| 1 | /* Decimal context module for the decNumber C Library. |
| 2 | Copyright (C) 2005, 2007, 2009 Free Software Foundation, Inc. |
| 3 | Contributed by IBM Corporation. Author Mike Cowlishaw. |
| 4 | |
| 5 | This file is part of GCC. |
| 6 | |
| 7 | GCC is free software; you can redistribute it and/or modify it under |
| 8 | the terms of the GNU General Public License as published by the Free |
| 9 | Software Foundation; either version 3, or (at your option) any later |
| 10 | version. |
| 11 | |
| 12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| 13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 15 | for more details. |
| 16 | |
| 17 | Under Section 7 of GPL version 3, you are granted additional |
| 18 | permissions described in the GCC Runtime Library Exception, version |
| 19 | 3.1, as published by the Free Software Foundation. |
| 20 | |
| 21 | You should have received a copy of the GNU General Public License and |
| 22 | a copy of the GCC Runtime Library Exception along with this program; |
| 23 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| 24 | <http://www.gnu.org/licenses/>. */ |
| 25 | |
| 26 | /* ------------------------------------------------------------------ */ |
| 27 | /* Decimal Context module */ |
| 28 | /* ------------------------------------------------------------------ */ |
| 29 | /* This module comprises the routines for handling arithmetic */ |
| 30 | /* context structures. */ |
| 31 | /* ------------------------------------------------------------------ */ |
| 32 | |
| 33 | #include <string.h> /* for strcmp */ |
| 34 | #ifdef DECCHECK |
| 35 | #include <stdio.h> /* for printf if DECCHECK */ |
| 36 | #endif |
| 37 | #include "dconfig.h" /* for GCC definitions */ |
| 38 | #include "decContext.h" /* context and base types */ |
| 39 | #include "decNumberLocal.h" /* decNumber local types, etc. */ |
| 40 | |
| 41 | /* compile-time endian tester [assumes sizeof(Int)>1] */ |
| 42 | static const Int mfcone=1; /* constant 1 */ |
| 43 | static const Flag *mfctop=(const Flag *)&mfcone; /* -> top byte */ |
| 44 | #define LITEND *mfctop /* named flag; 1=little-endian */ |
| 45 | |
| 46 | /* ------------------------------------------------------------------ */ |
| 47 | /* round-for-reround digits */ |
| 48 | /* ------------------------------------------------------------------ */ |
| 49 | const uByte DECSTICKYTAB[10]={1,1,2,3,4,6,6,7,8,9}; /* used if sticky */ |
| 50 | |
| 51 | /* ------------------------------------------------------------------ */ |
| 52 | /* Powers of ten (powers[n]==10**n, 0<=n<=9) */ |
| 53 | /* ------------------------------------------------------------------ */ |
| 54 | const uInt DECPOWERS[10]={1, 10, 100, 1000, 10000, 100000, 1000000, |
| 55 | 10000000, 100000000, 1000000000}; |
| 56 | |
| 57 | /* ------------------------------------------------------------------ */ |
| 58 | /* decContextClearStatus -- clear bits in current status */ |
| 59 | /* */ |
| 60 | /* context is the context structure to be queried */ |
| 61 | /* mask indicates the bits to be cleared (the status bit that */ |
| 62 | /* corresponds to each 1 bit in the mask is cleared) */ |
| 63 | /* returns context */ |
| 64 | /* */ |
| 65 | /* No error is possible. */ |
| 66 | /* ------------------------------------------------------------------ */ |
| 67 | decContext *decContextClearStatus(decContext *context, uInt mask) { |
| 68 | context->status&=~mask; |
| 69 | return context; |
| 70 | } /* decContextClearStatus */ |
| 71 | |
| 72 | /* ------------------------------------------------------------------ */ |
| 73 | /* decContextDefault -- initialize a context structure */ |
| 74 | /* */ |
| 75 | /* context is the structure to be initialized */ |
