APInt.cpp revision 221345
1//===-- APInt.cpp - Implement APInt class ---------------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements a class to represent arbitrary precision integer 11// constant values and provide a variety of arithmetic operations on them. 12// 13//===----------------------------------------------------------------------===// 14 15#define DEBUG_TYPE "apint" 16#include "llvm/ADT/APInt.h" 17#include "llvm/ADT/StringRef.h" 18#include "llvm/ADT/FoldingSet.h" 19#include "llvm/ADT/SmallString.h" 20#include "llvm/Support/Debug.h" 21#include "llvm/Support/ErrorHandling.h" 22#include "llvm/Support/MathExtras.h" 23#include "llvm/Support/raw_ostream.h" 24#include <cmath> 25#include <limits> 26#include <cstring> 27#include <cstdlib> 28using namespace llvm; 29 30/// A utility function for allocating memory, checking for allocation failures, 31/// and ensuring the contents are zeroed. 32inline static uint64_t* getClearedMemory(unsigned numWords) { 33 uint64_t * result = new uint64_t[numWords]; 34 assert(result && "APInt memory allocation fails!"); 35 memset(result, 0, numWords * sizeof(uint64_t)); 36 return result; 37} 38 39/// A utility function for allocating memory and checking for allocation 40/// failure. The content is not zeroed. 41inline static uint64_t* getMemory(unsigned numWords) { 42 uint64_t * result = new uint64_t[numWords]; 43 assert(result && "APInt memory allocation fails!"); 44 return result; 45} 46 47/// A utility function that converts a character to a digit. 48inline static unsigned getDigit(char cdigit, uint8_t radix) { 49 unsigned r; 50 51 if (radix == 16) { 52 r = cdigit - '0'; 53 if (r <= 9) 54 return r; 55 56 r = cdigit - 'A'; 57 if (r <= 5) 58 return r + 10; 59 60 r = cdigit - 'a'; 61 if (r <= 5) 62 return r + 10; 63 } 64 65 r = cdigit - '0'; 66 if (r < radix) 67 return r; 68 69 return -1U; 70} 71 72 73void APInt::initSlowCase(unsigned numBits, uint64_t val, bool isSigned) { 74 pVal = getClearedMemory(getNumWords()); 75 pVal[0] = val; 76 if (isSigned && int64_t(val) < 0) 77 for (unsigned i = 1; i < getNumWords(); ++i) 78 pVal[i] = -1ULL; 79} 80 81void APInt::initSlowCase(const APInt& that) { 82 pVal = getMemory(getNumWords()); 83 memcpy(pVal, that.pVal, getNumWords() * APINT_WORD_SIZE); 84} 85 86 87APInt::APInt(unsigned numBits, unsigned numWords, const uint64_t bigVal[]) 88 : BitWidth(numBits), VAL(0) { 89 assert(BitWidth && "Bitwidth too small"); 90 assert(bigVal && "Null pointer detected!"); 91 if (isSingleWord()) 92 VAL = bigVal[0]; 93 else { 94 // Get memory, cleared to 0 95 pVal = getClearedMemory(getNumWords()); 96 // Calculate the number of words to copy 97 unsigned words = std::min<unsigned>(numWords, getNumWords()); 98 // Copy the words from bigVal to pVal 99 memcpy(pVal, bigVal, words * APINT_WORD_SIZE); 100 } 101 // Make sure unused high bits are cleared 102 clearUnusedBits(); 103} 104 105APInt::APInt(unsigned numbits, StringRef Str, uint8_t radix) 106 : BitWidth(numbits), VAL(0) { 107 assert(BitWidth && "Bitwidth too small"); 108 fromString(numbits, Str, radix); 109} 110 111APInt& APInt::AssignSlowCase(const APInt& RHS) { 112 // Don't do anything for X = X 113 if (this == &RHS) 114 return *this; 115 116 if (BitWidth == RHS.getBitWidth()) { 117 // assume same bit-width single-word case is already handled 118 assert(!isSingleWord()); 119 memcpy(pVal, RHS.pVal, getNumWords() * APINT_WORD_SIZE); 120 return *this; 121 } 122 123 if (isSingleWord()) { 124 // assume case where both are single words is already handled 125 assert(!RHS.isSingleWord()); 126 VAL = 0; 127 pVal = getMemory(RHS.getNumWords()); 128 memcpy(pVal, RHS.pVal, RHS.getNumWords() * APINT_WORD_SIZE); 129 } else if (getNumWords() == RHS.getNumWords()) 130 memcpy(pVal, RHS.pVal, RHS.getNumWords() * APINT_WORD_SIZE); 131 else if (RHS.isSingleWord()) { 132 delete [] pVal; 133 VAL = RHS.VAL; 134 } else { 135 delete [] pVal; 136 pVal = getMemory(RHS.getNumWords()); 137 memcpy(pVal, RHS.pVal, RHS.getNumWords() * APINT_WORD_SIZE); 138 } 139 BitWidth = RHS.BitWidth; 140 return clearUnusedBits(); 141} 142 143APInt& APInt::operator=(uint64_t RHS) { 144 if (isSingleWord()) 145 VAL = RHS; 146 else { 147 pVal[0] = RHS; 148 memset(pVal+1, 0, (getNumWords() - 1) * APINT_WORD_SIZE); 149 } 150 return clearUnusedBits(); 151} 152 153/// Profile - This method 'profiles' an APInt for use with FoldingSet. 154void APInt::Profile(FoldingSetNodeID& ID) const { 155 ID.AddInteger(BitWidth); 156 157 if (isSingleWord()) { 158 ID.AddInteger(VAL); 159 return; 160 } 161 162 unsigned NumWords = getNumWords(); 163 for (unsigned i = 0; i < NumWords; ++i) 164 ID.AddInteger(pVal[i]); 165} 166 167/// add_1 - This function adds a single "digit" integer, y, to the multiple 168/// "digit" integer array, x[]. x[] is modified to reflect the addition and 169/// 1 is returned if there is a carry out, otherwise 0 is returned. 170/// @returns the carry of the addition. 171static bool add_1(uint64_t dest[], uint64_t x[], unsigned len, uint64_t y) { 172 for (unsigned i = 0; i < len; ++i) { 173 dest[i] = y + x[i]; 174 if (dest[i] < y) 175 y = 1; // Carry one to next digit. 176 else { 177 y = 0; // No need to carry so exit early 178 break; 179 } 180 } 181 return y; 182} 183 184/// @brief Prefix increment operator. Increments the APInt by one. 185APInt& APInt::operator++() { 186 if (isSingleWord()) 187 ++VAL; 188 else 189 add_1(pVal, pVal, getNumWords(), 1); 190 return clearUnusedBits(); 191} 192 193/// sub_1 - This function subtracts a single "digit" (64-bit word), y, from 194/// the multi-digit integer array, x[], propagating the borrowed 1 value until 195/// no further borrowing is neeeded or it runs out of "digits" in x. The result 196/// is 1 if "borrowing" exhausted the digits in x, or 0 if x was not exhausted. 197/// In other words, if y > x then this function returns 1, otherwise 0. 198/// @returns the borrow out of the subtraction 199static bool sub_1(uint64_t x[], unsigned len, uint64_t y) { 200 for (unsigned i = 0; i < len; ++i) { 201 uint64_t X = x[i]; 202 x[i] -= y; 203 if (y > X) 204 y = 1; // We have to "borrow 1" from next "digit" 205 else { 206 y = 0; // No need to borrow 207 break; // Remaining digits are unchanged so exit early 208 } 209 } 210 return bool(y); 211} 212 213/// @brief Prefix decrement operator. Decrements the APInt by one. 214APInt& APInt::operator--() { 215 if (isSingleWord()) 216 --VAL; 217 else 218 sub_1(pVal, getNumWords(), 1); 219 return clearUnusedBits(); 220} 221 222/// add - This function adds the integer array x to the integer array Y and 223/// places the result in dest. 224/// @returns the carry out from the addition 225/// @brief General addition of 64-bit integer arrays 226static bool add(uint64_t *dest, const uint64_t *x, const uint64_t *y, 227 unsigned len) { 228 bool carry = false; 229 for (unsigned i = 0; i< len; ++i) { 230 uint64_t limit = std::min(x[i],y[i]); // must come first in case dest == x 231 dest[i] = x[i] + y[i] + carry; 232 carry = dest[i] < limit || (carry && dest[i] == limit); 233 } 234 return carry; 235} 236 237/// Adds the RHS APint to this APInt. 238/// @returns this, after addition of RHS. 239/// @brief Addition assignment operator. 240APInt& APInt::operator+=(const APInt& RHS) { 241 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 242 if (isSingleWord()) 243 VAL += RHS.VAL; 244 else { 245 add(pVal, pVal, RHS.pVal, getNumWords()); 246 } 247 return clearUnusedBits(); 248} 249 250/// Subtracts the integer array y from the integer array x 251/// @returns returns the borrow out. 252/// @brief Generalized subtraction of 64-bit integer arrays. 253static bool sub(uint64_t *dest, const uint64_t *x, const uint64_t *y, 254 unsigned len) { 255 bool borrow = false; 256 for (unsigned i = 0; i < len; ++i) { 257 uint64_t x_tmp = borrow ? x[i] - 1 : x[i]; 258 borrow = y[i] > x_tmp || (borrow && x[i] == 0); 259 dest[i] = x_tmp - y[i]; 260 } 261 return borrow; 262} 263 264/// Subtracts the RHS APInt from this APInt 265/// @returns this, after subtraction 266/// @brief Subtraction assignment operator. 267APInt& APInt::operator-=(const APInt& RHS) { 268 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 269 if (isSingleWord()) 270 VAL -= RHS.VAL; 271 else 272 sub(pVal, pVal, RHS.pVal, getNumWords()); 273 return clearUnusedBits(); 274} 275 276/// Multiplies an integer array, x, by a uint64_t integer and places the result 277/// into dest. 278/// @returns the carry out of the multiplication. 279/// @brief Multiply a multi-digit APInt by a single digit (64-bit) integer. 280static uint64_t mul_1(uint64_t dest[], uint64_t x[], unsigned len, uint64_t y) { 281 // Split y into high 32-bit part (hy) and low 32-bit part (ly) 282 uint64_t ly = y & 0xffffffffULL, hy = y >> 32; 283 uint64_t carry = 0; 284 285 // For each digit of x. 286 for (unsigned i = 0; i < len; ++i) { 287 // Split x into high and low words 288 uint64_t lx = x[i] & 0xffffffffULL; 289 uint64_t hx = x[i] >> 32; 290 // hasCarry - A flag to indicate if there is a carry to the next digit. 291 // hasCarry == 0, no carry 292 // hasCarry == 1, has carry 293 // hasCarry == 2, no carry and the calculation result == 0. 294 uint8_t hasCarry = 0; 295 dest[i] = carry + lx * ly; 296 // Determine if the add above introduces carry. 297 hasCarry = (dest[i] < carry) ? 1 : 0; 298 carry = hx * ly + (dest[i] >> 32) + (hasCarry ? (1ULL << 32) : 0); 299 // The upper limit of carry can be (2^32 - 1)(2^32 - 1) + 300 // (2^32 - 1) + 2^32 = 2^64. 301 hasCarry = (!carry && hasCarry) ? 1 : (!carry ? 2 : 0); 302 303 carry += (lx * hy) & 0xffffffffULL; 304 dest[i] = (carry << 32) | (dest[i] & 0xffffffffULL); 305 carry = (((!carry && hasCarry != 2) || hasCarry == 1) ? (1ULL << 32) : 0) + 306 (carry >> 32) + ((lx * hy) >> 32) + hx * hy; 307 } 308 return carry; 309} 310 311/// Multiplies integer array x by integer array y and stores the result into 312/// the integer array dest. Note that dest's size must be >= xlen + ylen. 313/// @brief Generalized multiplicate of integer arrays. 