1/* Decimal 32-bit format module for the decNumber C Library. 2 Copyright (C) 2005-2015 Free Software Foundation, Inc. 3 Contributed by IBM Corporation. Author Mike Cowlishaw. 4 5 This file is part of GCC. 6 7 GCC is free software; you can redistribute it and/or modify it under 8 the terms of the GNU General Public License as published by the Free 9 Software Foundation; either version 3, or (at your option) any later 10 version. 11 12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 13 WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 for more details. 16 17Under Section 7 of GPL version 3, you are granted additional 18permissions described in the GCC Runtime Library Exception, version 193.1, as published by the Free Software Foundation. 20 21You should have received a copy of the GNU General Public License and 22a copy of the GCC Runtime Library Exception along with this program; 23see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24<http://www.gnu.org/licenses/>. */ 25 26/* ------------------------------------------------------------------ */ 27/* Decimal 32-bit format module */ 28/* ------------------------------------------------------------------ */ 29/* This module comprises the routines for decimal32 format numbers. */ 30/* Conversions are supplied to and from decNumber and String. */ 31/* */ 32/* This is used when decNumber provides operations, either for all */ 33/* operations or as a proxy between decNumber and decSingle. */ 34/* */ 35/* Error handling is the same as decNumber (qv.). */ 36/* ------------------------------------------------------------------ */ 37#include <string.h> /* [for memset/memcpy] */ 38#include <stdio.h> /* [for printf] */ 39 40#include "dconfig.h" /* GCC definitions */ 41#define DECNUMDIGITS 7 /* make decNumbers with space for 7 */ 42#include "decNumber.h" /* base number library */ 43#include "decNumberLocal.h" /* decNumber local types, etc. */ 44#include "decimal32.h" /* our primary include */ 45 46/* Utility tables and routines [in decimal64.c] */ 47extern const uInt COMBEXP[32], COMBMSD[32]; 48extern const uShort DPD2BIN[1024]; 49extern const uShort BIN2DPD[1000]; 50extern const uByte BIN2CHAR[4001]; 51 52extern void decDigitsToDPD(const decNumber *, uInt *, Int); 53extern void decDigitsFromDPD(decNumber *, const uInt *, Int); 54 55#if DECTRACE || DECCHECK 56void decimal32Show(const decimal32 *); /* for debug */ 57extern void decNumberShow(const decNumber *); /* .. */ 58#endif 59 60/* Useful macro */ 61/* Clear a structure (e.g., a decNumber) */ 62#define DEC_clear(d) memset(d, 0, sizeof(*d)) 63 64/* ------------------------------------------------------------------ */ 65/* decimal32FromNumber -- convert decNumber to decimal32 */ 66/* */ 67/* ds is the target decimal32 */ 68/* dn is the source number (assumed valid) */ 69/* set is the context, used only for reporting errors */ 70/* */ 71/* The set argument is used only for status reporting and for the */ 72/* rounding mode (used if the coefficient is more than DECIMAL32_Pmax */ 73/* digits or an overflow is detected). If the exponent is out of the */ 74/* valid range then Overflow or Underflow will be raised. */ 75/* After Underflow a subnormal result is possible. */ 76/* */ 77/* DEC_Clamped is set if the number has to be 'folded down' to fit, */ 78/* by reducing its exponent and multiplying the coefficient by a */ 79/* power of ten, or if the exponent on a zero had to be clamped. */ 80/* ------------------------------------------------------------------ */ 81decimal32 * decimal32FromNumber(decimal32 *d32, const decNumber *dn, 82 decContext *set) { 83 uInt status=0; /* status accumulator */ 84 Int ae; /* adjusted exponent */ 85 decNumber dw; /* work */ 86 decContext