt COMBEXP[32]={0, 0, 0, 0, 0, 0, 0, 0,
580 1, 1, 1, 1, 1, 1, 1, 1,
581 2, 2, 2, 2, 2, 2, 2, 2,
582 0, 0, 1, 1, 2, 2, 3, 3};
583 const uInt COMBMSD[32]={0, 1, 2, 3, 4, 5, 6, 7,
584 0, 1, 2, 3, 4, 5, 6, 7,
585 0, 1, 2, 3, 4, 5, 6, 7,
586 8, 9, 8, 9, 8, 9, 0, 1};
587
588 /* ------------------------------------------------------------------ */
589 /* decDigitsToDPD -- pack coefficient into DPD form */
590 /* */
591 /* dn is the source number (assumed valid, max DECMAX754 digits) */
592 /* targ is 1, 2, or 4-element uInt array, which the caller must */
593 /* have cleared to zeros */
594 /* shift is the number of 0 digits to add on the right (normally 0) */
595 /* */
596 /* The coefficient must be known small enough to fit. The full */
597 /* coefficient is copied, including the leading 'odd' digit. This */
598 /* digit is retrieved and packed into the combination field by the */
599 /* caller. */
600 /* */
601 /* The target uInts are altered only as necessary to receive the */
602 /* digits of the decNumber. When more than one uInt is needed, they */
603 /* are filled from left to right (that is, the uInt at offset 0 will */
604 /* end up with the least-significant digits). */
605 /* */
606 /* shift is used for 'fold-down' padding. */
607 /* */
608 /* No error is possible. */
609 /* ------------------------------------------------------------------ */
610 #if DECDPUN<=4
611 /* Constant multipliers for divide-by-power-of five using reciprocal */
612 /* multiply, after removing powers of 2 by shifting, and final shift */
613 /* of 17 [we only need up to **4] */
614 static const uInt multies[]={131073, 26215, 5243, 1049, 210};
615 /* QUOT10 -- macro to return the quotient of unit u divided by 10**n */
616 #define QUOT10(u, n) ((((uInt)(u)>>(n))*multies[n])>>17)
617 #endif
decDigitsToDPD(const decNumber * dn,uInt * targ,Int shift)618 void decDigitsToDPD(const decNumber *dn, uInt *targ, Int shift) {
619 Int cut; /* work */
620 Int digits=dn->digits; /* digit countdown */
621 uInt dpd; /* densely packed decimal value */
622 uInt bin; /* binary value 0-999 */
623 uInt *uout=targ; /* -> current output uInt */
624 uInt uoff=0; /* -> current output offset [from right] */
625 const Unit *inu=dn->lsu; /* -> current input unit */
626 Unit uar[DECMAXUNITS]; /* working copy of units, iff shifted */
627 #if DECDPUN!=3 /* not fast path */
628 Unit in; /* current unit */
629 #endif
630
631 if (shift!=0) { /* shift towards most significant required */
632 /* shift the units array to the left by pad digits and copy */
633 /* [this code is a special case of decShiftToMost, which could */
634 /* be used instead if exposed and the array were copied first] */
635 const Unit *source; /* .. */
636 Unit *target, *first; /* .. */
637 uInt next=0; /* work */
638
639 source=dn->lsu+D2U(digits)-1; /* where msu comes from */
640 target=uar+D2U(digits)-1+D2U(shift);/* where upper part of first cut goes */
641 cut=DECDPUN-MSUDIGITS(shift); /* where to slice */
642 if (cut==0) { /* unit-boundary case */
643 for (; source>=dn->lsu; source--, target--) *target=*source;
644 }
645 else {
646 first=uar+D2U(digits+shift)-1; /* where msu will end up */
647 for (; source>=dn->lsu; source--, target--) {
648 /* split the source Unit and accumulate remainder for next */
649 #if DECDPUN<=4
650 uInt quot=QUOT10(*source, cut);
651 uInt rem=*source-quot*DECPOWERS[cut];
652 next+=quot;
653 #else
654 uInt rem=*source%DECPOWERS[cut];
655 next+=*source/DECPOWERS[cut];
656 #endif
657 if (target<=first) *target=(Unit)next; /* write to target iff valid */
658 next=rem*DECPOWERS[DECDPUN-cut]; /* save remainder for next Unit */
659 }
660 } /* shift-move */
661 /* propagate remainder to one below and clear the rest */
662 for (; target>=uar; target--) {
663 *target=(Unit)next;
664 next=0;
665 }
666 digits+=shift; /* add count (shift) of zeros added */
667 inu=uar; /* use units in working array */
668 }
669
670 /* now densely pack the coefficient into DPD declets */
671
672 #if DECDPUN!=3 /* not fast path */
673 in=*inu; /* current unit */
674 cut=0; /* at lowest digit */
675 bin=0; /* [keep compiler quiet] */
676 #endif
677
678 while (digits > 0) { /* each output bunch */
679 #if DECDPUN==3 /* fast path, 3-at-a-time */
680 bin=*inu; /* 3 digits ready for convert */
681 digits-=3; /* [may go negative] */
682 inu++; /* may need another */
683
684 #else /* must collect digit-by-digit */
685 Unit dig; /* current digit */
686 Int j; /* digit-in-declet count */
687 for (j=0; j<3; j++) {
688 #if DECDPUN<=4
689 Unit temp=(Unit)((uInt)(in*6554)>>16);
690 dig=(Unit)(in-X10(temp));
691 in=temp;
692 #else
693 dig=in%10;
694 in=in/10;
695 #endif
696 if (j==0) bin=dig;
697 else if (j==1) bin+=X10(dig);
698 else /* j==2 */ bin+=X100(dig);
699 digits--;
700 if (digits==0) break; /* [also protects *inu below] */
701 cut++;
702 if (cut==DECDPUN) {inu++; in=*inu; cut=0;}
703 }
704 #endif
705 /* here there are 3 digits in bin, or have used all input digits */
706
707 dpd=BIN2DPD[bin];
708
709 /* write declet to uInt array */