314static void mul(uint64_t dest[], uint64_t x[], unsigned xlen, uint64_t y[], 315 unsigned ylen) { 316 dest[xlen] = mul_1(dest, x, xlen, y[0]); 317 for (unsigned i = 1; i < ylen; ++i) { 318 uint64_t ly = y[i] & 0xffffffffULL, hy = y[i] >> 32; 319 uint64_t carry = 0, lx = 0, hx = 0; 320 for (unsigned j = 0; j < xlen; ++j) { 321 lx = x[j] & 0xffffffffULL; 322 hx = x[j] >> 32; 323 // hasCarry - A flag to indicate if has carry. 324 // hasCarry == 0, no carry 325 // hasCarry == 1, has carry 326 // hasCarry == 2, no carry and the calculation result == 0. 327 uint8_t hasCarry = 0; 328 uint64_t resul = carry + lx * ly; 329 hasCarry = (resul < carry) ? 1 : 0; 330 carry = (hasCarry ? (1ULL << 32) : 0) + hx * ly + (resul >> 32); 331 hasCarry = (!carry && hasCarry) ? 1 : (!carry ? 2 : 0); 332 333 carry += (lx * hy) & 0xffffffffULL; 334 resul = (carry << 32) | (resul & 0xffffffffULL); 335 dest[i+j] += resul; 336 carry = (((!carry && hasCarry != 2) || hasCarry == 1) ? (1ULL << 32) : 0)+ 337 (carry >> 32) + (dest[i+j] < resul ? 1 : 0) + 338 ((lx * hy) >> 32) + hx * hy; 339 } 340 dest[i+xlen] = carry; 341 } 342} 343 344APInt& APInt::operator*=(const APInt& RHS) { 345 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 346 if (isSingleWord()) { 347 VAL *= RHS.VAL; 348 clearUnusedBits(); 349 return *this; 350 } 351 352 // Get some bit facts about LHS and check for zero 353 unsigned lhsBits = getActiveBits(); 354 unsigned lhsWords = !lhsBits ? 0 : whichWord(lhsBits - 1) + 1; 355 if (!lhsWords) 356 // 0 * X ===> 0 357 return *this; 358 359 // Get some bit facts about RHS and check for zero 360 unsigned rhsBits = RHS.getActiveBits(); 361 unsigned rhsWords = !rhsBits ? 0 : whichWord(rhsBits - 1) + 1; 362 if (!rhsWords) { 363 // X * 0 ===> 0 364 clearAllBits(); 365 return *this; 366 } 367 368 // Allocate space for the result 369 unsigned destWords = rhsWords + lhsWords; 370 uint64_t *dest = getMemory(destWords); 371 372 // Perform the long multiply 373 mul(dest, pVal, lhsWords, RHS.pVal, rhsWords); 374 375 // Copy result back into *this 376 clearAllBits(); 377 unsigned wordsToCopy = destWords >= getNumWords() ? getNumWords() : destWords; 378 memcpy(pVal, dest, wordsToCopy * APINT_WORD_SIZE); 379 380 // delete dest array and return 381 delete[] dest; 382 return *this; 383} 384 385APInt& APInt::operator&=(const APInt& RHS) { 386 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 387 if (isSingleWord()) { 388 VAL &= RHS.VAL; 389 return *this; 390 } 391 unsigned numWords = getNumWords(); 392 for (unsigned i = 0; i < numWords; ++i) 393 pVal[i] &= RHS.pVal[i]; 394 return *this; 395} 396 397APInt& APInt::operator|=(const APInt& RHS) { 398 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 399 if (isSingleWord()) { 400 VAL |= RHS.VAL; 401 return *this; 402 } 403 unsigned numWords = getNumWords(); 404 for (unsigned i = 0; i < numWords; ++i) 405 pVal[i] |= RHS.pVal[i]; 406 return *this; 407} 408 409APInt& APInt::operator^=(const APInt& RHS) { 410 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 411 if (isSingleWord()) { 412 VAL ^= RHS.VAL; 413 this->clearUnusedBits(); 414 return *this; 415 } 416 unsigned numWords = getNumWords(); 417 for (unsigned i = 0; i < numWords; ++i) 418 pVal[i] ^= RHS.pVal[i]; 419 return clearUnusedBits(); 420} 421 422APInt APInt::AndSlowCase(const APInt& RHS) const { 423 unsigned numWords = getNumWords(); 424 uint64_t* val = getMemory(numWords); 425 for (unsigned i = 0; i < numWords; ++i) 426 val[i] = pVal[i] & RHS.pVal[i]; 427 return APInt(val, getBitWidth()); 428} 429 430APInt APInt::OrSlowCase(const APInt& RHS) const { 431 unsigned numWords = getNumWords(); 432 uint64_t *val = getMemory(numWords); 433 for (unsigned i = 0; i < numWords; ++i) 434 val[i] = pVal[i] | RHS.pVal[i]; 435 return APInt(val, getBitWidth()); 436} 437 438APInt APInt::XorSlowCase(const APInt& RHS) const { 439 unsigned numWords = getNumWords(); 440 uint64_t *val = getMemory(numWords); 441 for (unsigned i = 0; i < numWords; ++i) 442 val[i] = pVal[i] ^ RHS.pVal[i]; 443 444 // 0^0==1 so clear the high bits in case they got set. 445 return APInt(val, getBitWidth()).clearUnusedBits(); 446} 447 448bool APInt::operator !() const { 449 if (isSingleWord()) 450 return !VAL; 451 452 for (unsigned i = 0; i < getNumWords(); ++i) 453 if (pVal[i]) 454 return false; 455 return true; 456} 457 458APInt APInt::operator*(const APInt& RHS) const { 459 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 460 if (isSingleWord()) 461 return APInt(BitWidth, VAL * RHS.VAL); 462 APInt Result(*this); 463 Result *= RHS; 464 return Result.clearUnusedBits(); 465} 466 467APInt APInt::operator+(const APInt& RHS) const { 468 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 469 if (isSingleWord()) 470 return APInt(BitWidth, VAL + RHS.VAL); 471 APInt Result(BitWidth, 0); 472 add(Result.pVal, this->pVal, RHS.pVal, getNumWords()); 473 return Result.clearUnusedBits(); 474} 475 476APInt APInt::operator-(const APInt& RHS) const { 477 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 478 if (isSingleWord()) 479 return APInt(BitWidth, VAL - RHS.VAL); 480 APInt Result(BitWidth, 0); 481 sub(Result.pVal, this->pVal, RHS.pVal, getNumWords()); 482 return Result.clearUnusedBits(); 483} 484 485bool APInt::operator[](unsigned bitPosition) const { 486 assert(bitPosition < getBitWidth() && "Bit position out of bounds!"); 487 return (maskBit(bitPosition) & 488 (isSingleWord() ? VAL : pVal[whichWord(bitPosition)])) != 0; 489} 490 491bool APInt::EqualSlowCase(const APInt& RHS) const { 492 // Get some facts about the number of bits used in the two operands. 493 unsigned n1 = getActiveBits(); 494 unsigned n2 = RHS.getActiveBits(); 495 496 // If the number of bits isn't the same, they aren't equal 497 if (n1 != n2) 498 return false; 499 500 // If the number of bits fits in a word, we only need to compare the low word. 501 if (n1 <= APINT_BITS_PER_WORD) 502 return pVal[0] == RHS.pVal[0]; 503 504 // Otherwise, compare everything 505 for (int i = whichWord(n1 - 1); i >= 0; --i) 506 if (pVal[i] != RHS.pVal[i]) 507 return false; 508 return true; 509} 510 511bool APInt::EqualSlowCase(uint64_t Val) const { 512 unsigned n = getActiveBits(); 513 if (n <= APINT_BITS_PER_WORD) 514 return pVal[0] == Val; 515 else 516 return false; 517} 518 519bool APInt::ult(const APInt& RHS) const { 520 assert(BitWidth == RHS.BitWidth && "Bit widths must be same for comparison"); 521 if (isSingleWord()) 522 return VAL < RHS.VAL; 523 524 // Get active bit length of both operands 525 unsigned n1 = getActiveBits(); 526 unsigned n2 = RHS.getActiveBits(); 527 528 // If magnitude of LHS is less than RHS, return true. 529 if (n1 < n2) 530 return true; 531 532 // If magnitude of RHS is greather than LHS, return false. 533 if (n2 < n1) 534 return false; 535 536 // If they bot fit in a word, just compare the low order word 537 if (n1 <= APINT_BITS_PER_WORD && n2 <= APINT_BITS_PER_WORD) 538 return pVal[0] < RHS.pVal[0]; 539 540 // Otherwise, compare all words 541 unsigned topWord = whichWord(std::max(n1,n2)-1); 542 for (int i = topWord; i >= 0; --i) { 543 if (pVal[i] > RHS.pVal[i]) 544 return false; 545 if (pVal[i] < RHS.pVal[i]) 546 return true; 547 } 548 return false; 549} 550 551bool APInt::slt(const APInt& RHS) const { 552 assert(BitWidth == RHS.BitWidth && "Bit widths must be same for comparison"); 553 if (isSingleWord()) { 554 int64_t lhsSext = (int64_t(VAL) << (64-BitWidth)) >> (64-BitWidth); 555 int64_t rhsSext = (int64_t(RHS.VAL) << (64-BitWidth)) >> (64-BitWidth); 556 return lhsSext < rhsSext; 557 } 558 559 APInt lhs(*this); 560 APInt rhs(RHS); 561 bool lhsNeg = isNegative(); 562 bool rhsNeg = rhs.isNegative(); 563 if (lhsNeg) { 564 // Sign bit is set so perform two's complement to make it positive 565 lhs.flipAllBits(); 566 lhs++; 567 } 568 if (rhsNeg) { 569 // Sign bit is set so perform two's complement to make it positive 570 rhs.flipAllBits(); 571 rhs++; 572 } 573 574 // Now we have unsigned values to compare so do the comparison if necessary 575 // based on the negativeness of the values. 576 if (lhsNeg) 577 if (rhsNeg) 578 return lhs.ugt(rhs); 579 else 580 return true; 581 else if (rhsNeg) 582 return false; 583 else 584 return lhs.ult(rhs); 585} 586 587void APInt::setBit(unsigned bitPosition) { 588 if (isSingleWord()) 589 VAL |= maskBit(bitPosition); 590 else 591 pVal[whichWord(bitPosition)] |= maskBit(bitPosition); 592} 593 594/// Set the given bit to 0 whose position is given as "bitPosition". 595/// @brief Set a given bit to 0. 596void APInt::clearBit(unsigned bitPosition) { 597 if (isSingleWord()) 598 VAL &= ~maskBit(bitPosition); 599 else 600 pVal[whichWord(bitPosition)] &= ~maskBit(bitPosition); 601} 602 603/// @brief Toggle every bit to its opposite value. 604 605/// Toggle a given bit to its opposite value whose position is given 606/// as "bitPosition". 607/// @brief Toggles a given bit to its opposite value. 608void APInt::flipBit(unsigned bitPosition) { 609 assert(bitPosition < BitWidth && "Out of the bit-width range!"); 610 if ((*this)[bitPosition]) clearBit(bitPosition); 611 else setBit(bitPosition); 612} 613 614unsigned APInt::getBitsNeeded(StringRef str, uint8_t radix) { 615 assert(!str.empty() && "Invalid string length"); 616 assert((radix == 10 || radix == 8 || radix == 16 || radix == 2) && 617 "Radix should be 2, 8, 10, or 16!"); 618 619 size_t slen = str.size(); 620 621 // Each computation below needs to know if it's negative. 