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