| 76 | /* kind selects the required set of default values, one of: */ |
| 77 | /* DEC_INIT_BASE -- select ANSI X3-274 defaults */ |
| 78 | /* DEC_INIT_DECIMAL32 -- select IEEE 754 defaults, 32-bit */ |
| 79 | /* DEC_INIT_DECIMAL64 -- select IEEE 754 defaults, 64-bit */ |
| 80 | /* DEC_INIT_DECIMAL128 -- select IEEE 754 defaults, 128-bit */ |
| 81 | /* For any other value a valid context is returned, but with */ |
| 82 | /* Invalid_operation set in the status field. */ |
| 83 | /* returns a context structure with the appropriate initial values. */ |
| 84 | /* ------------------------------------------------------------------ */ |
| 85 | decContext * decContextDefault(decContext *context, Int kind) { |
| 86 | /* set defaults... */ |
| 87 | context->digits=9; /* 9 digits */ |
| 88 | context->emax=DEC_MAX_EMAX; /* 9-digit exponents */ |
| 89 | context->emin=DEC_MIN_EMIN; /* .. balanced */ |
| 90 | context->round=DEC_ROUND_HALF_UP; /* 0.5 rises */ |
| 91 | context->traps=DEC_Errors; /* all but informational */ |
| 92 | context->status=0; /* cleared */ |
| 93 | context->clamp=0; /* no clamping */ |
| 94 | #if DECSUBSET |
| 95 | context->extended=0; /* cleared */ |
| 96 | #endif |
| 97 | switch (kind) { |
| 98 | case DEC_INIT_BASE: |
| 99 | /* [use defaults] */ |
| 100 | break; |
| 101 | case DEC_INIT_DECIMAL32: |
| 102 | context->digits=7; /* digits */ |
| 103 | context->emax=96; /* Emax */ |
| 104 | context->emin=-95; /* Emin */ |
| 105 | context->round=DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */ |
| 106 | context->traps=0; /* no traps set */ |
| 107 | context->clamp=1; /* clamp exponents */ |
| 108 | #if DECSUBSET |
| 109 | context->extended=1; /* set */ |
| 110 | #endif |
| 111 | break; |
| 112 | case DEC_INIT_DECIMAL64: |
| 113 | context->digits=16; /* digits */ |
| 114 | context->emax=384; /* Emax */ |
| 115 | context->emin=-383; /* Emin */ |
| 116 | context->round=DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */ |
| 117 | context->traps=0; /* no traps set */ |
| 118 | context->clamp=1; /* clamp exponents */ |
| 119 | #if DECSUBSET |
| 120 | context->extended=1; /* set */ |
| 121 | #endif |
| 122 | break; |
| 123 | case DEC_INIT_DECIMAL128: |
| 124 | context->digits=34; /* digits */ |
| 125 | context->emax=6144; /* Emax */ |
| 126 | context->emin=-6143; /* Emin */ |
| 127 | context->round=DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */ |
| 128 | context->traps=0; /* no traps set */ |
| 129 | context->clamp=1; /* clamp exponents */ |
| 130 | #if DECSUBSET |
| 131 | context->extended=1; /* set */ |
| 132 | #endif |
| 133 | break; |
| 134 | |
| 135 | default: /* invalid Kind */ |
| 136 | /* use defaults, and .. */ |
| 137 | decContextSetStatus(context, DEC_Invalid_operation); /* trap */ |
| 138 | } |
| 139 | |
| 140 | return context;} /* decContextDefault */ |
| 141 | |
| 142 | /* ------------------------------------------------------------------ */ |
| 143 | /* decContextGetRounding -- return current rounding mode */ |
| 144 | /* */ |
| 145 | /* context is the context structure to be queried */ |
| 146 | /* returns the rounding mode */ |
| 147 | /* */ |
| 148 | /* No error is possible. */ |
| 149 | /* ------------------------------------------------------------------ */ |
| 150 | enum rounding decContextGetRounding(decContext *context) { |
| 151 | return context->round; |
| 152 | } /* decContextGetRounding */ |
| 153 | |
| 154 | /* ------------------------------------------------------------------ */ |
| 155 | /* decContextGetStatus -- return current status */ |
| 156 | /* */ |
| 157 | /* context is the context structure to be queried */ |
| 158 | /* returns status */ |
| 159 | /* */ |
| 160 | /* No error is possible. */ |