622 StringRef::iterator p = str.begin(); 623 unsigned isNegative = *p == '-'; 624 if (*p == '-' || *p == '+') { 625 p++; 626 slen--; 627 assert(slen && "String is only a sign, needs a value."); 628 } 629 630 // For radixes of power-of-two values, the bits required is accurately and 631 // easily computed 632 if (radix == 2) 633 return slen + isNegative; 634 if (radix == 8) 635 return slen * 3 + isNegative; 636 if (radix == 16) 637 return slen * 4 + isNegative; 638 639 // This is grossly inefficient but accurate. We could probably do something 640 // with a computation of roughly slen*64/20 and then adjust by the value of 641 // the first few digits. But, I'm not sure how accurate that could be. 642 643 // Compute a sufficient number of bits that is always large enough but might 644 // be too large. This avoids the assertion in the constructor. This 645 // calculation doesn't work appropriately for the numbers 0-9, so just use 4 646 // bits in that case. 647 unsigned sufficient = slen == 1 ? 4 : slen * 64/18; 648 649 // Convert to the actual binary value. 650 APInt tmp(sufficient, StringRef(p, slen), radix); 651 652 // Compute how many bits are required. If the log is infinite, assume we need 653 // just bit. 654 unsigned log = tmp.logBase2(); 655 if (log == (unsigned)-1) { 656 return isNegative + 1; 657 } else { 658 return isNegative + log + 1; 659 } 660} 661 662// From http://www.burtleburtle.net, byBob Jenkins. 663// When targeting x86, both GCC and LLVM seem to recognize this as a 664// rotate instruction. 665#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k)))) 666 667// From http://www.burtleburtle.net, by Bob Jenkins. 668#define mix(a,b,c) \ 669 { \ 670 a -= c; a ^= rot(c, 4); c += b; \ 671 b -= a; b ^= rot(a, 6); a += c; \ 672 c -= b; c ^= rot(b, 8); b += a; \ 673 a -= c; a ^= rot(c,16); c += b; \ 674 b -= a; b ^= rot(a,19); a += c; \ 675 c -= b; c ^= rot(b, 4); b += a; \ 676 } 677 678// From http://www.burtleburtle.net, by Bob Jenkins. 679#define final(a,b,c) \ 680 { \ 681 c ^= b; c -= rot(b,14); \ 682 a ^= c; a -= rot(c,11); \ 683 b ^= a; b -= rot(a,25); \ 684 c ^= b; c -= rot(b,16); \ 685 a ^= c; a -= rot(c,4); \ 686 b ^= a; b -= rot(a,14); \ 687 c ^= b; c -= rot(b,24); \ 688 } 689 690// hashword() was adapted from http://www.burtleburtle.net, by Bob 691// Jenkins. k is a pointer to an array of uint32_t values; length is 692// the length of the key, in 32-bit chunks. This version only handles 693// keys that are a multiple of 32 bits in size. 694static inline uint32_t hashword(const uint64_t *k64, size_t length) 695{ 696 const uint32_t *k = reinterpret_cast<const uint32_t *>(k64); 697 uint32_t a,b,c; 698 699 /* Set up the internal state */ 700 a = b = c = 0xdeadbeef + (((uint32_t)length)<<2); 701 702 /*------------------------------------------------- handle most of the key */ 703 while (length > 3) { 704 a += k[0]; 705 b += k[1]; 706 c += k[2]; 707 mix(a,b,c); 708 length -= 3; 709 k += 3; 710 } 711 712 /*------------------------------------------- handle the last 3 uint32_t's */ 713 switch (length) { /* all the case statements fall through */ 714 case 3 : c+=k[2]; 715 case 2 : b+=k[1]; 716 case 1 : a+=k[0]; 717 final(a,b,c); 718 case 0: /* case 0: nothing left to add */ 719 break; 720 } 721 /*------------------------------------------------------ report the result */ 722 return c; 723} 724 725// hashword8() was adapted from http://www.burtleburtle.net, by Bob 726// Jenkins. This computes a 32-bit hash from one 64-bit word. When 727// targeting x86 (32 or 64 bit), both LLVM and GCC compile this 728// function into about 35 instructions when inlined. 729static inline uint32_t hashword8(const uint64_t k64) 730{ 731 uint32_t a,b,c; 732 a = b = c = 0xdeadbeef + 4; 733 b += k64 >> 32; 734 a += k64 & 0xffffffff; 735 final(a,b,c); 736 return c; 737} 738#undef final 739#undef mix 740#undef rot 741 742uint64_t APInt::getHashValue() const { 743 uint64_t hash; 744 if (isSingleWord()) 745 hash = hashword8(VAL); 746 else 747 hash = hashword(pVal, getNumWords()*2); 748 return hash; 749} 750 751/// HiBits - This function returns the high "numBits" bits of this APInt. 752APInt APInt::getHiBits(unsigned numBits) const { 753 return APIntOps::lshr(*this, BitWidth - numBits); 754} 755 756/// LoBits - This function returns the low "numBits" bits of this APInt. 757APInt APInt::getLoBits(unsigned numBits) const { 758 return APIntOps::lshr(APIntOps::shl(*this, BitWidth - numBits), 759 BitWidth - numBits); 760} 761 762unsigned APInt::countLeadingZerosSlowCase() const { 763 // Treat the most significand word differently because it might have 764 // meaningless bits set beyond the precision. 765 unsigned BitsInMSW = BitWidth % APINT_BITS_PER_WORD; 766 integerPart MSWMask; 767 if (BitsInMSW) MSWMask = (integerPart(1) << BitsInMSW) - 1; 768 else { 769 MSWMask = ~integerPart(0); 770 BitsInMSW = APINT_BITS_PER_WORD; 771 } 772 773 unsigned i = getNumWords(); 774 integerPart MSW = pVal[i-1] & MSWMask; 775 if (MSW) 776 return CountLeadingZeros_64(MSW) - (APINT_BITS_PER_WORD - BitsInMSW); 777 778 unsigned Count = BitsInMSW; 779 for (--i; i > 0u; --i) { 780 if (pVal[i-1] == 0) 781 Count += APINT_BITS_PER_WORD; 782 else { 783 Count += CountLeadingZeros_64(pVal[i-1]); 784 break; 785 } 786 } 787 return Count; 788} 789 790static unsigned countLeadingOnes_64(uint64_t V, unsigned skip) { 791 unsigned Count = 0; 792 if (skip) 793 V <<= skip; 794 while (V && (V & (1ULL << 63))) { 795 Count++; 796 V <<= 1; 797 } 798 return Count; 799} 800 801unsigned APInt::countLeadingOnes() const { 802 if (isSingleWord()) 803 return countLeadingOnes_64(VAL, APINT_BITS_PER_WORD - BitWidth); 804 805 unsigned highWordBits = BitWidth % APINT_BITS_PER_WORD; 806 unsigned shift; 807 if (!highWordBits) { 808 highWordBits = APINT_BITS_PER_WORD; 809 shift = 0; 810 } else { 811 shift = APINT_BITS_PER_WORD - highWordBits; 812 } 813 int i = getNumWords() - 1; 814 unsigned Count = countLeadingOnes_64(pVal[i], shift); 815 if (Count == highWordBits) { 816 for (i--; i >= 0; --i) { 817 if (pVal[i] == -1ULL) 818 Count += APINT_BITS_PER_WORD; 819 else { 820 Count += countLeadingOnes_64(pVal[i], 0); 821 break; 822 } 823 } 824 } 825 return Count; 826} 827 828unsigned APInt::countTrailingZeros() const { 829 if (isSingleWord()) 830 return std::min(unsigned(CountTrailingZeros_64(VAL)), BitWidth); 831 unsigned Count = 0; 832 unsigned i = 0; 833 for (; i < getNumWords() && pVal[i] == 0; ++i) 834 Count += APINT_BITS_PER_WORD; 835 if (i < getNumWords()) 836 Count += CountTrailingZeros_64(pVal[i]); 837 return std::min(Count, BitWidth); 838} 839 840unsigned APInt::countTrailingOnesSlowCase() const { 841 unsigned Count = 0; 842 unsigned i = 0; 843 for (; i < getNumWords() && pVal[i] == -1ULL; ++i) 844 Count += APINT_BITS_PER_WORD; 845 if (i < getNumWords()) 846 Count += CountTrailingOnes_64(pVal[i]); 847 return std::min(Count, BitWidth); 848} 849 850unsigned APInt::countPopulationSlowCase() const { 851 unsigned Count = 0; 852 for (unsigned i = 0; i < getNumWords(); ++i) 853 Count += CountPopulation_64(pVal[i]); 854 return Count; 855} 856 857APInt APInt::byteSwap() const { 858 assert(BitWidth >= 16 && BitWidth % 16 == 0 && "Cannot byteswap!"); 859 if (BitWidth == 16) 860 return APInt(BitWidth, ByteSwap_16(uint16_t(VAL))); 861 else if (BitWidth == 32) 862 return APInt(BitWidth, ByteSwap_32(unsigned(VAL))); 863 else if (BitWidth == 48) { 864 unsigned Tmp1 = unsigned(VAL >> 16); 865 Tmp1 = ByteSwap_32(Tmp1); 866 uint16_t Tmp2 = uint16_t(VAL); 867 Tmp2 = ByteSwap_16(Tmp2); 868 return APInt(BitWidth, (uint64_t(Tmp2) << 32) | Tmp1); 869 } else if (BitWidth == 64) 870 return APInt(BitWidth, ByteSwap_64(VAL)); 871 else { 872 APInt Result(BitWidth, 0); 873 char *pByte = (char*)Result.pVal; 874 for (unsigned i = 0; i < BitWidth / APINT_WORD_SIZE / 2; ++i) { 875 char Tmp = pByte[i]; 876 pByte[i] = pByte[BitWidth / APINT_WORD_SIZE - 1 - i]; 877 pByte[BitWidth / APINT_WORD_SIZE - i - 1] = Tmp; 878 } 879 return Result; 880 } 881} 882 883APInt llvm::APIntOps::GreatestCommonDivisor(const APInt& API1, 884 const APInt& API2) { 885 APInt A = API1, B = API2; 886 while (!!B) { 887 APInt T = B; 888 B = APIntOps::urem(A, B); 889 A = T; 890 } 891 return A; 892} 893 894APInt llvm::APIntOps::RoundDoubleToAPInt(double Double, unsigned width) { 895 union { 896 double D; 897 uint64_t I; 898 } T; 899 T.D = Double; 900 901 // Get the sign bit from the highest order bit 902 bool isNeg = T.I >> 63; 903 904 // Get the 11-bit exponent and adjust for the 1023 bit bias 905 int64_t exp = ((T.I >> 52) & 0x7ff) - 1023; 906 907 // If the exponent is negative, the value is < 0 so just return 0. 908 if (exp < 0) 909 return APInt(width, 0u); 910 911 // Extract the mantissa by clearing the top 12 bits (sign + exponent). 912 uint64_t mantissa = (T.I & (~0ULL >> 12)) | 1ULL << 52; 913 914 // If the exponent doesn't shift all bits out of the mantissa 915 if (exp < 52) 916 return isNeg ? -APInt(width, mantissa >> (52 - exp)) : 917 APInt(width, mantissa >> (52 - exp)); 918 919 // If the client didn't provide enough bits for us to shift the mantissa into 920 // then the result is undefined, just return 0 921 if (width <= exp - 52) 922 return APInt(width, 0); 923 924 // Otherwise, we have to shift the mantissa bits up to the right location 925 APInt Tmp(width, mantissa); 926 Tmp = Tmp.shl((unsigned)exp - 52); 927 return isNeg ? -Tmp : Tmp; 928} 929 930/// RoundToDouble - This function converts this APInt to a double. 931/// The layout for double is as following (IEEE Standard 754): 932/// -------------------------------------- 933/// | Sign Exponent Fraction Bias | 934/// |-------------------------------------- | 935/// | 1[63] 11[62-52] 52[51-00] 1023 | 936/// -------------------------------------- 937double APInt::roundToDouble(bool isSigned) const { 938 939 // Handle the simple case where the value is contained in one uint64_t. 940 // It is wrong to optimize getWord(0) to VAL; there might be more than one word. 941 if (isSingleWord() || getActiveBits() <= APINT_BITS_PER_WORD) { 942 if (isSigned) { 943 int64_t sext = (int64_t(getWord(0)) << (64-BitWidth)) >> (64-BitWidth); 944 return double(sext); 945 } else 946 return double(getWord(0)); 947 } 948 949 // Determine if the value is negative. 950 bool isNeg = isSigned ? (*this)[BitWidth-1] : false; 951 952 // Construct the absolute value if we're negative. 