dc; /* .. */ 87 uInt comb, exp; /* .. */ 88 uInt uiwork; /* for macros */ 89 uInt targ=0; /* target 32-bit */ 90 91 /* If the number has too many digits, or the exponent could be */ 92 /* out of range then reduce the number under the appropriate */ 93 /* constraints. This could push the number to Infinity or zero, */ 94 /* so this check and rounding must be done before generating the */ 95 /* decimal32] */ 96 ae=dn->exponent+dn->digits-1; /* [0 if special] */ 97 if (dn->digits>DECIMAL32_Pmax /* too many digits */ 98 || ae>DECIMAL32_Emax /* likely overflow */ 99 || ae<DECIMAL32_Emin) { /* likely underflow */ 100 decContextDefault(&dc, DEC_INIT_DECIMAL32); /* [no traps] */ 101 dc.round=set->round; /* use supplied rounding */ 102 decNumberPlus(&dw, dn, &dc); /* (round and check) */ 103 /* [this changes -0 to 0, so enforce the sign...] */ 104 dw.bits|=dn->bits&DECNEG; 105 status=dc.status; /* save status */ 106 dn=&dw; /* use the work number */ 107 } /* maybe out of range */ 108 109 if (dn->bits&DECSPECIAL) { /* a special value */ 110 if (dn->bits&DECINF) targ=DECIMAL_Inf<<24; 111 else { /* sNaN or qNaN */ 112 if ((*dn->lsu!=0 || dn->digits>1) /* non-zero coefficient */ 113 && (dn->digits<DECIMAL32_Pmax)) { /* coefficient fits */ 114 decDigitsToDPD(dn, &targ, 0); 115 } 116 if (dn->bits&DECNAN) targ|=DECIMAL_NaN<<24; 117 else targ|=DECIMAL_sNaN<<24; 118 } /* a NaN */ 119 } /* special */ 120 121 else { /* is finite */ 122 if (decNumberIsZero(dn)) { /* is a zero */ 123 /* set and clamp exponent */ 124 if (dn->exponent<-DECIMAL32_Bias) { 125 exp=0; /* low clamp */ 126 status|=DEC_Clamped; 127 } 128 else { 129 exp=dn->exponent+DECIMAL32_Bias; /* bias exponent */ 130 if (exp>DECIMAL32_Ehigh) { /* top clamp */ 131 exp=DECIMAL32_Ehigh; 132 status|=DEC_Clamped; 133 } 134 } 135 comb=(exp>>3) & 0x18; /* msd=0, exp top 2 bits .. */ 136 } 137 else { /* non-zero finite number */ 138 uInt msd; /* work */ 139 Int pad=0; /* coefficient pad digits */ 140 141 /* the dn is known to fit, but it may need to be padded */ 142 exp=(uInt)(dn->exponent+DECIMAL32_Bias); /* bias exponent */ 143 if (exp>DECIMAL32_Ehigh) { /* fold-down case */ 144 pad=exp-DECIMAL32_Ehigh; 145 exp=DECIMAL32_Ehigh; /* [to maximum] */ 146 status|=DEC_Clamped; 147 } 148 149 /* fastpath common case */ 150 if (DECDPUN==3 && pad==0) { 151 targ=BIN2DPD[dn->lsu[0]]; 152 if (dn->digits>3) targ|=(uInt)(BIN2DPD[dn->lsu[1]])<<10; 153 msd=(dn->digits==7 ? dn->lsu[2] : 0); 154 } 155 else { /* general case */ 156 decDigitsToDPD(dn, &targ, pad); 157 /* save and clear the top digit */ 158 msd=targ>>20; 159 targ&=0x000fffff; 160 } 161 162 /* create the combination field */ 163 if (msd>=8) comb=0x18 | ((exp>>5) & 0x06) | (msd & 0x01); 164 else comb=((exp>>3) & 0x18) | msd; 165 } 166 targ|=comb<<26; /* add combination field .. */ 167 targ|=(exp&0x3f)<<20; /* .. and exponent continuation */ 168 } /* finite */ 169 170 if (dn->bits&DECNEG) targ|=0x80000000; /* add sign bit */ 171 172 /* now write to storage; this is endian */ 173 UBFROMUI(d32->bytes, targ); /* directly store the int */ 174 175 if (status!=0) decContextSetStatus(set, status); /* pass on status */ 176 /* decimal32Show(d32); */ 177 return d32; 178 } /* decimal32FromNumber */ 179 180/* ------------------------------------------------------------------ */ 181/* decimal32ToNumber -- convert decimal32 to decNumber */ 182/* d32 is the source decimal32 */ 183/* dn is the target number, with appropriate space */ 184/* No error is possible. */ 185/* ------------------------------------------------------------------ */ 186decNumber * decimal32ToNumber(const decimal32 *d32, decNumber *dn) { 187 uInt msd; /* coefficient MSD */ 188 uInt exp; /* exponent top two bits */ 189 uInt comb; /* combination