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maint: remove double semicolons in many files
[qemu/ar7.git] / libdecnumber / dpd / decimal64.c
blob8256084e90069822810b7847c3c79c34df3a42a3
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 <string.h> /* [for memset/memcpy] */
43 #include <stdio.h> /* [for printf] */
44
45 #include "libdecnumber/dconfig.h"
46 #define DECNUMDIGITS 16 /* make decNumbers with space for 16 */
47 #include "libdecnumber/decNumber.h"
48 #include "libdecnumber/decNumberLocal.h"
49 #include "libdecnumber/dpd/decimal64.h"
50
51 /* Utility routines and tables [in decimal64.c]; externs for C++ */
52 extern const uInt COMBEXP[32], COMBMSD[32];
53 extern const uByte BIN2CHAR[4001];
54
55 extern void decDigitsFromDPD(decNumber *, const uInt *, Int);
56 extern void decDigitsToDPD(const decNumber *, uInt *, Int);
57
58 #if DECTRACE || DECCHECK
59 void decimal64Show(const decimal64 *); /* for debug */
60 extern void decNumberShow(const decNumber *); /* .. */
61 #endif
62
63 /* Useful macro */
64 /* Clear a structure (e.g., a decNumber) */
65 #define DEC_clear(d) memset(d, 0, sizeof(*d))
66
67 /* define and include the tables to use for conversions */
68 #define DEC_BIN2CHAR 1
69 #define DEC_DPD2BIN 1
70 #define DEC_BIN2DPD 1 /* used for all sizes */
71 #include "libdecnumber/decDPD.h"
72
73 /* ------------------------------------------------------------------ */
74 /* decimal64FromNumber -- convert decNumber to decimal64 */
75 /* */
76 /* ds is the target decimal64 */
77 /* dn is the source number (assumed valid) */
78 /* set is the context, used only for reporting errors */
79 /* */
80 /* The set argument is used only for status reporting and for the */
81 /* rounding mode (used if the coefficient is more than DECIMAL64_Pmax */
82 /* digits or an overflow is detected). If the exponent is out of the */
83 /* valid range then Overflow or Underflow will be raised. */
84 /* After Underflow a subnormal result is possible. */
85 /* */
86 /* DEC_Clamped is set if the number has to be 'folded down' to fit, */
87 /* by reducing its exponent and multiplying the coefficient by a */
88 /* power of ten, or if the exponent on a zero had to be clamped. */
89 /* ------------------------------------------------------------------ */
90 decimal64 * decimal64FromNumber(decimal64 *d64, const decNumber *dn,
91 decContext *set) {
92 uInt status=0; /* status accumulator */
93 Int ae; /* adjusted exponent */
94 decNumber dw; /* work */
95 decContext dc; /* .. */
96 uInt *pu; /* .. */
97 uInt comb, exp; /* .. */
98 uInt targar[2]={0, 0}; /* target 64-bit */
99 #define targhi targar[1] /* name the word with the sign */
100 #define targlo targar[0] /* and the other */
101
102 /* If the number has too many digits, or the exponent could be */
103 /* out of range then reduce the number under the appropriate */
104 /* constraints. This could push the number to Infinity or zero, */
105 /* so this check and rounding must be done before generating the */
106 /* decimal64] */
107 ae=dn->exponent+dn->digits-1; /* [0 if special] */
108 if (dn->digits>DECIMAL64_Pmax /* too many digits */
109 || ae>DECIMAL64_Emax /* likely overflow */
110 || ae<DECIMAL64_Emin) { /* likely underflow */
111 decContextDefault(&dc, DEC_INIT_DECIMAL64); /* [no traps] */
112 dc.round=set->round; /* use supplied rounding */
113 decNumberPlus(&dw, dn, &dc); /* (round and check) */
114 /* [this changes -0 to 0, so enforce the sign...] */
115 dw.bits|=dn->bits&DECNEG;
116 status=dc.status; /* save status */
117 dn=&dw; /* use the work number */
118 } /* maybe out of range */
119
120 if (dn->bits&DECSPECIAL) { /* a special value */
121 if (dn->bits&DECINF) targhi=DECIMAL_Inf<<24;
122 else { /* sNaN or qNaN */
123 if ((*dn->lsu!=0 || dn->digits>1) /* non-zero coefficient */
124 && (dn->digits<DECIMAL64_Pmax)) { /* coefficient fits */