| 161 | /* ------------------------------------------------------------------ */ |
| 162 | uInt decContextGetStatus(decContext *context) { |
| 163 | return context->status; |
| 164 | } /* decContextGetStatus */ |
| 165 | |
| 166 | /* ------------------------------------------------------------------ */ |
| 167 | /* decContextRestoreStatus -- restore bits in current status */ |
| 168 | /* */ |
| 169 | /* context is the context structure to be updated */ |
| 170 | /* newstatus is the source for the bits to be restored */ |
| 171 | /* mask indicates the bits to be restored (the status bit that */ |
| 172 | /* corresponds to each 1 bit in the mask is set to the value of */ |
| 173 | /* the correspnding bit in newstatus) */ |
| 174 | /* returns context */ |
| 175 | /* */ |
| 176 | /* No error is possible. */ |
| 177 | /* ------------------------------------------------------------------ */ |
| 178 | decContext *decContextRestoreStatus(decContext *context, |
| 179 | uInt newstatus, uInt mask) { |
| 180 | context->status&=~mask; /* clear the selected bits */ |
| 181 | context->status|=(mask&newstatus); /* or in the new bits */ |
| 182 | return context; |
| 183 | } /* decContextRestoreStatus */ |
| 184 | |
| 185 | /* ------------------------------------------------------------------ */ |
| 186 | /* decContextSaveStatus -- save bits in current status */ |
| 187 | /* */ |
| 188 | /* context is the context structure to be queried */ |
| 189 | /* mask indicates the bits to be saved (the status bits that */ |
| 190 | /* correspond to each 1 bit in the mask are saved) */ |
| 191 | /* returns the AND of the mask and the current status */ |
| 192 | /* */ |
| 193 | /* No error is possible. */ |
| 194 | /* ------------------------------------------------------------------ */ |
| 195 | uInt decContextSaveStatus(decContext *context, uInt mask) { |
| 196 | return context->status&mask; |
| 197 | } /* decContextSaveStatus */ |
| 198 | |
| 199 | /* ------------------------------------------------------------------ */ |
| 200 | /* decContextSetRounding -- set current rounding mode */ |
| 201 | /* */ |
| 202 | /* context is the context structure to be updated */ |
| 203 | /* newround is the value which will replace the current mode */ |
| 204 | /* returns context */ |
| 205 | /* */ |
| 206 | /* No error is possible. */ |
| 207 | /* ------------------------------------------------------------------ */ |
| 208 | decContext *decContextSetRounding(decContext *context, |
| 209 | enum rounding newround) { |
| 210 | context->round=newround; |
| 211 | return context; |
| 212 | } /* decContextSetRounding */ |
| 213 | |
| 214 | /* ------------------------------------------------------------------ */ |
| 215 | /* decContextSetStatus -- set status and raise trap if appropriate */ |
| 216 | /* */ |
| 217 | /* context is the context structure to be updated */ |
| 218 | /* status is the DEC_ exception code */ |
| 219 | /* returns the context structure */ |
| 220 | /* */ |
| 221 | /* Control may never return from this routine, if there is a signal */ |
| 222 | /* handler and it takes a long jump. */ |
| 223 | /* ------------------------------------------------------------------ */ |
| 224 | decContext * decContextSetStatus(decContext *context, uInt status) { |
| 225 | context->status|=status; |
| 226 | if (status & context->traps) raise(SIGFPE); |
| 227 | return context;} /* decContextSetStatus */ |
| 228 | |
| 229 | /* ------------------------------------------------------------------ */ |
| 230 | /* decContextSetStatusFromString -- set status from a string + trap */ |
| 231 | /* */ |
| 232 | /* context is the context structure to be updated */ |