953 APInt Tmp(isNeg ? -(*this) : (*this)); 954 955 // Figure out how many bits we're using. 956 unsigned n = Tmp.getActiveBits(); 957 958 // The exponent (without bias normalization) is just the number of bits 959 // we are using. Note that the sign bit is gone since we constructed the 960 // absolute value. 961 uint64_t exp = n; 962 963 // Return infinity for exponent overflow 964 if (exp > 1023) { 965 if (!isSigned || !isNeg) 966 return std::numeric_limits<double>::infinity(); 967 else 968 return -std::numeric_limits<double>::infinity(); 969 } 970 exp += 1023; // Increment for 1023 bias 971 972 // Number of bits in mantissa is 52. To obtain the mantissa value, we must 973 // extract the high 52 bits from the correct words in pVal. 974 uint64_t mantissa; 975 unsigned hiWord = whichWord(n-1); 976 if (hiWord == 0) { 977 mantissa = Tmp.pVal[0]; 978 if (n > 52) 979 mantissa >>= n - 52; // shift down, we want the top 52 bits. 980 } else { 981 assert(hiWord > 0 && "huh?"); 982 uint64_t hibits = Tmp.pVal[hiWord] << (52 - n % APINT_BITS_PER_WORD); 983 uint64_t lobits = Tmp.pVal[hiWord-1] >> (11 + n % APINT_BITS_PER_WORD); 984 mantissa = hibits | lobits; 985 } 986 987 // The leading bit of mantissa is implicit, so get rid of it. 988 uint64_t sign = isNeg ? (1ULL << (APINT_BITS_PER_WORD - 1)) : 0; 989 union { 990 double D; 991 uint64_t I; 992 } T; 993 T.I = sign | (exp << 52) | mantissa; 994 return T.D; 995} 996 997// Truncate to new width. 998APInt APInt::trunc(unsigned width) const { 999 assert(width < BitWidth && "Invalid APInt Truncate request"); 1000 assert(width && "Can't truncate to 0 bits"); 1001 1002 if (width <= APINT_BITS_PER_WORD) 1003 return APInt(width, getRawData()[0]); 1004 1005 APInt Result(getMemory(getNumWords(width)), width); 1006 1007 // Copy full words. 1008 unsigned i; 1009 for (i = 0; i != width / APINT_BITS_PER_WORD; i++) 1010 Result.pVal[i] = pVal[i]; 1011 1012 // Truncate and copy any partial word. 1013 unsigned bits = (0 - width) % APINT_BITS_PER_WORD; 1014 if (bits != 0) 1015 Result.pVal[i] = pVal[i] << bits >> bits; 1016 1017 return Result; 1018} 1019 1020// Sign extend to a new width. 1021APInt APInt::sext(unsigned width) const { 1022 assert(width > BitWidth && "Invalid APInt SignExtend request"); 1023 1024 if (width <= APINT_BITS_PER_WORD) { 1025 uint64_t val = VAL << (APINT_BITS_PER_WORD - BitWidth); 1026 val = (int64_t)val >> (width - BitWidth); 1027 return APInt(width, val >> (APINT_BITS_PER_WORD - width)); 1028 } 1029 1030 APInt Result(getMemory(getNumWords(width)), width); 1031 1032 // Copy full words. 1033 unsigned i; 1034 uint64_t word = 0; 1035 for (i = 0; i != BitWidth / APINT_BITS_PER_WORD; i++) { 1036 word = getRawData()[i]; 1037 Result.pVal[i] = word; 1038 } 1039 1040 // Read and sign-extend any partial word. 1041 unsigned bits = (0 - BitWidth) % APINT_BITS_PER_WORD; 1042 if (bits != 0) 1043 word = (int64_t)getRawData()[i] << bits >> bits; 1044 else 1045 word = (int64_t)word >> (APINT_BITS_PER_WORD - 1); 1046 1047 // Write remaining full words. 1048 for (; i != width / APINT_BITS_PER_WORD; i++) { 1049 Result.pVal[i] = word; 1050 word = (int64_t)word >> (APINT_BITS_PER_WORD - 1); 1051 } 1052 1053 // Write any partial word. 1054 bits = (0 - width) % APINT_BITS_PER_WORD; 1055 if (bits != 0) 1056 Result.pVal[i] = word << bits >> bits; 1057 1058 return Result; 1059} 1060 1061// Zero extend to a new width. 1062APInt APInt::zext(unsigned width) const { 1063 assert(width > BitWidth && "Invalid APInt ZeroExtend request"); 1064 1065 if (width <= APINT_BITS_PER_WORD) 1066 return APInt(width, VAL); 1067 1068 APInt Result(getMemory(getNumWords(width)), width); 1069 1070 // Copy words. 1071 unsigned i; 1072 for (i = 0; i != getNumWords(); i++) 1073 Result.pVal[i] = getRawData()[i]; 1074 1075 // Zero remaining words. 1076 memset(&Result.pVal[i], 0, (Result.getNumWords() - i) * APINT_WORD_SIZE); 1077 1078 return Result; 1079} 1080 1081APInt APInt::zextOrTrunc(unsigned width) const { 1082 if (BitWidth < width) 1083 return zext(width); 1084 if (BitWidth > width) 1085 return trunc(width); 1086 return *this; 1087} 1088 1089APInt APInt::sextOrTrunc(unsigned width) const { 1090 if (BitWidth < width) 1091 return sext(width); 1092 if (BitWidth > width) 1093 return trunc(width); 1094 return *this; 1095} 1096 1097/// Arithmetic right-shift this APInt by shiftAmt. 1098/// @brief Arithmetic right-shift function. 1099APInt APInt::ashr(const APInt &shiftAmt) const { 1100 return ashr((unsigned)shiftAmt.getLimitedValue(BitWidth)); 1101} 1102 1103/// Arithmetic right-shift this APInt by shiftAmt. 1104/// @brief Arithmetic right-shift function. 1105APInt APInt::ashr(unsigned shiftAmt) const { 1106 assert(shiftAmt <= BitWidth && "Invalid shift amount"); 1107 // Handle a degenerate case 1108 if (shiftAmt == 0) 1109 return *this; 1110 1111 // Handle single word shifts with built-in ashr 1112 if (isSingleWord()) { 1113 if (shiftAmt == BitWidth) 1114 return APInt(BitWidth, 0); // undefined 1115 else { 1116 unsigned SignBit = APINT_BITS_PER_WORD - BitWidth; 1117 return APInt(BitWidth, 1118 (((int64_t(VAL) << SignBit) >> SignBit) >> shiftAmt)); 1119 } 1120 } 1121 1122 // If all the bits were shifted out, the result is, technically, undefined. 1123 // We return -1 if it was negative, 0 otherwise. We check this early to avoid 1124 // issues in the algorithm below. 1125 if (shiftAmt == BitWidth) { 1126 if (isNegative()) 1127 return APInt(BitWidth, -1ULL, true); 1128 else 1129 return APInt(BitWidth, 0); 1130 } 1131 1132 // Create some space for the result. 1133 uint64_t * val = new uint64_t[getNumWords()]; 1134 1135 // Compute some values needed by the following shift algorithms 1136 unsigned wordShift = shiftAmt % APINT_BITS_PER_WORD; // bits to shift per word 1137 unsigned offset = shiftAmt / APINT_BITS_PER_WORD; // word offset for shift 1138 unsigned breakWord = getNumWords() - 1 - offset; // last word affected 1139 unsigned bitsInWord = whichBit(BitWidth); // how many bits in last word? 1140 if (bitsInWord == 0) 1141 bitsInWord = APINT_BITS_PER_WORD; 1142 1143 // If we are shifting whole words, just move whole words 1144 if (wordShift == 0) { 1145 // Move the words containing significant bits 1146 for (unsigned i = 0; i <= breakWord; ++i) 1147 val[i] = pVal[i+offset]; // move whole word 1148 1149 // Adjust the top significant word for sign bit fill, if negative 1150 if (isNegative()) 1151 if (bitsInWord < APINT_BITS_PER_WORD) 1152 val[breakWord] |= ~0ULL << bitsInWord; // set high bits 1153 } else { 1154 // Shift the low order words 1155 for (unsigned i = 0; i < breakWord; ++i) { 1156 // This combines the shifted corresponding word with the low bits from 1157 // the next word (shifted into this word's high bits). 1158 val[i] = (pVal[i+offset] >> wordShift) | 1159 (pVal[i+offset+1] << (APINT_BITS_PER_WORD - wordShift)); 1160 } 1161 1162 // Shift the break word. In this case there are no bits from the next word 1163 // to include in this word. 1164 val[breakWord] = pVal[breakWord+offset] >> wordShift; 1165 1166 // Deal with sign extenstion in the break word, and possibly the word before 1167 // it. 1168 if (isNegative()) { 1169 if (wordShift > bitsInWord) { 1170 if (breakWord > 0) 1171 val[breakWord-1] |= 1172 ~0ULL << (APINT_BITS_PER_WORD - (wordShift - bitsInWord)); 1173 val[breakWord] |= ~0ULL; 1174 } else 1175 val[breakWord] |= (~0ULL << (bitsInWord - wordShift)); 1176 } 1177 } 1178 1179 // Remaining words are 0 or -1, just assign them. 1180 uint64_t fillValue = (isNegative() ? -1ULL : 0); 1181 for (unsigned i = breakWord+1; i < getNumWords(); ++i) 1182 val[i] = fillValue; 1183 return APInt(val, BitWidth).clearUnusedBits(); 1184} 1185 1186/// Logical right-shift this APInt by shiftAmt. 1187/// @brief Logical right-shift function. 1188APInt APInt::lshr(const APInt &shiftAmt) const { 1189 return lshr((unsigned)shiftAmt.getLimitedValue(BitWidth)); 1190} 1191 1192/// Logical right-shift this APInt by shiftAmt. 1193/// @brief Logical right-shift function. 1194APInt APInt::lshr(unsigned shiftAmt) const { 1195 if (isSingleWord()) { 1196 if (shiftAmt == BitWidth) 1197 return APInt(BitWidth, 0); 1198 else 1199 return APInt(BitWidth, this->VAL >> shiftAmt); 1200 } 1201 1202 // If all the bits were shifted out, the result is 0. This avoids issues 1203 // with shifting by the size of the integer type, which produces undefined 1204 // results. We define these "undefined results" to always be 0. 1205 if (shiftAmt == BitWidth) 1206 return APInt(BitWidth, 0); 1207 1208 // If none of the bits are shifted out, the result is *this. This avoids 1209 // issues with shifting by the size of the integer type, which produces 1210 // undefined results in the code below. This is also an optimization. 1211 if (shiftAmt == 0) 1212 return *this; 1213 1214 // Create some space for the result. 1215 uint64_t * val = new uint64_t[getNumWords()]; 1216 1217 // If we are shifting less than a word, compute the shift with a simple carry 1218 if (shiftAmt < APINT_BITS_PER_WORD) { 1219 uint64_t carry = 0; 1220 for (int i = getNumWords()-1; i >= 0; --i) { 1221 val[i] = (pVal[i] >> shiftAmt) | carry; 1222 carry = pVal[i] << (APINT_BITS_PER_WORD - shiftAmt); 1223 } 1224 return APInt(val, BitWidth).clearUnusedBits(); 1225 } 1226 1227 // Compute some values needed by the remaining shift algorithms 1228 unsigned wordShift = shiftAmt % APINT_BITS_PER_WORD; 1229 unsigned offset = shiftAmt / APINT_BITS_PER_WORD; 1230 1231 // If we are shifting whole words, just move whole words 1232 if (wordShift == 0) { 1233 for (unsigned i = 0; i < getNumWords() - offset; ++i) 1234 val[i] = pVal[i+offset]; 1235 for (unsigned i = getNumWords()-offset; i < getNumWords(); i++) 1236 val[i] = 0; 1237 return APInt(val,BitWidth).clearUnusedBits(); 1238 } 1239 1240 // Shift the low order words 1241 unsigned breakWord = getNumWords() - offset -1; 1242 for (unsigned i = 0; i < breakWord; ++i) 1243 val[i] = (pVal[i+offset] >> wordShift) | 1244 (pVal[i+offset+1] << (APINT_BITS_PER_WORD - wordShift)); 1245 // Shift the break word. 1246 val[breakWord] = pVal[breakWord+offset] >> wordShift; 1247 1248 // Remaining words are 0 1249 for (unsigned i = breakWord+1; i < getNumWords(); ++i) 1250 val[i] = 0; 1251 return APInt(val, BitWidth).clearUnusedBits(); 1252} 1253 1254/// Left-shift this APInt by shiftAmt. 