125 decDigitsToDPD(dn, targar, 0);
126 }
127 if (dn->bits&DECNAN) targhi|=DECIMAL_NaN<<24;
128 else targhi|=DECIMAL_sNaN<<24;
129 } /* a NaN */
130 } /* special */
131
132 else { /* is finite */
133 if (decNumberIsZero(dn)) { /* is a zero */
134 /* set and clamp exponent */
135 if (dn->exponent<-DECIMAL64_Bias) {
136 exp=0; /* low clamp */
137 status|=DEC_Clamped;
138 }
139 else {
140 exp=dn->exponent+DECIMAL64_Bias; /* bias exponent */
141 if (exp>DECIMAL64_Ehigh) { /* top clamp */
142 exp=DECIMAL64_Ehigh;
143 status|=DEC_Clamped;
144 }
145 }
146 comb=(exp>>5) & 0x18; /* msd=0, exp top 2 bits .. */
147 }
148 else { /* non-zero finite number */
149 uInt msd; /* work */
150 Int pad=0; /* coefficient pad digits */
151
152 /* the dn is known to fit, but it may need to be padded */
153 exp=(uInt)(dn->exponent+DECIMAL64_Bias); /* bias exponent */
154 if (exp>DECIMAL64_Ehigh) { /* fold-down case */
155 pad=exp-DECIMAL64_Ehigh;
156 exp=DECIMAL64_Ehigh; /* [to maximum] */
157 status|=DEC_Clamped;
158 }
159
160 /* fastpath common case */
161 if (DECDPUN==3 && pad==0) {
162 uInt dpd[6]={0,0,0,0,0,0};
163 uInt i;
164 Int d=dn->digits;
165 for (i=0; d>0; i++, d-=3) dpd[i]=BIN2DPD[dn->lsu[i]];
166 targlo =dpd[0];
167 targlo|=dpd[1]<<10;
168 targlo|=dpd[2]<<20;
169 if (dn->digits>6) {
170 targlo|=dpd[3]<<30;
171 targhi =dpd[3]>>2;
172 targhi|=dpd[4]<<8;
173 }
174 msd=dpd[5]; /* [did not really need conversion] */
175 }
176 else { /* general case */
177 decDigitsToDPD(dn, targar, pad);
178 /* save and clear the top digit */
179 msd=targhi>>18;
180 targhi&=0x0003ffff;
181 }
182
183 /* create the combination field */
184 if (msd>=8) comb=0x18 | ((exp>>7) & 0x06) | (msd & 0x01);
185 else comb=((exp>>5) & 0x18) | msd;
186 }
187 targhi|=comb<<26; /* add combination field .. */
188 targhi|=(exp&0xff)<<18; /* .. and exponent continuation */
189 } /* finite */
190
191 if (dn->bits&DECNEG) targhi|=0x80000000; /* add sign bit */
192
193 /* now write to storage; this is now always endian */
194 pu=(uInt *)d64->bytes; /* overlay */
195 if (DECLITEND) {
196 pu[0]=targar[0]; /* directly store the low int */
197 pu[1]=targar[1]; /* then the high int */
198 }
199 else {
200 pu[0]=targar[1]; /* directly store the high int */
201 pu[1]=targar[0]; /* then the low int */
202 }
203
204 if (status!=0) decContextSetStatus(set, status); /* pass on status */
205 /* decimal64Show(d64); */
206 return d64;
207 } /* decimal64FromNumber */
208
209 /* ------------------------------------------------------------------ */
210 /* decimal64ToNumber -- convert decimal64 to decNumber */
211 /* d64 is the source decimal64 */
212 /* dn is the target number, with appropriate space */
213 /* No error is possible. */
214 /* ------------------------------------------------------------------ */
215 decNumber * decimal64ToNumber(const decimal64 *d64, decNumber *dn) {
216 uInt msd; /* coefficient MSD */
217 uInt exp; /* exponent top two bits */
218 uInt comb; /* combination field */
219 const uInt *pu; /* work */
220 Int need; /* .. */
221 uInt sourar[2]; /* source 64-bit */
222 #define sourhi sourar[1] /* name the word with the sign */
223 #define sourlo sourar[0] /* and the lower word */
224
225 /* load source from storage; this is endian */
226 pu=(const uInt *)d64->bytes; /* overlay */
227 if (DECLITEND) {
228 sourlo=pu[0]; /* directly load the low int */
229 sourhi=pu[1]; /* then the high int */
230 }
231 else {
232 sourhi=pu[0]; /* directly load the high int */
233 sourlo=pu[1]; /* then the low int */
234 }
235
236 comb=(sourhi>>26)&0x1f; /* combination field */
237
238 decNumberZero(dn); /* clean number */
239 if (sourhi&0x80000000) dn->bits=DECNEG; /* set sign if negative */
240
241 msd=COMBMSD[comb]; /* decode the combination field */
242 exp=COMBEXP[comb]; /* .. */
243