| 233 | /* string is a string exactly equal to one that might be returned */ |
| 234 | /* by decContextStatusToString */ |
| 235 | /* */ |
| 236 | /* The status bit corresponding to the string is set, and a trap */ |
| 237 | /* is raised if appropriate. */ |
| 238 | /* */ |
| 239 | /* returns the context structure, unless the string is equal to */ |
| 240 | /* DEC_Condition_MU or is not recognized. In these cases NULL is */ |
| 241 | /* returned. */ |
| 242 | /* ------------------------------------------------------------------ */ |
| 243 | decContext * decContextSetStatusFromString(decContext *context, |
| 244 | const char *string) { |
| 245 | if (strcmp(string, DEC_Condition_CS)==0) |
| 246 | return decContextSetStatus(context, DEC_Conversion_syntax); |
| 247 | if (strcmp(string, DEC_Condition_DZ)==0) |
| 248 | return decContextSetStatus(context, DEC_Division_by_zero); |
| 249 | if (strcmp(string, DEC_Condition_DI)==0) |
| 250 | return decContextSetStatus(context, DEC_Division_impossible); |
| 251 | if (strcmp(string, DEC_Condition_DU)==0) |
| 252 | return decContextSetStatus(context, DEC_Division_undefined); |
| 253 | if (strcmp(string, DEC_Condition_IE)==0) |
| 254 | return decContextSetStatus(context, DEC_Inexact); |
| 255 | if (strcmp(string, DEC_Condition_IS)==0) |
| 256 | return decContextSetStatus(context, DEC_Insufficient_storage); |
| 257 | if (strcmp(string, DEC_Condition_IC)==0) |
| 258 | return decContextSetStatus(context, DEC_Invalid_context); |
| 259 | if (strcmp(string, DEC_Condition_IO)==0) |
| 260 | return decContextSetStatus(context, DEC_Invalid_operation); |
| 261 | #if DECSUBSET |
| 262 | if (strcmp(string, DEC_Condition_LD)==0) |
| 263 | return decContextSetStatus(context, DEC_Lost_digits); |
| 264 | #endif |
| 265 | if (strcmp(string, DEC_Condition_OV)==0) |
| 266 | return decContextSetStatus(context, DEC_Overflow); |
| 267 | if (strcmp(string, DEC_Condition_PA)==0) |
| 268 | return decContextSetStatus(context, DEC_Clamped); |
| 269 | if (strcmp(string, DEC_Condition_RO)==0) |
| 270 | return decContextSetStatus(context, DEC_Rounded); |
| 271 | if (strcmp(string, DEC_Condition_SU)==0) |
| 272 | return decContextSetStatus(context, DEC_Subnormal); |
| 273 | if (strcmp(string, DEC_Condition_UN)==0) |
| 274 | return decContextSetStatus(context, DEC_Underflow); |
| 275 | if (strcmp(string, DEC_Condition_ZE)==0) |
| 276 | return context; |
| 277 | return NULL; /* Multiple status, or unknown */ |
| 278 | } /* decContextSetStatusFromString */ |
| 279 | |
| 280 | /* ------------------------------------------------------------------ */ |
| 281 | /* decContextSetStatusFromStringQuiet -- set status from a string */ |
| 282 | /* */ |
| 283 | /* context is the context structure to be updated */ |
| 284 | /* string is a string exactly equal to one that might be returned */ |
| 285 | /* by decContextStatusToString */ |
| 286 | /* */ |
| 287 | /* The status bit corresponding to the string is set; no trap is */ |
| 288 | /* raised. */ |
| 289 | /* */ |
| 290 | /* returns the context structure, unless the string is equal to */ |
| 291 | /* DEC_Condition_MU or is not recognized. In these cases NULL is */ |
| 292 | /* returned. */ |
| 293 | /* ------------------------------------------------------------------ */ |
| 294 | decContext * decContextSetStatusFromStringQuiet(decContext *context, |
| 295 | const char *string) { |
| 296 | if (strcmp(string, DEC_Condition_CS)==0) |
| 297 | return decContextSetStatusQuiet(context, DEC_Conversion_syntax); |
| 298 | if (strcmp(string, DEC_Condition_DZ)==0) |
| 299 | return decContextSetStatusQuiet(context, DEC_Division_by_zero); |
| 300 | if (strcmp(string, DEC_Condition_DI)==0) |
| 301 | return decContextSetStatusQuiet(context, DEC_Division_impossible); |