1255/// @brief Left-shift function. 1256APInt APInt::shl(const APInt &shiftAmt) const { 1257 // It's undefined behavior in C to shift by BitWidth or greater. 1258 return shl((unsigned)shiftAmt.getLimitedValue(BitWidth)); 1259} 1260 1261APInt APInt::shlSlowCase(unsigned shiftAmt) const { 1262 // If all the bits were shifted out, the result is 0. This avoids issues 1263 // with shifting by the size of the integer type, which produces undefined 1264 // results. We define these "undefined results" to always be 0. 1265 if (shiftAmt == BitWidth) 1266 return APInt(BitWidth, 0); 1267 1268 // If none of the bits are shifted out, the result is *this. This avoids a 1269 // lshr by the words size in the loop below which can produce incorrect 1270 // results. It also avoids the expensive computation below for a common case. 1271 if (shiftAmt == 0) 1272 return *this; 1273 1274 // Create some space for the result. 1275 uint64_t * val = new uint64_t[getNumWords()]; 1276 1277 // If we are shifting less than a word, do it the easy way 1278 if (shiftAmt < APINT_BITS_PER_WORD) { 1279 uint64_t carry = 0; 1280 for (unsigned i = 0; i < getNumWords(); i++) { 1281 val[i] = pVal[i] << shiftAmt | carry; 1282 carry = pVal[i] >> (APINT_BITS_PER_WORD - shiftAmt); 1283 } 1284 return APInt(val, BitWidth).clearUnusedBits(); 1285 } 1286 1287 // Compute some values needed by the remaining shift algorithms 1288 unsigned wordShift = shiftAmt % APINT_BITS_PER_WORD; 1289 unsigned offset = shiftAmt / APINT_BITS_PER_WORD; 1290 1291 // If we are shifting whole words, just move whole words 1292 if (wordShift == 0) { 1293 for (unsigned i = 0; i < offset; i++) 1294 val[i] = 0; 1295 for (unsigned i = offset; i < getNumWords(); i++) 1296 val[i] = pVal[i-offset]; 1297 return APInt(val,BitWidth).clearUnusedBits(); 1298 } 1299 1300 // Copy whole words from this to Result. 1301 unsigned i = getNumWords() - 1; 1302 for (; i > offset; --i) 1303 val[i] = pVal[i-offset] << wordShift | 1304 pVal[i-offset-1] >> (APINT_BITS_PER_WORD - wordShift); 1305 val[offset] = pVal[0] << wordShift; 1306 for (i = 0; i < offset; ++i) 1307 val[i] = 0; 1308 return APInt(val, BitWidth).clearUnusedBits(); 1309} 1310 1311APInt APInt::rotl(const APInt &rotateAmt) const { 1312 return rotl((unsigned)rotateAmt.getLimitedValue(BitWidth)); 1313} 1314 1315APInt APInt::rotl(unsigned rotateAmt) const { 1316 if (rotateAmt == 0) 1317 return *this; 1318 // Don't get too fancy, just use existing shift/or facilities 1319 APInt hi(*this); 1320 APInt lo(*this); 1321 hi.shl(rotateAmt); 1322 lo.lshr(BitWidth - rotateAmt); 1323 return hi | lo; 1324} 1325 1326APInt APInt::rotr(const APInt &rotateAmt) const { 1327 return rotr((unsigned)rotateAmt.getLimitedValue(BitWidth)); 1328} 1329 1330APInt APInt::rotr(unsigned rotateAmt) const { 1331 if (rotateAmt == 0) 1332 return *this; 1333 // Don't get too fancy, just use existing shift/or facilities 1334 APInt hi(*this); 1335 APInt lo(*this); 1336 lo.lshr(rotateAmt); 1337 hi.shl(BitWidth - rotateAmt); 1338 return hi | lo; 1339} 1340 1341// Square Root - this method computes and returns the square root of "this". 1342// Three mechanisms are used for computation. For small values (<= 5 bits), 1343// a table lookup is done. This gets some performance for common cases. For 1344// values using less than 52 bits, the value is converted to double and then 1345// the libc sqrt function is called. The result is rounded and then converted 1346// back to a uint64_t which is then used to construct the result. Finally, 1347// the Babylonian method for computing square roots is used. 1348APInt APInt::sqrt() const { 1349 1350 // Determine the magnitude of the value. 1351 unsigned magnitude = getActiveBits(); 1352 1353 // Use a fast table for some small values. This also gets rid of some 1354 // rounding errors in libc sqrt for small values. 1355 if (magnitude <= 5) { 1356 static const uint8_t results[32] = { 1357 /* 0 */ 0, 1358 /* 1- 2 */ 1, 1, 1359 /* 3- 6 */ 2, 2, 2, 2, 1360 /* 7-12 */ 3, 3, 3, 3, 3, 3, 1361 /* 13-20 */ 4, 4, 4, 4, 4, 4, 4, 4, 1362 /* 21-30 */ 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 1363 /* 31 */ 6 1364 }; 1365 return APInt(BitWidth, results[ (isSingleWord() ? VAL : pVal[0]) ]); 1366 } 1367 1368 // If the magnitude of the value fits in less than 52 bits (the precision of 1369 // an IEEE double precision floating point value), then we can use the 1370 // libc sqrt function which will probably use a hardware sqrt computation. 1371 // This should be faster than the algorithm below. 1372 if (magnitude < 52) { 1373#if HAVE_ROUND 1374 return APInt(BitWidth, 1375 uint64_t(::round(::sqrt(double(isSingleWord()?VAL:pVal[0]))))); 1376#else 1377 return APInt(BitWidth, 1378 uint64_t(::sqrt(double(isSingleWord()?VAL:pVal[0]))) + 0.5); 1379#endif 1380 } 1381 1382 // Okay, all the short cuts are exhausted. We must compute it. The following 1383 // is a classical Babylonian method for computing the square root. This code 1384 // was adapted to APINt from a wikipedia article on such computations. 1385 // See http://www.wikipedia.org/ and go to the page named 1386 // Calculate_an_integer_square_root. 1387 unsigned nbits = BitWidth, i = 4; 1388 APInt testy(BitWidth, 16); 1389 APInt x_old(BitWidth, 1); 1390 APInt x_new(BitWidth, 0); 1391 APInt two(BitWidth, 2); 1392 1393 // Select a good starting value using binary logarithms. 1394 for (;; i += 2, testy = testy.shl(2)) 1395 if (i >= nbits || this->ule(testy)) { 1396 x_old = x_old.shl(i / 2); 1397 break; 1398 } 1399 1400 // Use the Babylonian method to arrive at the integer square root: 1401 for (;;) { 1402 x_new = (this->udiv(x_old) + x_old).udiv(two); 1403 if (x_old.ule(x_new)) 1404 break; 1405 x_old = x_new; 1406 } 1407 1408 // Make sure we return the closest approximation 1409 // NOTE: The rounding calculation below is correct. It will produce an 1410 // off-by-one discrepancy with results from pari/gp. That discrepancy has been 1411 // determined to be a rounding issue with pari/gp as it begins to use a 1412 // floating point representation after 192 bits. There are no discrepancies 1413 // between this algorithm and pari/gp for bit widths < 192 bits. 1414 APInt square(x_old * x_old); 1415 APInt nextSquare((x_old + 1) * (x_old +1)); 1416 if (this->ult(square)) 1417 return x_old; 1418 else if (this->ule(nextSquare)) { 1419 APInt midpoint((nextSquare - square).udiv(two)); 1420 APInt offset(*this - square); 1421 if (offset.ult(midpoint)) 1422 return x_old; 1423 else 1424 return x_old + 1; 1425 } else 1426 llvm_unreachable("Error in APInt::sqrt computation"); 1427 return x_old + 1; 1428} 1429 1430/// Computes the multiplicative inverse of this APInt for a given modulo. The 1431/// iterative extended Euclidean algorithm is used to solve for this value, 1432/// however we simplify it to speed up calculating only the inverse, and take 1433/// advantage of div+rem calculations. We also use some tricks to avoid copying 1434/// (potentially large) APInts around. 1435APInt APInt::multiplicativeInverse(const APInt& modulo) const { 1436 assert(ult(modulo) && "This APInt must be smaller than the modulo"); 1437 1438 // Using the properties listed at the following web page (accessed 06/21/08): 1439 // http://www.numbertheory.org/php/euclid.html 1440 // (especially the properties numbered 3, 4 and 9) it can be proved that 1441 // BitWidth bits suffice for all the computations in the algorithm implemented 1442 // below. More precisely, this number of bits suffice if the multiplicative 1443 // inverse exists, but may not suffice for the general extended Euclidean 1444 // algorithm. 1445 1446 APInt r[2] = { modulo, *this }; 1447 APInt t[2] = { APInt(BitWidth, 0), APInt(BitWidth, 1) }; 1448 APInt q(BitWidth, 0); 1449 1450 unsigned i; 1451 for (i = 0; r[i^1] != 0; i ^= 1) { 1452 // An overview of the math without the confusing bit-flipping: 1453 // q = r[i-2] / r[i-1] 1454 // r[i] = r[i-2] % r[i-1] 1455 // t[i] = t[i-2] - t[i-1] * q 1456 udivrem(r[i], r[i^1], q, r[i]); 1457 t[i] -= t[i^1] * q; 1458 } 1459 1460 // If this APInt and the modulo are not coprime, there is no multiplicative 1461 // inverse, so return 0. We check this by looking at the next-to-last 1462 // remainder, which is the gcd(*this,modulo) as calculated by the Euclidean 1463 // algorithm. 1464 if (r[i] != 1) 1465 return APInt(BitWidth, 0); 1466 1467 // The next-to-last t is the multiplicative inverse. However, we are 1468 // interested in a positive inverse. Calcuate a positive one from a negative 1469 // one if necessary. A simple addition of the modulo suffices because 1470 // abs(t[i]) is known to be less than *this/2 (see the link above). 1471 return t[i].isNegative() ? t[i] + modulo : t[i]; 1472} 1473 1474/// Calculate the magic numbers required to implement a signed integer division 1475/// by a constant as a sequence of multiplies, adds and shifts. Requires that 1476/// the divisor not be 0, 1, or -1. Taken from "Hacker's Delight", Henry S. 1477/// Warren, Jr., chapter 10. 