244 if (exp==3) { /* is a special */
245 if (msd==0) {
246 dn->bits|=DECINF;
247 return dn; /* no coefficient needed */
248 }
249 else if (sourhi&0x02000000) dn->bits|=DECSNAN;
250 else dn->bits|=DECNAN;
251 msd=0; /* no top digit */
252 }
253 else { /* is a finite number */
254 dn->exponent=(exp<<8)+((sourhi>>18)&0xff)-DECIMAL64_Bias; /* unbiased */
255 }
256
257 /* get the coefficient */
258 sourhi&=0x0003ffff; /* clean coefficient continuation */
259 if (msd) { /* non-zero msd */
260 sourhi|=msd<<18; /* prefix to coefficient */
261 need=6; /* process 6 declets */
262 }
263 else { /* msd=0 */
264 if (!sourhi) { /* top word 0 */
265 if (!sourlo) return dn; /* easy: coefficient is 0 */
266 need=3; /* process at least 3 declets */
267 if (sourlo&0xc0000000) need++; /* process 4 declets */
268 /* [could reduce some more, here] */
269 }
270 else { /* some bits in top word, msd=0 */
271 need=4; /* process at least 4 declets */
272 if (sourhi&0x0003ff00) need++; /* top declet!=0, process 5 */
273 }
274 } /*msd=0 */
275
276 decDigitsFromDPD(dn, sourar, need); /* process declets */
277 return dn;
278 } /* decimal64ToNumber */
279
280
281 /* ------------------------------------------------------------------ */
282 /* to-scientific-string -- conversion to numeric string */
283 /* to-engineering-string -- conversion to numeric string */
284 /* */
285 /* decimal64ToString(d64, string); */
286 /* decimal64ToEngString(d64, string); */
287 /* */
288 /* d64 is the decimal64 format number to convert */
289 /* string is the string where the result will be laid out */
290 /* */
291 /* string must be at least 24 characters */
292 /* */
293 /* No error is possible, and no status can be set. */
294 /* ------------------------------------------------------------------ */
295 char * decimal64ToEngString(const decimal64 *d64, char *string){
296 decNumber dn; /* work */
297 decimal64ToNumber(d64, &dn);
298 decNumberToEngString(&dn, string);
299 return string;
300 } /* decimal64ToEngString */
301
302 char * decimal64ToString(const decimal64 *d64, char *string){
303 uInt msd; /* coefficient MSD */
304 Int exp; /* exponent top two bits or full */
305 uInt comb; /* combination field */
306 char *cstart; /* coefficient start */
307 char *c; /* output pointer in string */
308 const uInt *pu; /* work */
309 char *s, *t; /* .. (source, target) */
310 Int dpd; /* .. */
311 Int pre, e; /* .. */
312 const uByte *u; /* .. */
313
314 uInt sourar[2]; /* source 64-bit */
315 #define sourhi sourar[1] /* name the word with the sign */
316 #define sourlo sourar[0] /* and the lower word */
317
318 /* load source from storage; this is endian */
319 pu=(const uInt *)d64->bytes; /* overlay */
320 if (DECLITEND) {
321 sourlo=pu[0]; /* directly load the low int */
322 sourhi=pu[1]; /* then the high int */
323 }
324 else {
325 sourhi=pu[0]; /* directly load the high int */
326 sourlo=pu[1]; /* then the low int */
327 }
328
329 c=string; /* where result will go */
330 if (((Int)sourhi)<0) *c++='-'; /* handle sign */
331
332 comb=(sourhi>>26)&0x1f; /* combination field */
333 msd=COMBMSD[comb]; /* decode the combination field */
334 exp=COMBEXP[comb]; /* .. */
335
336 if (exp==3) {
337 if (msd==0) { /* infinity */
338 strcpy(c, "Inf");
339 strcpy(c+3, "inity");
340 return string; /* easy */
341 }
342 if (sourhi&0x02000000) *c++='s'; /* sNaN */
343 strcpy(c, "NaN"); /* complete word */
344 c+=3; /* step past */
345 if (sourlo==0 && (sourhi&0x0003ffff)==0) return string; /* zero payload */
346 /* otherwise drop through to add integer; set correct exp */
347 exp=0; msd=0; /* setup for following code */
348 }
349 else exp=(exp<<8)+((sourhi>>18)&0xff)-DECIMAL64_Bias;
350
351 /* convert 16 digits of significand to characters */
352 cstart=c; /* save start of coefficient */
353 if (msd) *c++='0'+(char)msd; /* non-zero most significant digit */