field */ 190 uInt sour; /* source 32-bit */ 191 uInt uiwork; /* for macros */ 192 193 /* load source from storage; this is endian */ 194 sour=UBTOUI(d32->bytes); /* directly load the int */ 195 196 comb=(sour>>26)&0x1f; /* combination field */ 197 198 decNumberZero(dn); /* clean number */ 199 if (sour&0x80000000) dn->bits=DECNEG; /* set sign if negative */ 200 201 msd=COMBMSD[comb]; /* decode the combination field */ 202 exp=COMBEXP[comb]; /* .. */ 203 204 if (exp==3) { /* is a special */ 205 if (msd==0) { 206 dn->bits|=DECINF; 207 return dn; /* no coefficient needed */ 208 } 209 else if (sour&0x02000000) dn->bits|=DECSNAN; 210 else dn->bits|=DECNAN; 211 msd=0; /* no top digit */ 212 } 213 else { /* is a finite number */ 214 dn->exponent=(exp<<6)+((sour>>20)&0x3f)-DECIMAL32_Bias; /* unbiased */ 215 } 216 217 /* get the coefficient */ 218 sour&=0x000fffff; /* clean coefficient continuation */ 219 if (msd) { /* non-zero msd */ 220 sour|=msd<<20; /* prefix to coefficient */ 221 decDigitsFromDPD(dn, &sour, 3); /* process 3 declets */ 222 return dn; 223 } 224 /* msd=0 */ 225 if (!sour) return dn; /* easy: coefficient is 0 */ 226 if (sour&0x000ffc00) /* need 2 declets? */ 227 decDigitsFromDPD(dn, &sour, 2); /* process 2 declets */ 228 else 229 decDigitsFromDPD(dn, &sour, 1); /* process 1 declet */ 230 return dn; 231 } /* decimal32ToNumber */ 232 233/* ------------------------------------------------------------------ */ 234/* to-scientific-string -- conversion to numeric string */ 235/* to-engineering-string -- conversion to numeric string */ 236/* */ 237/* decimal32ToString(d32, string); */ 238/* decimal32ToEngString(d32, string); */ 239/* */ 240/* d32 is the decimal32 format number to convert */ 241/* string is the string where the result will be laid out */ 242/* */ 243/* string must be at least 24 characters */ 244/* */ 245/* No error is possible, and no status can be set. */ 246/* ------------------------------------------------------------------ */ 247char * decimal32ToEngString(const decimal32 *d32, char *string){ 248 decNumber dn; /* work */ 249 decimal32ToNumber(d32, &dn); 250 decNumberToEngString(&dn, string); 251 return string; 252 } /* decimal32ToEngString */ 253 254char * decimal32ToString(const decimal32 *d32, char *string){ 255 uInt msd; /* coefficient MSD */ 256 Int exp; /* exponent top two bits or full */ 257 uInt comb; /* combination field */ 258 char *cstart; /* coefficient start */ 259 char *c; /* output pointer in string */ 260 const uByte *u; /* work */ 261 char *s, *t; /* .. (source, target) */ 262 Int dpd; /* .. */ 263 Int pre, e; /* .. */ 264 uInt uiwork; /* for macros */ 265 uInt sour; /* source 32-bit */ 266 267 /* load source from storage; this is endian */ 268 sour=UBTOUI(d32->bytes); /* directly load the int */ 269 270 c=string; /* where result will go */ 271 if (((Int)sour)<0) *c++='-'; /* handle sign */ 272 273 comb=(sour>>26)&0x1f; /* combination field */ 274 msd=COMBMSD[comb]; /* decode the combination field */ 275 exp=COMBEXP[comb]; /* .. */ 276 277 if (exp==3) { 278 if (msd==0) { /* infinity */ 279 strcpy(c, "Inf"); 280 strcpy(c+3, "inity"); 281 return string; /* easy */ 282 } 283 if (sour&0x02000000) *c++='s'; /* sNaN */ 284 strcpy(c, "NaN"); /* complete word */ 285 c+=3; /* step past */ 286 if ((sour&0x000fffff)==0) return string; /* zero payload */ 287 /* otherwise drop through to add integer; set correct exp */ 288 exp=0; msd=0; /* setup for following code */ 289 } 290 else exp=(exp<<6)+((sour>>20)&0x3f)-DECIMAL32_Bias; /* unbiased */ 291 292 /* convert 7 digits of significand to characters */ 293 cstart=c; /* save start of coefficient */ 294 if (msd) *c++='0'+(char)msd; /* non-zero most significant digit */ 295 296 /* Now decode