1478APInt::ms APInt::magic() const { 1479 const APInt& d = *this; 1480 unsigned p; 1481 APInt ad, anc, delta, q1, r1, q2, r2, t; 1482 APInt signedMin = APInt::getSignedMinValue(d.getBitWidth()); 1483 struct ms mag; 1484 1485 ad = d.abs(); 1486 t = signedMin + (d.lshr(d.getBitWidth() - 1)); 1487 anc = t - 1 - t.urem(ad); // absolute value of nc 1488 p = d.getBitWidth() - 1; // initialize p 1489 q1 = signedMin.udiv(anc); // initialize q1 = 2p/abs(nc) 1490 r1 = signedMin - q1*anc; // initialize r1 = rem(2p,abs(nc)) 1491 q2 = signedMin.udiv(ad); // initialize q2 = 2p/abs(d) 1492 r2 = signedMin - q2*ad; // initialize r2 = rem(2p,abs(d)) 1493 do { 1494 p = p + 1; 1495 q1 = q1<<1; // update q1 = 2p/abs(nc) 1496 r1 = r1<<1; // update r1 = rem(2p/abs(nc)) 1497 if (r1.uge(anc)) { // must be unsigned comparison 1498 q1 = q1 + 1; 1499 r1 = r1 - anc; 1500 } 1501 q2 = q2<<1; // update q2 = 2p/abs(d) 1502 r2 = r2<<1; // update r2 = rem(2p/abs(d)) 1503 if (r2.uge(ad)) { // must be unsigned comparison 1504 q2 = q2 + 1; 1505 r2 = r2 - ad; 1506 } 1507 delta = ad - r2; 1508 } while (q1.ult(delta) || (q1 == delta && r1 == 0)); 1509 1510 mag.m = q2 + 1; 1511 if (d.isNegative()) mag.m = -mag.m; // resulting magic number 1512 mag.s = p - d.getBitWidth(); // resulting shift 1513 return mag; 1514} 1515 1516/// Calculate the magic numbers required to implement an unsigned integer 1517/// division by a constant as a sequence of multiplies, adds and shifts. 1518/// Requires that the divisor not be 0. Taken from "Hacker's Delight", Henry 1519/// S. Warren, Jr., chapter 10. 1520/// LeadingZeros can be used to simplify the calculation if the upper bits 1521/// of the divided value are known zero. 1522APInt::mu APInt::magicu(unsigned LeadingZeros) const { 1523 const APInt& d = *this; 1524 unsigned p; 1525 APInt nc, delta, q1, r1, q2, r2; 1526 struct mu magu; 1527 magu.a = 0; // initialize "add" indicator 1528 APInt allOnes = APInt::getAllOnesValue(d.getBitWidth()).lshr(LeadingZeros); 1529 APInt signedMin = APInt::getSignedMinValue(d.getBitWidth()); 1530 APInt signedMax = APInt::getSignedMaxValue(d.getBitWidth()); 1531 1532 nc = allOnes - (-d).urem(d); 1533 p = d.getBitWidth() - 1; // initialize p 1534 q1 = signedMin.udiv(nc); // initialize q1 = 2p/nc 1535 r1 = signedMin - q1*nc; // initialize r1 = rem(2p,nc) 1536 q2 = signedMax.udiv(d); // initialize q2 = (2p-1)/d 1537 r2 = signedMax - q2*d; // initialize r2 = rem((2p-1),d) 1538 do { 1539 p = p + 1; 1540 if (r1.uge(nc - r1)) { 1541 q1 = q1 + q1 + 1; // update q1 1542 r1 = r1 + r1 - nc; // update r1 1543 } 1544 else { 1545 q1 = q1+q1; // update q1 1546 r1 = r1+r1; // update r1 1547 } 1548 if ((r2 + 1).uge(d - r2)) { 1549 if (q2.uge(signedMax)) magu.a = 1; 1550 q2 = q2+q2 + 1; // update q2 1551 r2 = r2+r2 + 1 - d; // update r2 1552 } 1553 else { 1554 if (q2.uge(signedMin)) magu.a = 1; 1555 q2 = q2+q2; // update q2 1556 r2 = r2+r2 + 1; // update r2 1557 } 1558 delta = d - 1 - r2; 1559 } while (p < d.getBitWidth()*2 && 1560 (q1.ult(delta) || (q1 == delta && r1 == 0))); 1561 magu.m = q2 + 1; // resulting magic number 1562 magu.s = p - d.getBitWidth(); // resulting shift 1563 return magu; 1564} 1565 1566/// Implementation of Knuth's Algorithm D (Division of nonnegative integers) 1567/// from "Art of Computer Programming, Volume 2", section 4.3.1, p. 272. The 1568/// variables here have the same names as in the algorithm. Comments explain 1569/// the algorithm and any deviation from it. 1570static void KnuthDiv(unsigned *u, unsigned *v, unsigned *q, unsigned* r, 1571 unsigned m, unsigned n) { 1572 assert(u && "Must provide dividend"); 1573 assert(v && "Must provide divisor"); 1574 assert(q && "Must provide quotient"); 1575 assert(u != v && u != q && v != q && "Must us different memory"); 1576 assert(n>1 && "n must be > 1"); 1577 1578 // Knuth uses the value b as the base of the number system. In our case b 1579 // is 2^31 so we just set it to -1u. 1580 uint64_t b = uint64_t(1) << 32; 1581 1582#if 0 1583 DEBUG(dbgs() << "KnuthDiv: m=" << m << " n=" << n << '\n'); 1584 DEBUG(dbgs() << "KnuthDiv: original:"); 1585 DEBUG(for (int i = m+n; i >=0; i--) dbgs() << " " << u[i]); 1586 DEBUG(dbgs() << " by"); 1587 DEBUG(for (int i = n; i >0; i--) dbgs() << " " << v[i-1]); 1588 DEBUG(dbgs() << '\n'); 1589#endif 1590 // D1. [Normalize.] Set d = b / (v[n-1] + 1) and multiply all the digits of 1591 // u and v by d. Note that we have taken Knuth's advice here to use a power 1592 // of 2 value for d such that d * v[n-1] >= b/2 (b is the base). A power of 1593 // 2 allows us to shift instead of multiply and it is easy to determine the 1594 // shift amount from the leading zeros. We are basically normalizing the u 1595 // and v so that its high bits are shifted to the top of v's range without 1596 // overflow. Note that this can require an extra word in u so that u must 1597 // be of length m+n+1. 1598 unsigned shift = CountLeadingZeros_32(v[n-1]); 1599 unsigned v_carry = 0; 1600 unsigned u_carry = 0; 1601 if (shift) { 1602 for (unsigned i = 0; i < m+n; ++i) { 1603 unsigned u_tmp = u[i] >> (32 - shift); 1604 u[i] = (u[i] << shift) | u_carry; 1605 u_carry = u_tmp; 1606 } 1607 for (unsigned i = 0; i < n; ++i) { 1608 unsigned v_tmp = v[i] >> (32 - shift); 1609 v[i] = (v[i] << shift) | v_carry; 1610 v_carry = v_tmp; 1611 } 1612 } 1613 u[m+n] = u_carry; 1614#if 0 1615 DEBUG(dbgs() << "KnuthDiv: normal:"); 1616 DEBUG(for (int i = m+n; i >=0; i--) dbgs() << " " << u[i]); 1617 DEBUG(dbgs() << " by"); 1618 DEBUG(for (int i = n; i >0; i--) dbgs() << " " << v[i-1]); 1619 DEBUG(dbgs() << '\n'); 1620#endif 1621 1622 // D2. [Initialize j.] Set j to m. This is the loop counter over the places. 1623 int j = m; 1624 do { 1625 DEBUG(dbgs() << "KnuthDiv: quotient digit #" << j << '\n'); 1626 // D3. [Calculate q'.]. 1627 // Set qp = (u[j+n]*b + u[j+n-1]) / v[n-1]. (qp=qprime=q') 1628 // Set rp = (u[j+n]*b + u[j+n-1]) % v[n-1]. (rp=rprime=r') 1629 // Now test if qp == b or qp*v[n-2] > b*rp + u[j+n-2]; if so, decrease 1630 // qp by 1, inrease rp by v[n-1], and repeat this test if rp < b. The test 1631 // on v[n-2] determines at high speed most of the cases in which the trial 1632 // value qp is one too large, and it eliminates all cases where qp is two 1633 // too large. 1634 uint64_t dividend = ((uint64_t(u[j+n]) << 32) + u[j+n-1]); 1635 DEBUG(dbgs() << "KnuthDiv: dividend == " << dividend << '\n'); 1636 uint64_t qp = dividend / v[n-1]; 1637 uint64_t rp = dividend % v[n-1]; 1638 if (qp == b || qp*v[n-2] > b*rp + u[j+n-2]) { 1639 qp--; 1640 rp += v[n-1]; 1641 if (rp < b && (qp == b || qp*v[n-2] > b*rp + u[j+n-2])) 1642 qp--; 1643 } 1644 DEBUG(dbgs() << "KnuthDiv: qp == " << qp << ", rp == " << rp << '\n'); 1645 1646 // D4. [Multiply and subtract.] Replace (u[j+n]u[j+n-1]...u[j]) with 1647 // (u[j+n]u[j+n-1]..u[j]) - qp * (v[n-1]...v[1]v[0]). This computation 1648 // consists of a simple multiplication by a one-place number, combined with 1649 // a subtraction. 1650 bool isNeg = false; 1651 for (unsigned i = 0; i < n; ++i) { 1652 uint64_t u_tmp = uint64_t(u[j+i]) | (uint64_t(u[j+i+1]) << 32); 1653 uint64_t subtrahend = uint64_t(qp) * uint64_t(v[i]); 1654 bool borrow = subtrahend > u_tmp; 1655 DEBUG(dbgs() << "KnuthDiv: u_tmp == " << u_tmp 1656 << ", subtrahend == " << subtrahend 1657 << ", borrow = " << borrow << '\n'); 1658 1659 uint64_t result = u_tmp - subtrahend; 1660 unsigned k = j + i; 1661 u[k++] = (unsigned)(result & (b-1)); // subtract low word 1662 u[k++] = (unsigned)(result >> 32); // subtract high word 1663 while (borrow && k <= m+n) { // deal with borrow to the left 1664 borrow = u[k] == 0; 1665 u[k]--; 1666 k++; 1667 } 1668 isNeg |= borrow; 1669 DEBUG(dbgs() << "KnuthDiv: u[j+i] == " << u[j+i] << ", u[j+i+1] == " << 1670 u[j+i+1] << '\n'); 1671 } 1672 DEBUG(dbgs() << "KnuthDiv: after subtraction:"); 1673 DEBUG(for (int i = m+n; i >=0; i--) dbgs() << " " << u[i]); 1674 DEBUG(dbgs() << '\n'); 1675 // The digits (u[j+n]...u[j]) should be kept positive; if the result of 1676 // this step is actually negative, (u[j+n]...u[j]) should be left as the 1677 // true value plus b**(n+1), namely as the b's complement of 1678 // the true value, and a "borrow" to the left should be remembered. 1679 // 1680 if (isNeg) { 1681 bool carry = true; // true because b's complement is "complement + 1" 1682 for (unsigned i = 0; i <= m+n; ++i) { 1683 u[i] = ~u[i] + carry; // b's complement 1684 carry = carry && u[i] == 0; 1685 } 1686 } 1687 DEBUG(dbgs() << "KnuthDiv: after complement:"); 1688 DEBUG(for (int i = m+n; i >=0; i--) dbgs() << " " << u[i]); 1689 DEBUG(dbgs() << '\n'); 1690 1691 // D5. [Test remainder.] Set q[j] = qp. If the result of step D4 was 1692 // negative, go to step D6; otherwise go on to step D7. 1693 q[j] = (unsigned)qp; 1694 if (isNeg) { 1695 // D6. [Add back]. The probability that this step is necessary is very 1696 // small, on the order of only 2/b. Make sure that test data accounts for 1697 // this possibility. Decrease q[j] by 1 1698 q[j]--; 1699 // and add (0v[n-1]...v[1]v[0]) to (u[j+n]u[j+n-1]...u[j+1]u[j]). 1700 // A carry will occur to the left of u[j+n], and it should be ignored 1701 // since it cancels with the borrow that occurred in D4. 1702 bool carry = false; 1703 for (unsigned i = 0; i < n; i++) { 1704 unsigned limit = std::min(u[j+i],v[i]); 1705 u[j+i] += v[i] + carry; 1706 carry = u[j+i] < limit || (carry && u[j+i] == limit); 1707 } 1708 u[j+n] += carry; 1709 } 1710 DEBUG(dbgs() << "KnuthDiv: after correction:"); 1711 DEBUG(for (int i = m+n; i >=0; i--) dbgs() <<" " << u[i]); 1712 DEBUG(dbgs() << "\nKnuthDiv: digit result = " << q[j] << '\n'); 1713 1714 // D7. [Loop on j.] Decrease j by one. Now if j >= 0, go back to D3. 1715 } while (--j >= 0); 1716 1717 DEBUG(dbgs() << "KnuthDiv: quotient:"); 1718 DEBUG(for (int i = m; i >=0; i--) dbgs() <<" " << q[i]); 1719 DEBUG(dbgs() << '\n'); 1720 1721 // D8. [Unnormalize]. Now q[...] is the desired quotient, and the desired 1722 // remainder may be obtained by dividing u[...] by d. If r is non-null we 1723 // compute the remainder (urem uses this). 