354
355 /* Now decode the declets. After extracting each one, it is */
356 /* decoded to binary and then to a 4-char sequence by table lookup; */
357 /* the 4-chars are a 1-char length (significant digits, except 000 */
358 /* has length 0). This allows us to left-align the first declet */
359 /* with non-zero content, then remaining ones are full 3-char */
360 /* length. We use fixed-length memcpys because variable-length */
361 /* causes a subroutine call in GCC. (These are length 4 for speed */
362 /* and are safe because the array has an extra terminator byte.) */
363 #define dpd2char u=&BIN2CHAR[DPD2BIN[dpd]*4]; \
364 if (c!=cstart) {memcpy(c, u+1, 4); c+=3;} \
365 else if (*u) {memcpy(c, u+4-*u, 4); c+=*u;}
366
367 dpd=(sourhi>>8)&0x3ff; /* declet 1 */
368 dpd2char;
369 dpd=((sourhi&0xff)<<2) | (sourlo>>30); /* declet 2 */
370 dpd2char;
371 dpd=(sourlo>>20)&0x3ff; /* declet 3 */
372 dpd2char;
373 dpd=(sourlo>>10)&0x3ff; /* declet 4 */
374 dpd2char;
375 dpd=(sourlo)&0x3ff; /* declet 5 */
376 dpd2char;
377
378 if (c==cstart) *c++='0'; /* all zeros -- make 0 */
379
380 if (exp==0) { /* integer or NaN case -- easy */
381 *c='\0'; /* terminate */
382 return string;
383 }
384
385 /* non-0 exponent */
386 e=0; /* assume no E */
387 pre=c-cstart+exp;
388 /* [here, pre-exp is the digits count (==1 for zero)] */
389 if (exp>0 || pre<-5) { /* need exponential form */
390 e=pre-1; /* calculate E value */
391 pre=1; /* assume one digit before '.' */
392 } /* exponential form */
393
394 /* modify the coefficient, adding 0s, '.', and E+nn as needed */
395 s=c-1; /* source (LSD) */
396 if (pre>0) { /* ddd.ddd (plain), perhaps with E */
397 char *dotat=cstart+pre;
398 if (dotat<c) { /* if embedded dot needed... */
399 t=c; /* target */
400 for (; s>=dotat; s--, t--) *t=*s; /* open the gap; leave t at gap */
401 *t='.'; /* insert the dot */
402 c++; /* length increased by one */
403 }
404
405 /* finally add the E-part, if needed; it will never be 0, and has */
406 /* a maximum length of 3 digits */
407 if (e!=0) {
408 *c++='E'; /* starts with E */
409 *c++='+'; /* assume positive */
410 if (e<0) {
411 *(c-1)='-'; /* oops, need '-' */
412 e=-e; /* uInt, please */
413 }
414 u=&BIN2CHAR[e*4]; /* -> length byte */
415 memcpy(c, u+4-*u, 4); /* copy fixed 4 characters [is safe] */
416 c+=*u; /* bump pointer appropriately */
417 }
418 *c='\0'; /* add terminator */
419 /*printf("res %s\n", string); */
420 return string;
421 } /* pre>0 */
422
423 /* -5<=pre<=0: here for plain 0.ddd or 0.000ddd forms (can never have E) */
424 t=c+1-pre;
425 *(t+1)='\0'; /* can add terminator now */
426 for (; s>=cstart; s--, t--) *t=*s; /* shift whole coefficient right */
427 c=cstart;
428 *c++='0'; /* always starts with 0. */
429 *c++='.';
430 for (; pre<0; pre++) *c++='0'; /* add any 0's after '.' */
431 /*printf("res %s\n", string); */
432 return string;
433 } /* decimal64ToString */
434
435 /* ------------------------------------------------------------------ */
436 /* to-number -- conversion from numeric string */
437 /* */
438 /* decimal64FromString(result, string, set); */
439 /* */
440 /* result is the decimal64 format number which gets the result of */
441 /* the conversion */
442 /* *string is the character string which should contain a valid */
443 /* number (which may be a special value) */
444 /* set is the context */
445 /* */
446 /* The context is supplied to this routine is used for error handling */
447 /* (setting of status and traps) and for the rounding mode, only. */
448 /* If an error occurs, the result will be a valid decimal64 NaN. */
449 /* ------------------------------------------------------------------ */
450 decimal64 * decimal64FromString(decimal64 *result, const char *string,
451 decContext *set) {
452 decContext dc; /* work */
453 decNumber dn; /* .. */
454