the declets. After extracting each one, it is */ 297 /* decoded to binary and then to a 4-char sequence by table lookup; */ 298 /* the 4-chars are a 1-char length (significant digits, except 000 */ 299 /* has length 0). This allows us to left-align the first declet */ 300 /* with non-zero content, then remaining ones are full 3-char */ 301 /* length. We use fixed-length memcpys because variable-length */ 302 /* causes a subroutine call in GCC. (These are length 4 for speed */ 303 /* and are safe because the array has an extra terminator byte.) */ 304 #define dpd2char u=&BIN2CHAR[DPD2BIN[dpd]*4]; \ 305 if (c!=cstart) {memcpy(c, u+1, 4); c+=3;} \ 306 else if (*u) {memcpy(c, u+4-*u, 4); c+=*u;} 307 308 dpd=(sour>>10)&0x3ff; /* declet 1 */ 309 dpd2char; 310 dpd=(sour)&0x3ff; /* declet 2 */ 311 dpd2char; 312 313 if (c==cstart) *c++='0'; /* all zeros -- make 0 */ 314 315 if (exp==0) { /* integer or NaN case -- easy */ 316 *c='\0'; /* terminate */ 317 return string; 318 } 319 320 /* non-0 exponent */ 321 e=0; /* assume no E */ 322 pre=c-cstart+exp; 323 /* [here, pre-exp is the digits count (==1 for zero)] */ 324 if (exp>0 || pre<-5) { /* need exponential form */ 325 e=pre-1; /* calculate E value */ 326 pre=1; /* assume one digit before '.' */ 327 } /* exponential form */ 328 329 /* modify the coefficient, adding 0s, '.', and E+nn as needed */ 330 s=c-1; /* source (LSD) */ 331 if (pre>0) { /* ddd.ddd (plain), perhaps with E */ 332 char *dotat=cstart+pre; 333 if (dotat<c) { /* if embedded dot needed... */ 334 t=c; /* target */ 335 for (; s>=dotat; s--, t--) *t=*s; /* open the gap; leave t at gap */ 336 *t='.'; /* insert the dot */ 337 c++; /* length increased by one */ 338 } 339 340 /* finally add the E-part, if needed; it will never be 0, and has */ 341 /* a maximum length of 3 digits (E-101 case) */ 342 if (e!=0) { 343 *c++='E'; /* starts with E */ 344 *c++='+'; /* assume positive */ 345 if (e<0) { 346 *(c-1)='-'; /* oops, need '-' */ 347 e=-e; /* uInt, please */ 348 } 349 u=&BIN2CHAR[e*4]; /* -> length byte */ 350 memcpy(c, u+4-*u, 4); /* copy fixed 4 characters [is safe] */ 351 c+=*u; /* bump pointer appropriately */ 352 } 353 *c='\0'; /* add terminator */ 354 /*printf("res %s\n", string); */ 355 return string; 356 } /* pre>0 */ 357 358 /* -5<=pre<=0: here for plain 0.ddd or 0.000ddd forms (can never have E) */ 359 t=c+1-pre; 360 *(t+1)='\0'; /* can add terminator now */ 361 for (; s>=cstart; s--, t--) *t=*s; /* shift whole coefficient right */ 362 c=cstart; 363 *c++='0'; /* always starts with 0. */ 364 *c++='.'; 365 for (; pre<0; pre++) *c++='0'; /* add any 0's after '.' */ 366 /*printf("res %s\n", string); */ 367 return string; 368 } /* decimal32ToString */ 369 370/* ------------------------------------------------------------------ */ 371/* to-number -- conversion from numeric string */ 372/* */ 373/* decimal32FromString(result, string, set); */ 374/* */ 375/* result is the decimal32 format number which gets the result of */ 376/* the conversion */ 377/* *string is the character string which should contain a valid */ 378/* number (which may be a special value) */ 379/* set is the context */ 380/* */ 381/* The context is supplied to this routine is used for error handling */ 382/* (setting of status and traps) and for the rounding mode, only. */ 383/* If an error occurs, the result will be a valid decimal32 NaN. */ 384/* ------------------------------------------------------------------ */ 385decimal32 * decimal32FromString(decimal32 *result, const char *string, 386 decContext *set) { 387 decContext dc; /* work */ 388 decNumber dn; /* .. */ 389 390 decContextDefault(&dc, DEC_INIT_DECIMAL32); /* no traps, please */ 391 dc.round=set->round; /* use supplied rounding */ 392 393 decNumberFromString(&dn, string, &dc); /* will round if needed */ 394 decimal32FromNumber(result, &dn, &dc); 395 if (dc.status!