1724 if (r) { 1725 // The value d is expressed by the "shift" value above since we avoided 1726 // multiplication by d by using a shift left. So, all we have to do is 1727 // shift right here. In order to mak 1728 if (shift) { 1729 unsigned carry = 0; 1730 DEBUG(dbgs() << "KnuthDiv: remainder:"); 1731 for (int i = n-1; i >= 0; i--) { 1732 r[i] = (u[i] >> shift) | carry; 1733 carry = u[i] << (32 - shift); 1734 DEBUG(dbgs() << " " << r[i]); 1735 } 1736 } else { 1737 for (int i = n-1; i >= 0; i--) { 1738 r[i] = u[i]; 1739 DEBUG(dbgs() << " " << r[i]); 1740 } 1741 } 1742 DEBUG(dbgs() << '\n'); 1743 } 1744#if 0 1745 DEBUG(dbgs() << '\n'); 1746#endif 1747} 1748 1749void APInt::divide(const APInt LHS, unsigned lhsWords, 1750 const APInt &RHS, unsigned rhsWords, 1751 APInt *Quotient, APInt *Remainder) 1752{ 1753 assert(lhsWords >= rhsWords && "Fractional result"); 1754 1755 // First, compose the values into an array of 32-bit words instead of 1756 // 64-bit words. This is a necessity of both the "short division" algorithm 1757 // and the Knuth "classical algorithm" which requires there to be native 1758 // operations for +, -, and * on an m bit value with an m*2 bit result. We 1759 // can't use 64-bit operands here because we don't have native results of 1760 // 128-bits. Furthermore, casting the 64-bit values to 32-bit values won't 1761 // work on large-endian machines. 1762 uint64_t mask = ~0ull >> (sizeof(unsigned)*CHAR_BIT); 1763 unsigned n = rhsWords * 2; 1764 unsigned m = (lhsWords * 2) - n; 1765 1766 // Allocate space for the temporary values we need either on the stack, if 1767 // it will fit, or on the heap if it won't. 1768 unsigned SPACE[128]; 1769 unsigned *U = 0; 1770 unsigned *V = 0; 1771 unsigned *Q = 0; 1772 unsigned *R = 0; 1773 if ((Remainder?4:3)*n+2*m+1 <= 128) { 1774 U = &SPACE[0]; 1775 V = &SPACE[m+n+1]; 1776 Q = &SPACE[(m+n+1) + n]; 1777 if (Remainder) 1778 R = &SPACE[(m+n+1) + n + (m+n)]; 1779 } else { 1780 U = new unsigned[m + n + 1]; 1781 V = new unsigned[n]; 1782 Q = new unsigned[m+n]; 1783 if (Remainder) 1784 R = new unsigned[n]; 1785 } 1786 1787 // Initialize the dividend 1788 memset(U, 0, (m+n+1)*sizeof(unsigned)); 1789 for (unsigned i = 0; i < lhsWords; ++i) { 1790 uint64_t tmp = (LHS.getNumWords() == 1 ? LHS.VAL : LHS.pVal[i]); 1791 U[i * 2] = (unsigned)(tmp & mask); 1792 U[i * 2 + 1] = (unsigned)(tmp >> (sizeof(unsigned)*CHAR_BIT)); 1793 } 1794 U[m+n] = 0; // this extra word is for "spill" in the Knuth algorithm. 1795 1796 // Initialize the divisor 1797 memset(V, 0, (n)*sizeof(unsigned)); 1798 for (unsigned i = 0; i < rhsWords; ++i) { 1799 uint64_t tmp = (RHS.getNumWords() == 1 ? RHS.VAL : RHS.pVal[i]); 1800 V[i * 2] = (unsigned)(tmp & mask); 1801 V[i * 2 + 1] = (unsigned)(tmp >> (sizeof(unsigned)*CHAR_BIT)); 1802 } 1803 1804 // initialize the quotient and remainder 1805 memset(Q, 0, (m+n) * sizeof(unsigned)); 1806 if (Remainder) 1807 memset(R, 0, n * sizeof(unsigned)); 1808 1809 // Now, adjust m and n for the Knuth division. n is the number of words in 1810 // the divisor. m is the number of words by which the dividend exceeds the 1811 // divisor (i.e. m+n is the length of the dividend). These sizes must not 1812 // contain any zero words or the Knuth algorithm fails. 1813 for (unsigned i = n; i > 0 && V[i-1] == 0; i--) { 1814 n--; 1815 m++; 1816 } 1817 for (unsigned i = m+n; i > 0 && U[i-1] == 0; i--) 1818 m--; 1819 1820 // If we're left with only a single word for the divisor, Knuth doesn't work 1821 // so we implement the short division algorithm here. This is much simpler 1822 // and faster because we are certain that we can divide a 64-bit quantity 1823 // by a 32-bit quantity at hardware speed and short division is simply a 1824 // series of such operations. This is just like doing short division but we 1825 // are using base 2^32 instead of base 10. 1826 assert(n != 0 && "Divide by zero?"); 1827 if (n == 1) { 1828 unsigned divisor = V[0]; 1829 unsigned remainder = 0; 1830 for (int i = m+n-1; i >= 0; i--) { 1831 uint64_t partial_dividend = uint64_t(remainder) << 32 | U[i]; 1832 if (partial_dividend == 0) { 1833 Q[i] = 0; 1834 remainder = 0; 1835 } else if (partial_dividend < divisor) { 1836 Q[i] = 0; 1837 remainder = (unsigned)partial_dividend; 1838 } else if (partial_dividend == divisor) { 1839 Q[i] = 1; 1840 remainder = 0; 1841 } else { 1842 Q[i] = (unsigned)(partial_dividend / divisor); 1843 remainder = (unsigned)(partial_dividend - (Q[i] * divisor)); 1844 } 1845 } 1846 if (R) 1847 R[0] = remainder; 1848 } else { 1849 // Now we're ready to invoke the Knuth classical divide algorithm. In this 1850 // case n > 1. 1851 KnuthDiv(U, V, Q, R, m, n); 1852 } 1853 1854 // If the caller wants the quotient 1855 if (Quotient) { 1856 // Set up the Quotient value's memory. 1857 if (Quotient->BitWidth != LHS.BitWidth) { 1858 if (Quotient->isSingleWord()) 1859 Quotient->VAL = 0; 1860 else 1861 delete [] Quotient->pVal; 1862 Quotient->BitWidth = LHS.BitWidth; 1863 if (!Quotient->isSingleWord()) 1864 Quotient->pVal = getClearedMemory(Quotient->getNumWords()); 1865 } else 1866 Quotient->clearAllBits(); 1867 1868 // The quotient is in Q. Reconstitute the quotient into Quotient's low 1869 // order words. 1870 if (lhsWords == 1) { 1871 uint64_t tmp = 1872 uint64_t(Q[0]) | (uint64_t(Q[1]) << (APINT_BITS_PER_WORD / 2)); 1873 if (Quotient->isSingleWord()) 1874 Quotient->VAL = tmp; 1875 else 1876 Quotient->pVal[0] = tmp; 1877 } else { 1878 assert(!Quotient->isSingleWord() && "Quotient APInt not large enough"); 1879 for (unsigned i = 0; i < lhsWords; ++i) 1880 Quotient->pVal[i] = 1881 uint64_t(Q[i*2]) | (uint64_t(Q[i*2+1]) << (APINT_BITS_PER_WORD / 2)); 1882 } 1883 } 1884 1885 // If the caller wants the remainder 1886 if (Remainder) { 1887 // Set up the Remainder value's memory. 1888 if (Remainder->BitWidth != RHS.BitWidth) { 1889 if (Remainder->isSingleWord()) 1890 Remainder->VAL = 0; 1891 else 1892 delete [] Remainder->pVal; 1893 Remainder->BitWidth = RHS.BitWidth; 1894 if (!Remainder->isSingleWord()) 1895 Remainder->pVal = getClearedMemory(Remainder->getNumWords()); 1896 } else 1897 Remainder->clearAllBits(); 1898 1899 // The remainder is in R. Reconstitute the remainder into Remainder's low 1900 // order words. 1901 if (rhsWords == 1) { 1902 uint64_t tmp = 1903 uint64_t(R[0]) | (uint64_t(R[1]) << (APINT_BITS_PER_WORD / 2)); 1904 if (Remainder->isSingleWord()) 1905 Remainder->VAL = tmp; 1906 else 1907 Remainder->pVal[0] = tmp; 1908 } else { 1909 assert(!Remainder->isSingleWord() && "Remainder APInt not large enough"); 1910 for (unsigned i = 0; i < rhsWords; ++i) 1911 Remainder->pVal[i] = 1912 uint64_t(R[i*2]) | (uint64_t(R[i*2+1]) << (APINT_BITS_PER_WORD / 2)); 1913 } 1914 } 1915 1916 // Clean up the memory we allocated. 1917 if (U != &SPACE[0]) { 1918 delete [] U; 1919 delete [] V; 1920 delete [] Q; 1921 delete [] R; 1922 } 1923} 1924 1925APInt APInt::udiv(const APInt& RHS) const { 1926 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 1927 1928 // First, deal with the easy case 1929 if (isSingleWord()) { 1930 assert(RHS.VAL != 0 && "Divide by zero?"); 1931 return APInt(BitWidth, VAL / RHS.VAL); 1932 } 1933 1934 // Get some facts about the LHS and RHS number of bits and words 1935 unsigned rhsBits = RHS.getActiveBits(); 1936 unsigned rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1); 1937 assert(rhsWords && "Divided by zero???"); 1938 unsigned lhsBits = this->getActiveBits(); 1939 unsigned lhsWords = !lhsBits ? 0 : (APInt::whichWord(lhsBits - 1) + 1); 1940 1941 // Deal with some degenerate cases 1942 if (!lhsWords) 1943 // 0 / X ===> 0 1944 return APInt(BitWidth, 0); 1945 else if (lhsWords < rhsWords || this->ult(RHS)) { 1946 // X / Y ===> 0, iff X < Y 1947 return APInt(BitWidth, 0); 1948 } else if (*this == RHS) { 1949 // X / X ===> 1 1950 return APInt(BitWidth, 1); 1951 } else if (lhsWords == 1 && rhsWords == 1) { 1952 // All high words are zero, just use native divide 1953 return APInt(BitWidth, this->pVal[0] / RHS.pVal[0]); 1954 } 1955 1956 // We have to compute it the hard way. Invoke the Knuth divide algorithm. 1957 APInt Quotient(1,0); // to hold result. 1958 divide(*this, lhsWords, RHS, rhsWords, &Quotient, 0); 1959 return Quotient; 1960} 1961 1962APInt APInt::urem(const APInt& RHS) const { 1963 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same"); 1964 if (isSingleWord()) { 1965 assert(RHS.VAL != 0 && "Remainder by zero?"); 1966 return APInt(BitWidth, VAL % RHS.VAL); 1967 } 1968 1969 // Get some facts about the LHS 1970 unsigned lhsBits = getActiveBits(); 1971 unsigned lhsWords = !lhsBits ? 0 : (whichWord(lhsBits - 1) + 1); 1972 1973 // Get some facts about the RHS 1974 unsigned rhsBits = RHS.getActiveBits(); 1975 unsigned rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1); 1976 assert(rhsWords && "Performing remainder operation by zero ???"); 1977 1978 // Check the degenerate cases 1979 if (lhsWords == 0) { 1980 // 0 % Y ===> 0 1981 return APInt(BitWidth, 0); 1982 } else if (lhsWords < rhsWords || this->ult(RHS)) { 1983 // X % Y ===> X, iff X < Y 1984 return *this; 1985 } else if (*this == RHS) { 1986 // X % X == 0; 1987 return APInt(BitWidth, 0); 1988 } else if (lhsWords == 1) { 1989 // All high words are zero, just use native remainder 1990 return APInt(BitWidth, pVal[0] % RHS.pVal[0]); 1991 } 1992 1993 // We have to compute it the hard way. Invoke the Knuth divide algorithm. 1994 APInt Remainder(1,0); 1995 divide(*this, lhsWords, RHS, rhsWords, 0, &Remainder); 1996 return Remainder; 1997} 1998 1999void APInt::udivrem(const APInt &LHS, const APInt &RHS, 2000 APInt &Quotient, APInt &Remainder) { 2001 // Get some size facts about the dividend and divisor 2002 unsigned lhsBits = LHS.getActiveBits(); 2003 unsigned lhsWords = !lhsBits ? 0 : (APInt::whichWord(lhsBits - 1) + 1); 2004 unsigned rhsBits = RHS.getActiveBits(); 2005 unsigned rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1); 2006 2007 // Check the degenerate cases 2008 if (lhsWords == 0) { 2009 Quotient = 0; // 0 / Y ===> 0 2010 Remainder = 0; // 0 % Y ===> 0 2011 return; 2012 } 2013 2014 if (lhsWords < rhsWords || LHS.ult(RHS)) { 2015 Remainder = LHS; // X % Y ===> X, iff X < Y 2016 Quotient = 0; // X / Y ===> 0, iff X < Y 2017 return; 2018 } 2019 2020 if (LHS == RHS) { 2021 Quotient = 1; // X / X ===> 1 2022 Remainder = 0; // X % X ===> 0; 2023 return; 2024 } 2025 2026 if (lhsWords == 1 && rhsWords == 1) { 2027 // There is only one word to consider so use the native versions. 