455 decContextDefault(&dc, DEC_INIT_DECIMAL64); /* no traps, please */
456 dc.round=set->round; /* use supplied rounding */
457
458 decNumberFromString(&dn, string, &dc); /* will round if needed */
459
460 decimal64FromNumber(result, &dn, &dc);
461 if (dc.status!=0) { /* something happened */
462 decContextSetStatus(set, dc.status); /* .. pass it on */
463 }
464 return result;
465 } /* decimal64FromString */
466
467 /* ------------------------------------------------------------------ */
468 /* decimal64IsCanonical -- test whether encoding is canonical */
469 /* d64 is the source decimal64 */
470 /* returns 1 if the encoding of d64 is canonical, 0 otherwise */
471 /* No error is possible. */
472 /* ------------------------------------------------------------------ */
473 uint32_t decimal64IsCanonical(const decimal64 *d64) {
474 decNumber dn; /* work */
475 decimal64 canon; /* .. */
476 decContext dc; /* .. */
477 decContextDefault(&dc, DEC_INIT_DECIMAL64);
478 decimal64ToNumber(d64, &dn);
479 decimal64FromNumber(&canon, &dn, &dc);/* canon will now be canonical */
480 return memcmp(d64, &canon, DECIMAL64_Bytes)==0;
481 } /* decimal64IsCanonical */
482
483 /* ------------------------------------------------------------------ */
484 /* decimal64Canonical -- copy an encoding, ensuring it is canonical */
485 /* d64 is the source decimal64 */
486 /* result is the target (may be the same decimal64) */
487 /* returns result */
488 /* No error is possible. */
489 /* ------------------------------------------------------------------ */
490 decimal64 * decimal64Canonical(decimal64 *result, const decimal64 *d64) {
491 decNumber dn; /* work */
492 decContext dc; /* .. */
493 decContextDefault(&dc, DEC_INIT_DECIMAL64);
494 decimal64ToNumber(d64, &dn);
495 decimal64FromNumber(result, &dn, &dc);/* result will now be canonical */
496 return result;
497 } /* decimal64Canonical */
498
499 #if DECTRACE || DECCHECK
500 /* Macros for accessing decimal64 fields. These assume the
501 argument is a reference (pointer) to the decimal64 structure,
502 and the decimal64 is in network byte order (big-endian) */
503 /* Get sign */
504 #define decimal64Sign(d) ((unsigned)(d)->bytes[0]>>7)
505
506 /* Get combination field */
507 #define decimal64Comb(d) (((d)->bytes[0] & 0x7c)>>2)
508
509 /* Get exponent continuation [does not remove bias] */
510 #define decimal64ExpCon(d) ((((d)->bytes[0] & 0x03)<<6) \
511 | ((unsigned)(d)->bytes[1]>>2))
512
513 /* Set sign [this assumes sign previously 0] */
514 #define decimal64SetSign(d, b) { \
515 (d)->bytes[0]|=((unsigned)(b)<<7);}
516
517 /* Set exponent continuation [does not apply bias] */
518 /* This assumes range has been checked and exponent previously 0; */
519 /* type of exponent must be unsigned */
520 #define decimal64SetExpCon(d, e) { \
521 (d)->bytes[0]|=(uint8_t)((e)>>6); \
522 (d)->bytes[1]|=(uint8_t)(((e)&0x3F)<<2);}
523
524 /* ------------------------------------------------------------------ */
525 /* decimal64Show -- display a decimal64 in hexadecimal [debug aid] */
526 /* d64 -- the number to show */
527 /* ------------------------------------------------------------------ */
528 /* Also shows sign/cob/expconfields extracted */
529 void decimal64Show(const decimal64 *d64) {
530 char buf[DECIMAL64_Bytes*2+1];
531 Int i, j=0;
532
533 if (DECLITEND) {
534 for (i=0; i<DECIMAL64_Bytes; i++, j+=2) {
535 sprintf(&buf[j], "%02x", d64->bytes[7-i]);
536 }
537 printf(" D64> %s [S:%d Cb:%02x Ec:%02x] LittleEndian\n", buf,
538 d64->bytes[7]>>7, (d64->bytes[7]>>2)&0x1f,
539 ((d64->bytes[7]&0x3)<<6)| (d64->bytes[6]>>2));
540 }
541 else { /* big-endian */
542 for (i=0; i<DECIMAL64_Bytes; i++, j+=2) {
543 sprintf(&buf[j], "%02x", d64->bytes[i]);
544 }
545 printf(" D64> %s [S:%d Cb:%02x Ec:%02x] BigEndian\n", buf,
546 decimal64Sign(d64), decimal64Comb(d64), decimal64ExpCon(d64));