| 302 | if (strcmp(string, DEC_Condition_DU)==0) |
| 303 | return decContextSetStatusQuiet(context, DEC_Division_undefined); |
| 304 | if (strcmp(string, DEC_Condition_IE)==0) |
| 305 | return decContextSetStatusQuiet(context, DEC_Inexact); |
| 306 | if (strcmp(string, DEC_Condition_IS)==0) |
| 307 | return decContextSetStatusQuiet(context, DEC_Insufficient_storage); |
| 308 | if (strcmp(string, DEC_Condition_IC)==0) |
| 309 | return decContextSetStatusQuiet(context, DEC_Invalid_context); |
| 310 | if (strcmp(string, DEC_Condition_IO)==0) |
| 311 | return decContextSetStatusQuiet(context, DEC_Invalid_operation); |
| 312 | #if DECSUBSET |
| 313 | if (strcmp(string, DEC_Condition_LD)==0) |
| 314 | return decContextSetStatusQuiet(context, DEC_Lost_digits); |
| 315 | #endif |
| 316 | if (strcmp(string, DEC_Condition_OV)==0) |
| 317 | return decContextSetStatusQuiet(context, DEC_Overflow); |
| 318 | if (strcmp(string, DEC_Condition_PA)==0) |
| 319 | return decContextSetStatusQuiet(context, DEC_Clamped); |
| 320 | if (strcmp(string, DEC_Condition_RO)==0) |
| 321 | return decContextSetStatusQuiet(context, DEC_Rounded); |
| 322 | if (strcmp(string, DEC_Condition_SU)==0) |
| 323 | return decContextSetStatusQuiet(context, DEC_Subnormal); |
| 324 | if (strcmp(string, DEC_Condition_UN)==0) |
| 325 | return decContextSetStatusQuiet(context, DEC_Underflow); |
| 326 | if (strcmp(string, DEC_Condition_ZE)==0) |
| 327 | return context; |
| 328 | return NULL; /* Multiple status, or unknown */ |
| 329 | } /* decContextSetStatusFromStringQuiet */ |
| 330 | |
| 331 | /* ------------------------------------------------------------------ */ |
| 332 | /* decContextSetStatusQuiet -- set status without trap */ |
| 333 | /* */ |
| 334 | /* context is the context structure to be updated */ |
| 335 | /* status is the DEC_ exception code */ |
| 336 | /* returns the context structure */ |
| 337 | /* */ |
| 338 | /* No error is possible. */ |
| 339 | /* ------------------------------------------------------------------ */ |
| 340 | decContext * decContextSetStatusQuiet(decContext *context, uInt status) { |
| 341 | context->status|=status; |
| 342 | return context;} /* decContextSetStatusQuiet */ |
| 343 | |
| 344 | /* ------------------------------------------------------------------ */ |
| 345 | /* decContextStatusToString -- convert status flags to a string */ |
| 346 | /* */ |
| 347 | /* context is a context with valid status field */ |
| 348 | /* */ |
| 349 | /* returns a constant string describing the condition. If multiple */ |
| 350 | /* (or no) flags are set, a generic constant message is returned. */ |
| 351 | /* ------------------------------------------------------------------ */ |
| 352 | const char *decContextStatusToString(const decContext *context) { |
| 353 | Int status=context->status; |
| 354 | |
| 355 | /* test the five IEEE first, as some of the others are ambiguous when */ |
| 356 | /* DECEXTFLAG=0 */ |
| 357 | if (status==DEC_Invalid_operation ) return DEC_Condition_IO; |
| 358 | if (status==DEC_Division_by_zero ) return DEC_Condition_DZ; |
| 359 | if (status==DEC_Overflow ) return DEC_Condition_OV; |
| 360 | if (status==DEC_Underflow ) return DEC_Condition_UN; |
| 361 | if (status==DEC_Inexact ) return DEC_Condition_IE; |
| 362 | |
| 363 | if (status==DEC_Division_impossible ) return DEC_Condition_DI; |
| 364 | if (status==DEC_Division_undefined ) return DEC_Condition_DU; |
| 365 | if (status==DEC_Rounded ) return DEC_Condition_RO; |
| 366 | if (status==DEC_Clamped ) return DEC_Condition_PA; |
| 367 | if (status==DEC_Subnormal ) return DEC_Condition_SU; |
| 368 | if (status==DEC_Conversion_syntax ) return DEC_Condition_CS; |