=0) { /* something happened */ 396 decContextSetStatus(set, dc.status); /* .. pass it on */ 397 } 398 return result; 399 } /* decimal32FromString */ 400 401/* ------------------------------------------------------------------ */ 402/* decimal32IsCanonical -- test whether encoding is canonical */ 403/* d32 is the source decimal32 */ 404/* returns 1 if the encoding of d32 is canonical, 0 otherwise */ 405/* No error is possible. */ 406/* ------------------------------------------------------------------ */ 407uInt decimal32IsCanonical(const decimal32 *d32) { 408 decNumber dn; /* work */ 409 decimal32 canon; /* .. */ 410 decContext dc; /* .. */ 411 decContextDefault(&dc, DEC_INIT_DECIMAL32); 412 decimal32ToNumber(d32, &dn); 413 decimal32FromNumber(&canon, &dn, &dc);/* canon will now be canonical */ 414 return memcmp(d32, &canon, DECIMAL32_Bytes)==0; 415 } /* decimal32IsCanonical */ 416 417/* ------------------------------------------------------------------ */ 418/* decimal32Canonical -- copy an encoding, ensuring it is canonical */ 419/* d32 is the source decimal32 */ 420/* result is the target (may be the same decimal32) */ 421/* returns result */ 422/* No error is possible. */ 423/* ------------------------------------------------------------------ */ 424decimal32 * decimal32Canonical(decimal32 *result, const decimal32 *d32) { 425 decNumber dn; /* work */ 426 decContext dc; /* .. */ 427 decContextDefault(&dc, DEC_INIT_DECIMAL32); 428 decimal32ToNumber(d32, &dn); 429 decimal32FromNumber(result, &dn, &dc);/* result will now be canonical */ 430 return result; 431 } /* decimal32Canonical */ 432 433#if DECTRACE || DECCHECK 434/* Macros for accessing decimal32 fields. These assume the argument 435 is a reference (pointer) to the decimal32 structure, and the 436 decimal32 is in network byte order (big-endian) */ 437/* Get sign */ 438#define decimal32Sign(d) ((unsigned)(d)->bytes[0]>>7) 439 440/* Get combination field */ 441#define decimal32Comb(d) (((d)->bytes[0] & 0x7c)>>2) 442 443/* Get exponent continuation [does not remove bias] */ 444#define decimal32ExpCon(d) ((((d)->bytes[0] & 0x03)<<4) \ 445 | ((unsigned)(d)->bytes[1]>>4)) 446 447/* Set sign [this assumes sign previously 0] */ 448#define decimal32SetSign(d, b) { \ 449 (d)->bytes[0]|=((unsigned)(b)<<7);} 450 451/* Set exponent continuation [does not apply bias] */ 452/* This assumes range has been checked and exponent previously 0; */ 453/* type of exponent must be unsigned */ 454#define decimal32SetExpCon(d, e) { \ 455 (d)->bytes[0]|=(uByte)((e)>>4); \ 456 (d)->bytes[1]|=(uByte)(((e)&0x0F)<<4);} 457 458/* ------------------------------------------------------------------ */ 459/* decimal32Show -- display a decimal32 in hexadecimal [debug aid] */ 460/* d32 -- the number to show */ 461/* ------------------------------------------------------------------ */ 462/* Also shows sign/cob/expconfields extracted - valid bigendian only */ 463void decimal32Show(const decimal32 *d32) { 464 char buf[DECIMAL32_Bytes*2+1]; 465 Int i, j=0; 466 467 if (DECLITEND) { 468 for (i=0; i<DECIMAL32_Bytes; i++, j+=2) { 469 sprintf(&buf[j], "%02x", d32->bytes[3-i]); 470 } 471 printf(" D32> %s [S:%d Cb:%02x Ec:%02x] LittleEndian\n", buf, 472 d32->bytes[3]>>7, (d32->bytes[3]>>2)&0x1f, 473 ((d32->bytes[3]&0x3)<<4)| (d32->bytes[2]>>4)); 474 } 475 else { 476 for (i=0; i<DECIMAL32_Bytes; i++, j+=2) { 477 sprintf(&buf[j], "%02x", d32->bytes[i]); 478 } 479 printf(" D32> %s [S:%d Cb:%02x Ec:%02x] BigEndian\n", buf, 480 decimal32Sign(d32), decimal32Comb(d32), decimal32ExpCon(d32)); 481 } 482 } /* decimal32Show */ 483#endif 484