547 }
548 } /* decimal64Show */
549 #endif
550
551 /* ================================================================== */
552 /* Shared utility routines and tables */
553 /* ================================================================== */
554 /* define and include the conversion tables to use for shared code */
555 #if DECDPUN==3
556 #define DEC_DPD2BIN 1
557 #else
558 #define DEC_DPD2BCD 1
559 #endif
560 #include "libdecnumber/decDPD.h"
561
562 /* The maximum number of decNumberUnits needed for a working copy of */
563 /* the units array is the ceiling of digits/DECDPUN, where digits is */
564 /* the maximum number of digits in any of the formats for which this */
565 /* is used. decimal128.h must not be included in this module, so, as */
566 /* a very special case, that number is defined as a literal here. */
567 #define DECMAX754 34
568 #define DECMAXUNITS ((DECMAX754+DECDPUN-1)/DECDPUN)
569
570 /* ------------------------------------------------------------------ */
571 /* Combination field lookup tables (uInts to save measurable work) */
572 /* */
573 /* COMBEXP - 2-bit most-significant-bits of exponent */
574 /* [11 if an Infinity or NaN] */
575 /* COMBMSD - 4-bit most-significant-digit */
576 /* [0=Infinity, 1=NaN if COMBEXP=11] */
577 /* */
578 /* Both are indexed by the 5-bit combination field (0-31) */
579 /* ------------------------------------------------------------------ */
580 const uInt COMBEXP[32]={0, 0, 0, 0, 0, 0, 0, 0,
581 1, 1, 1, 1, 1, 1, 1, 1,
582 2, 2, 2, 2, 2, 2, 2, 2,
583 0, 0, 1, 1, 2, 2, 3, 3};
584 const uInt COMBMSD[32]={0, 1, 2, 3, 4, 5, 6, 7,
585 0, 1, 2, 3, 4, 5, 6, 7,
586 0, 1, 2, 3, 4, 5, 6, 7,
587 8, 9, 8, 9, 8, 9, 0, 1};
588
589 /* ------------------------------------------------------------------ */
590 /* decDigitsToDPD -- pack coefficient into DPD form */
591 /* */
592 /* dn is the source number (assumed valid, max DECMAX754 digits) */
593 /* targ is 1, 2, or 4-element uInt array, which the caller must */
594 /* have cleared to zeros */
595 /* shift is the number of 0 digits to add on the right (normally 0) */
596 /* */
597 /* The coefficient must be known small enough to fit. The full */
598 /* coefficient is copied, including the leading 'odd' digit. This */
599 /* digit is retrieved and packed into the combination field by the */
600 /* caller. */
601 /* */
602 /* The target uInts are altered only as necessary to receive the */
603 /* digits of the decNumber. When more than one uInt is needed, they */
604 /* are filled from left to right (that is, the uInt at offset 0 will */
605 /* end up with the least-significant digits). */
606 /* */
607 /* shift is used for 'fold-down' padding. */
608 /* */
609 /* No error is possible. */
610 /* ------------------------------------------------------------------ */
611 #if DECDPUN<=4
612 /* Constant multipliers for divide-by-power-of five using reciprocal */
613 /* multiply, after removing powers of 2 by shifting, and final shift */
614 /* of 17 [we only need up to **4] */
615 static const uInt multies[]={131073, 26215, 5243, 1049, 210};
616 /* QUOT10 -- macro to return the quotient of unit u divided by 10**n */
617 #define QUOT10(u, n) ((((uInt)(u)>>(n))*multies[n])>>17)
618 #endif
619 void decDigitsToDPD(const decNumber *dn, uInt *targ, Int shift) {
620 Int cut; /* work */
621 Int n; /* output bunch counter */
622 Int digits=dn->digits; /* digit countdown */
623 uInt dpd; /* densely packed decimal value */
624 uInt bin; /* binary value 0-999 */
625 uInt *uout=targ; /* -> current output uInt */
626 uInt uoff=0; /* -> current output offset [from right] */
627 const Unit *inu=dn->lsu; /* -> current input unit */
628 Unit uar[DECMAXUNITS]; /* working copy of units, iff shifted */
629 #if DECDPUN!=3 /* not fast path */
630 Unit in; /* current unit */