| 369 | if (status==DEC_Insufficient_storage ) return DEC_Condition_IS; |
| 370 | if (status==DEC_Invalid_context ) return DEC_Condition_IC; |
| 371 | #if DECSUBSET |
| 372 | if (status==DEC_Lost_digits ) return DEC_Condition_LD; |
| 373 | #endif |
| 374 | if (status==0 ) return DEC_Condition_ZE; |
| 375 | return DEC_Condition_MU; /* Multiple errors */ |
| 376 | } /* decContextStatusToString */ |
| 377 | |
| 378 | /* ------------------------------------------------------------------ */ |
| 379 | /* decContextTestEndian -- test whether DECLITEND is set correctly */ |
| 380 | /* */ |
| 381 | /* quiet is 1 to suppress message; 0 otherwise */ |
| 382 | /* returns 0 if DECLITEND is correct */ |
| 383 | /* 1 if DECLITEND is incorrect and should be 1 */ |
| 384 | /* -1 if DECLITEND is incorrect and should be 0 */ |
| 385 | /* */ |
| 386 | /* A message is displayed if the return value is not 0 and quiet==0. */ |
| 387 | /* */ |
| 388 | /* No error is possible. */ |
| 389 | /* ------------------------------------------------------------------ */ |
| 390 | Int decContextTestEndian(Flag quiet) { |
| 391 | Int res=0; /* optimist */ |
| 392 | uInt dle=(uInt)DECLITEND; /* unsign */ |
| 393 | if (dle>1) dle=1; /* ensure 0 or 1 */ |
| 394 | |
| 395 | if (LITEND!=DECLITEND) { |
| 396 | if (!quiet) { |
| 397 | #if DECCHECK |
| 398 | const char *adj; |
| 399 | if (LITEND) adj="little"; |
| 400 | else adj="big"; |
| 401 | printf("Warning: DECLITEND is set to %d, but this computer appears to be %s-endian\n", |
| 402 | DECLITEND, adj); |
| 403 | #endif |
| 404 | } |
| 405 | res=(Int)LITEND-dle; |
| 406 | } |
| 407 | return res; |
| 408 | } /* decContextTestEndian */ |
| 409 | |
| 410 | /* ------------------------------------------------------------------ */ |
| 411 | /* decContextTestSavedStatus -- test bits in saved status */ |
| 412 | /* */ |
| 413 | /* oldstatus is the status word to be tested */ |
| 414 | /* mask indicates the bits to be tested (the oldstatus bits that */ |
| 415 | /* correspond to each 1 bit in the mask are tested) */ |
| 416 | /* returns 1 if any of the tested bits are 1, or 0 otherwise */ |
| 417 | /* */ |
| 418 | /* No error is possible. */ |
| 419 | /* ------------------------------------------------------------------ */ |
| 420 | uInt decContextTestSavedStatus(uInt oldstatus, uInt mask) { |
| 421 | return (oldstatus&mask)!=0; |
| 422 | } /* decContextTestSavedStatus */ |
| 423 | |
| 424 | /* ------------------------------------------------------------------ */ |
| 425 | /* decContextTestStatus -- test bits in current status */ |
| 426 | /* */ |
| 427 | /* context is the context structure to be updated */ |
| 428 | /* mask indicates the bits to be tested (the status bits that */ |
| 429 | /* correspond to each 1 bit in the mask are tested) */ |
| 430 | /* returns 1 if any of the tested bits are 1, or 0 otherwise */ |
| 431 | /* */ |
| 432 | /* No error is possible. */ |
| 433 | /* ------------------------------------------------------------------ */ |
| 434 | uInt decContextTestStatus(decContext *context, uInt mask) { |
| 435 | return (context->status&mask)!=0; |
| 436 | } /* decContextTestStatus */ |
| 437 | |
| 438 | /* ------------------------------------------------------------------ */ |
| 439 | /* decContextZeroStatus -- clear all status bits */ |
| 440 | /* */ |
| 441 | /* context is the context structure to be updated */ |
| 442 | /* returns context */ |
| 443 | /* */ |
| 444 | /* No error is possible. */ |
| 445 | /* ------------------------------------------------------------------ */ |
| 446 | decContext *decContextZeroStatus(decContext *context) { |
| 447 | context->status=0; |
| 448 | return context; |
| 449 | } /* decContextZeroStatus */ |
| 450 | |