710 *uout|=dpd<<uoff;
711 uoff+=10;
712 if (uoff<32) continue; /* no uInt boundary cross */
713 uout++;
714 uoff-=32;
715 *uout|=dpd>>(10-uoff); /* collect top bits */
716 } /* n declets */
717 return;
718 } /* decDigitsToDPD */
719
720 /* ------------------------------------------------------------------ */
721 /* decDigitsFromDPD -- unpack a format's coefficient */
722 /* */
723 /* dn is the target number, with 7, 16, or 34-digit space. */
724 /* sour is a 1, 2, or 4-element uInt array containing only declets */
725 /* declets is the number of (right-aligned) declets in sour to */
726 /* be processed. This may be 1 more than the obvious number in */
727 /* a format, as any top digit is prefixed to the coefficient */
728 /* continuation field. It also may be as small as 1, as the */
729 /* caller may pre-process leading zero declets. */
730 /* */
731 /* When doing the 'extra declet' case care is taken to avoid writing */
732 /* extra digits when there are leading zeros, as these could overflow */
733 /* the units array when DECDPUN is not 3. */
734 /* */
735 /* The target uInts are used only as necessary to process declets */
736 /* declets into the decNumber. When more than one uInt is needed, */
737 /* they are used from left to right (that is, the uInt at offset 0 */
738 /* provides the least-significant digits). */
739 /* */
740 /* dn->digits is set, but not the sign or exponent. */
741 /* No error is possible [the redundant 888 codes are allowed]. */
742 /* ------------------------------------------------------------------ */
decDigitsFromDPD(decNumber * dn,const uInt * sour,Int declets)743 void decDigitsFromDPD(decNumber *dn, const uInt *sour, Int declets) {
744
745 uInt dpd; /* collector for 10 bits */
746 Int n; /* counter */
747 Unit *uout=dn->lsu; /* -> current output unit */
748 Unit *last=uout; /* will be unit containing msd */
749 const uInt *uin=sour; /* -> current input uInt */
750 uInt uoff=0; /* -> current input offset [from right] */
751
752 #if DECDPUN!=3
753 uInt bcd; /* BCD result */
754 uInt nibble; /* work */
755 Unit out=0; /* accumulator */
756 Int cut=0; /* power of ten in current unit */
757 #endif
758 #if DECDPUN>4
759 uInt const *pow; /* work */
760 #endif
761
762 /* Expand the densely-packed integer, right to left */
763 for (n=declets-1; n>=0; n--) { /* count down declets of 10 bits */
764 dpd=*uin>>uoff;
765 uoff+=10;
766 if (uoff>32) { /* crossed uInt boundary */
767 uin++;
768 uoff-=32;
769 dpd|=*uin<<(10-uoff); /* get waiting bits */
770 }
771 dpd&=0x3ff; /* clear uninteresting bits */
772
773 #if DECDPUN==3
774 if (dpd==0) *uout=0;
775 else {
776 *uout=DPD2BIN[dpd]; /* convert 10 bits to binary 0-999 */
777 last=uout; /* record most significant unit */
778 }
779 uout++;
780 } /* n */
781
782 #else /* DECDPUN!=3 */
783 if (dpd==0) { /* fastpath [e.g., leading zeros] */
784 /* write out three 0 digits (nibbles); out may have digit(s) */
785 cut++;
786 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
787 if (n==0) break; /* [as below, works even if MSD=0] */
788 cut++;
789 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
790 cut++;
791 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
792 continue;
793 }
794
795 bcd=DPD2BCD[dpd]; /* convert 10 bits to 12 bits BCD */
796
797 /* now accumulate the 3 BCD nibbles into units */
798 nibble=bcd & 0x00f;
799 if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
800 cut++;
801 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
802 bcd>>=4;
803
804 /* if this is the last declet and the remaining nibbles in bcd */
805 /* are 00 then process no more nibbles, because this could be */
806 /* the 'odd' MSD declet and writing any more Units would then */
807 /* overflow the unit array */
808 if (n==0 && !bcd) break;
809
810 nibble=bcd & 0x00f;
811 if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
812 cut++;
813 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
814 bcd>>=4;
815
816 nibble=bcd & 0x00f;
817 if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
818 cut++;
819 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
820 } /* n */
821 if (cut!=0) { /* some more left over */
822 *uout=out; /* write out final unit */
823 if (out) last=uout; /* and note if non-zero */
824 }
825 #endif
826
827 /* here, last points to the most significant unit with digits; */
828 /* inspect it to get the final digits count -- this is essentially */
829 /* the same code as decGetDigits in decNumber.c */
830 dn->digits=(last-dn->lsu)*DECDPUN+1; /* floor of digits, plus */
831 /* must be at least 1 digit */
832 #if DECDPUN>1
833 if (*last<10) return; /* common odd digit or 0 */
834 dn->digits++; /* must be 2 at least */
835 #if DECDPUN>2
836 if (*last<100) return; /* 10-99 */
837 dn->digits++; /* must be 3 at least */
838 #if DECDPUN>3
839 if (*last<1000) return; /* 100-999 */
840 dn->digits++; /* must be 4 at least */
841 #if DECDPUN>4
842 for (pow=&DECPOWERS[4]; *last>=*pow; pow++) dn->digits++;
843 #endif
844 #endif
845 #endif
846 #endif
847 return;
848 } /*decDigitsFromDPD */
849