631 #endif
632
633 if (shift!=0) { /* shift towards most significant required */
634 /* shift the units array to the left by pad digits and copy */
635 /* [this code is a special case of decShiftToMost, which could */
636 /* be used instead if exposed and the array were copied first] */
637 const Unit *source; /* .. */
638 Unit *target, *first; /* .. */
639 uInt next=0; /* work */
640
641 source=dn->lsu+D2U(digits)-1; /* where msu comes from */
642 target=uar+D2U(digits)-1+D2U(shift);/* where upper part of first cut goes */
643 cut=DECDPUN-MSUDIGITS(shift); /* where to slice */
644 if (cut==0) { /* unit-boundary case */
645 for (; source>=dn->lsu; source--, target--) *target=*source;
646 }
647 else {
648 first=uar+D2U(digits+shift)-1; /* where msu will end up */
649 for (; source>=dn->lsu; source--, target--) {
650 /* split the source Unit and accumulate remainder for next */
651 #if DECDPUN<=4
652 uInt quot=QUOT10(*source, cut);
653 uInt rem=*source-quot*DECPOWERS[cut];
654 next+=quot;
655 #else
656 uInt rem=*source%DECPOWERS[cut];
657 next+=*source/DECPOWERS[cut];
658 #endif
659 if (target<=first) *target=(Unit)next; /* write to target iff valid */
660 next=rem*DECPOWERS[DECDPUN-cut]; /* save remainder for next Unit */
661 }
662 } /* shift-move */
663 /* propagate remainder to one below and clear the rest */
664 for (; target>=uar; target--) {
665 *target=(Unit)next;
666 next=0;
667 }
668 digits+=shift; /* add count (shift) of zeros added */
669 inu=uar; /* use units in working array */
670 }
671
672 /* now densely pack the coefficient into DPD declets */
673
674 #if DECDPUN!=3 /* not fast path */
675 in=*inu; /* current unit */
676 cut=0; /* at lowest digit */
677 bin=0; /* [keep compiler quiet] */
678 #endif
679
680 for(n=0; digits>0; n++) { /* each output bunch */
681 #if DECDPUN==3 /* fast path, 3-at-a-time */
682 bin=*inu; /* 3 digits ready for convert */
683 digits-=3; /* [may go negative] */
684 inu++; /* may need another */
685
686 #else /* must collect digit-by-digit */
687 Unit dig; /* current digit */
688 Int j; /* digit-in-declet count */
689 for (j=0; j<3; j++) {
690 #if DECDPUN<=4
691 Unit temp=(Unit)((uInt)(in*6554)>>16);
692 dig=(Unit)(in-X10(temp));
693 in=temp;
694 #else
695 dig=in%10;
696 in=in/10;
697 #endif
698 if (j==0) bin=dig;
699 else if (j==1) bin+=X10(dig);
700 else /* j==2 */ bin+=X100(dig);
701 digits--;
702 if (digits==0) break; /* [also protects *inu below] */
703 cut++;
704 if (cut==DECDPUN) {inu++; in=*inu; cut=0;}
705 }
706 #endif
707 /* here there are 3 digits in bin, or have used all input digits */
708
709 dpd=BIN2DPD[bin];
710
711 /* write declet to uInt array */
712 *uout|=dpd<<uoff;
713 uoff+=10;
714 if (uoff<32) continue; /* no uInt boundary cross */
715 uout++;
716 uoff-=32;
717 *uout|=dpd>>(10-uoff); /* collect top bits */
718 } /* n declets */
719 return;
720 } /* decDigitsToDPD */
721
722 /* ------------------------------------------------------------------ */
723 /* decDigitsFromDPD -- unpack a format's coefficient */
724 /* */
725 /* dn is the target number, with 7, 16, or 34-digit space. */
726 /* sour is a 1, 2, or 4-element uInt array containing only declets */
727 /* declets is the number of (right-aligned) declets in sour to */
728 /* be processed. This may be 1 more than the obvious number in */
729 /* a format, as any top digit is prefixed to the coefficient */
730 /* continuation field. It also may be as small as 1, as the */
731 /* caller may pre-process leading zero declets. */
732 /* */
733 /* When doing the 'extra declet' case care is taken to avoid writing */
734 /* extra digits when there are leading zeros, as these could overflow */
735 /* the units array when DECDPUN is not 3. */
736 /* */
737 /* The target uInts are used only as necessary to process declets */
738 /* declets into the decNumber. When more than one uInt is needed, */
739 /* they are used from left to right (that is, the uInt at offset 0 */
740 /* provides the least-significant digits). */
741 /* */
742 /* dn->digits is set, but not the sign or exponent. */
743 /* No error is possible [the redundant 888 codes are allowed]. */
744 /* ------------------------------------------------------------------ */
745 void decDigitsFromDPD(decNumber *dn, const uInt *sour, Int declets) {
746
747 uInt dpd; /* collector for 10 bits */
748 Int n; /* counter */
749 Unit *uout=dn->lsu; /* -> current output unit */
750 Unit *last=uout; /* will be unit containing msd */
751 const uInt *uin=sour; /* -> current input uInt */
752 uInt uoff=0; /* -> current input offset [from right] */
753
754 #if DECDPUN!=3
755 uInt bcd; /* BCD result */
756 uInt nibble; /* work */
757 Unit out=0; /* accumulator */
758 Int cut=0; /* power of ten in current unit */
759 #endif
760 #if DECDPUN>4
761 uInt const *pow; /* work */
762 #endif
763
764 /* Expand the densely-packed integer, right to left */
765 for (n=declets-1; n>=0; n--) { /* count down declets of 10 bits */
766 dpd=*uin>>uoff;
767 uoff+=10;
768 if (uoff>32) { /* crossed uInt boundary */
769 uin++;
770 uoff-=32;
771 dpd|=*uin<<(10-uoff); /* get waiting bits */
772 }
773 dpd&=0x3ff; /* clear uninteresting bits */
774
775 #if DECDPUN==3
776 if (dpd==0) *uout=0;
777 else {
778 *uout=DPD2BIN[dpd]; /* convert 10 bits to binary 0-999 */
779 last=uout; /* record most significant unit */
780 }
781 uout++;
782 } /* n */
783
784 #else /* DECDPUN!=3 */
785 if (dpd==0) { /* fastpath [e.g., leading zeros] */
786 /* write out three 0 digits (nibbles); out may have digit(s) */
787 cut++;
788 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
789 if (n==0) break; /* [as below, works even if MSD=0] */
790 cut++;
791 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
792 cut++;
793 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
794 continue;
795 }
796
797 bcd=DPD2BCD[dpd]; /* convert 10 bits to 12 bits BCD */
798
799 /* now accumulate the 3 BCD nibbles into units */
800 nibble=bcd & 0x00f;
801 if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
802 cut++;
803 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
804 bcd>>=4;
805
806 /* if this is the last declet and the remaining nibbles in bcd */
807 /* are 00 then process no more nibbles, because this could be */
808 /* the 'odd' MSD declet and writing any more Units would then */
809 /* overflow the unit array */
810 if (n==0 && !bcd) break;
811
812 nibble=bcd & 0x00f;
813 if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
814 cut++;
815 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
816 bcd>>=4;
817
818 nibble=bcd & 0x00f;
819 if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
820 cut++;
821 if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
822 } /* n */
823 if (cut!=0) { /* some more left over */
824 *uout=out; /* write out final unit */
825 if (out) last=uout; /* and note if non-zero */
826 }
827 #endif
828
829 /* here, last points to the most significant unit with digits; */
830 /* inspect it to get the final digits count -- this is essentially */
831 /* the same code as decGetDigits in decNumber.c */
832 dn->digits=(last-dn->lsu)*DECDPUN+1; /* floor of digits, plus */
833 /* must be at least 1 digit */
834 #if DECDPUN>1
835 if (*last<10) return; /* common odd digit or 0 */
836 dn->digits++; /* must be 2 at least */
837 #if DECDPUN>2
838 if (*last<100) return; /* 10-99 */
839 dn->digits++; /* must be 3 at least */
840 #if DECDPUN>3
841 if (*last<1000) return; /* 100-999 */
842 dn->digits++; /* must be 4 at least */
843 #if DECDPUN>4
844 for (pow=&DECPOWERS[4]; *last>=*pow; pow++) dn->digits++;
845 #endif
846 #endif
847 #endif
848 #endif
849 return;
850 } /*decDigitsFromDPD */
AR7 emulation for QEMU