2028 uint64_t lhsValue = LHS.isSingleWord() ? LHS.VAL : LHS.pVal[0]; 2029 uint64_t rhsValue = RHS.isSingleWord() ? RHS.VAL : RHS.pVal[0]; 2030 Quotient = APInt(LHS.getBitWidth(), lhsValue / rhsValue); 2031 Remainder = APInt(LHS.getBitWidth(), lhsValue % rhsValue); 2032 return; 2033 } 2034 2035 // Okay, lets do it the long way 2036 divide(LHS, lhsWords, RHS, rhsWords, &Quotient, &Remainder); 2037} 2038 2039APInt APInt::sadd_ov(const APInt &RHS, bool &Overflow) const { 2040 APInt Res = *this+RHS; 2041 Overflow = isNonNegative() == RHS.isNonNegative() && 2042 Res.isNonNegative() != isNonNegative(); 2043 return Res; 2044} 2045 2046APInt APInt::uadd_ov(const APInt &RHS, bool &Overflow) const { 2047 APInt Res = *this+RHS; 2048 Overflow = Res.ult(RHS); 2049 return Res; 2050} 2051 2052APInt APInt::ssub_ov(const APInt &RHS, bool &Overflow) const { 2053 APInt Res = *this - RHS; 2054 Overflow = isNonNegative() != RHS.isNonNegative() && 2055 Res.isNonNegative() != isNonNegative(); 2056 return Res; 2057} 2058 2059APInt APInt::usub_ov(const APInt &RHS, bool &Overflow) const { 2060 APInt Res = *this-RHS; 2061 Overflow = Res.ugt(*this); 2062 return Res; 2063} 2064 2065APInt APInt::sdiv_ov(const APInt &RHS, bool &Overflow) const { 2066 // MININT/-1 --> overflow. 2067 Overflow = isMinSignedValue() && RHS.isAllOnesValue(); 2068 return sdiv(RHS); 2069} 2070 2071APInt APInt::smul_ov(const APInt &RHS, bool &Overflow) const { 2072 APInt Res = *this * RHS; 2073 2074 if (*this != 0 && RHS != 0) 2075 Overflow = Res.sdiv(RHS) != *this || Res.sdiv(*this) != RHS; 2076 else 2077 Overflow = false; 2078 return Res; 2079} 2080 2081APInt APInt::umul_ov(const APInt &RHS, bool &Overflow) const { 2082 APInt Res = *this * RHS; 2083 2084 if (*this != 0 && RHS != 0) 2085 Overflow = Res.udiv(RHS) != *this || Res.udiv(*this) != RHS; 2086 else 2087 Overflow = false; 2088 return Res; 2089} 2090 2091APInt APInt::sshl_ov(unsigned ShAmt, bool &Overflow) const { 2092 Overflow = ShAmt >= getBitWidth(); 2093 if (Overflow) 2094 ShAmt = getBitWidth()-1; 2095 2096 if (isNonNegative()) // Don't allow sign change. 2097 Overflow = ShAmt >= countLeadingZeros(); 2098 else 2099 Overflow = ShAmt >= countLeadingOnes(); 2100 2101 return *this << ShAmt; 2102} 2103 2104 2105 2106 2107void APInt::fromString(unsigned numbits, StringRef str, uint8_t radix) { 2108 // Check our assumptions here 2109 assert(!str.empty() && "Invalid string length"); 2110 assert((radix == 10 || radix == 8 || radix == 16 || radix == 2) && 2111 "Radix should be 2, 8, 10, or 16!"); 2112 2113 StringRef::iterator p = str.begin(); 2114 size_t slen = str.size(); 2115 bool isNeg = *p == '-'; 2116 if (*p == '-' || *p == '+') { 2117 p++; 2118 slen--; 2119 assert(slen && "String is only a sign, needs a value."); 2120 } 2121 assert((slen <= numbits || radix != 2) && "Insufficient bit width"); 2122 assert(((slen-1)*3 <= numbits || radix != 8) && "Insufficient bit width"); 2123 assert(((slen-1)*4 <= numbits || radix != 16) && "Insufficient bit width"); 2124 assert((((slen-1)*64)/22 <= numbits || radix != 10) && 2125 "Insufficient bit width"); 2126 2127 // Allocate memory 2128 if (!isSingleWord()) 2129 pVal = getClearedMemory(getNumWords()); 2130 2131 // Figure out if we can shift instead of multiply 2132 unsigned shift = (radix == 16 ? 4 : radix == 8 ? 3 : radix == 2 ? 1 : 0); 2133 2134 // Set up an APInt for the digit to add outside the loop so we don't 2135 // constantly construct/destruct it. 2136 APInt apdigit(getBitWidth(), 0); 2137 APInt apradix(getBitWidth(), radix); 2138 2139 // Enter digit traversal loop 2140 for (StringRef::iterator e = str.end(); p != e; ++p) { 2141 unsigned digit = getDigit(*p, radix); 2142 assert(digit < radix && "Invalid character in digit string"); 2143 2144 // Shift or multiply the value by the radix 2145 if (slen > 1) { 2146 if (shift) 2147 *this <<= shift; 2148 else 2149 *this *= apradix; 2150 } 2151 2152 // Add in the digit we just interpreted 2153 if (apdigit.isSingleWord()) 2154 apdigit.VAL = digit; 2155 else 2156 apdigit.pVal[0] = digit; 2157 *this += apdigit; 2158 } 2159 // If its negative, put it in two's complement form 2160 if (isNeg) { 2161 (*this)--; 2162 this->flipAllBits(); 2163 } 2164} 2165 2166void APInt::toString(SmallVectorImpl<char> &Str, unsigned Radix, 2167 bool Signed) const { 2168 assert((Radix == 10 || Radix == 8 || Radix == 16 || Radix == 2) && 2169 "Radix should be 2, 8, 10, or 16!"); 2170 2171 // First, check for a zero value and just short circuit the logic below. 2172 if (*this == 0) { 2173 Str.push_back('0'); 2174 return; 2175 } 2176 2177 static const char Digits[] = "0123456789ABCDEF"; 2178 2179 if (isSingleWord()) { 2180 char Buffer[65]; 2181 char *BufPtr = Buffer+65; 2182 2183 uint64_t N; 2184 if (!Signed) { 2185 N = getZExtValue(); 2186 } else { 2187 int64_t I = getSExtValue(); 2188 if (I >= 0) { 2189 N = I; 2190 } else { 2191 Str.push_back('-'); 2192 N = -(uint64_t)I; 2193 } 2194 } 2195 2196 while (N) { 2197 *--BufPtr = Digits[N % Radix]; 2198 N /= Radix; 2199 } 2200 Str.append(BufPtr, Buffer+65); 2201 return; 2202 } 2203 2204 APInt Tmp(*this); 2205 2206 if (Signed && isNegative()) { 2207 // They want to print the signed version and it is a negative value 2208 // Flip the bits and add one to turn it into the equivalent positive 2209 // value and put a '-' in the result. 2210 Tmp.flipAllBits(); 2211 Tmp++; 2212 Str.push_back('-'); 2213 } 2214 2215 // We insert the digits backward, then reverse them to get the right order. 2216 unsigned StartDig = Str.size(); 2217 2218 // For the 2, 8 and 16 bit cases, we can just shift instead of divide 2219 // because the number of bits per digit (1, 3 and 4 respectively) divides 2220 // equaly. We just shift until the value is zero. 2221 if (Radix != 10) { 2222 // Just shift tmp right for each digit width until it becomes zero 2223 unsigned ShiftAmt = (Radix == 16 ? 4 : (Radix == 8 ? 3 : 1)); 2224 unsigned MaskAmt = Radix - 1; 2225 2226 while (Tmp != 0) { 2227 unsigned Digit = unsigned(Tmp.getRawData()[0]) & MaskAmt; 2228 Str.push_back(Digits[Digit]); 2229 Tmp = Tmp.lshr(ShiftAmt); 2230 } 2231 } else { 2232 APInt divisor(4, 10); 2233 while (Tmp != 0) { 2234 APInt APdigit(1, 0); 2235 APInt tmp2(Tmp.getBitWidth(), 0); 2236 divide(Tmp, Tmp.getNumWords(), divisor, divisor.getNumWords(), &tmp2, 2237 &APdigit); 2238 unsigned Digit = (unsigned)APdigit.getZExtValue(); 2239 assert(Digit < Radix && "divide failed"); 2240 Str.push_back(Digits[Digit]); 2241 Tmp = tmp2; 2242 } 2243 } 2244 2245 // Reverse the digits before returning. 2246 std::reverse(Str.begin()+StartDig, Str.end()); 2247} 2248 2249/// toString - This returns the APInt as a std::string. Note that this is an 2250/// inefficient method. It is better to pass in a SmallVector/SmallString 2251/// to the methods above. 2252std::string APInt::toString(unsigned Radix = 10, bool Signed = true) const { 2253 SmallString<40> S; 2254 toString(S, Radix, Signed); 2255 return S.str(); 2256} 2257 2258 2259void APInt::dump() const { 2260 SmallString<40> S, U; 2261 this->toStringUnsigned(U); 2262 this->toStringSigned(S); 2263 dbgs() << "APInt(" << BitWidth << "b, " 2264 << U.str() << "u " << S.str() << "s)"; 2265} 2266 2267void APInt::print(raw_ostream &OS, bool isSigned) const { 2268 SmallString<40> S; 2269 this->toString(S, 10, isSigned); 2270 OS << S.str(); 2271} 2272 2273// This implements a variety of operations on a representation of 2274// arbitrary precision, two's-complement, bignum integer values. 2275 2276// Assumed by lowHalf, highHalf, partMSB and partLSB. A fairly safe 2277// and unrestricting assumption. 2278#define COMPILE_TIME_ASSERT(cond) extern int CTAssert[(cond) ? 1 : -1] 2279COMPILE_TIME_ASSERT(integerPartWidth % 2 == 0); 2280 2281/* Some handy functions local to this file. */ 2282namespace { 2283 2284 /* Returns the integer part with the least significant BITS set. 2285 BITS cannot be zero. */ 2286 static inline integerPart 2287 lowBitMask(unsigned int bits) 2288 { 2289 assert(bits != 0 && bits <= integerPartWidth); 2290 2291 return ~(integerPart) 0 >> (integerPartWidth - bits); 2292 } 2293 2294 /* Returns the value of the lower half of PART. */ 2295 static inline integerPart 2296 lowHalf(integerPart part) 2297 { 2298 return part & lowBitMask(integerPartWidth / 2); 2299 } 2300 2301 /* Returns the value of the upper half of PART. */ 2302 static inline integerPart 2303 highHalf(integerPart part) 2304 { 2305 return part >> (integerPartWidth / 2); 2306 } 2307 2308 /* Returns the bit number of the most significant set bit of a part. 2309 If the input number has no bits set -1U is returned. */ 2310 static unsigned int 2311 partMSB(integerPart value) 2312 { 2313 unsigned int n, msb; 2314 2315 if (value == 0) 2316 return -1U; 2317 2318 n = integerPartWidth / 2; 2319 2320 msb = 0; 2321 do { 2322 if (value >> n) { 2323 value >>= n; 2324 msb += n; 2325 } 2326 2327 n >>= 1; 2328 } while (n); 2329 2330 return msb; 2331 } 2332 2333 /* Returns the bit number of the least significant set bit of a 2334 part. If the input number has no bits set -1U is returned. */ 2335 static unsigned int 2336 partLSB(integerPart value) 2337 { 2338 unsigned int n, lsb; 2339 2340 if (value == 0) 2341 return -1U; 2342 2343 lsb = integerPartWidth - 1; 2344 n = integerPartWidth / 2; 2345 2346 do { 2347 if (value << n) { 2348 value <<= n; 2349 lsb -= n; 2350 } 2351 2352 n >>= 1; 2353 } while (n); 2354 2355 return lsb; 2356 } 2357} 2358 2359/* Sets the least significant part of a bignum to the input value, and 2360 zeroes out higher parts. */ 2361void 2362APInt::tcSet(integerPart *dst, integerPart part, unsigned int parts) 2363{ 2364 unsigned int i; 2365 2366 assert(parts > 0); 2367 2368 dst[0] = part; 2369 for (i = 1; i < parts; i++) 2370 dst[i] = 0; 2371} 2372 2373/* Assign one bignum to another. */ 2374void 2375APInt::tcAssign(integerPart *dst, const integerPart *src, unsigned int parts) 2376{ 2377 unsigned int i; 2378 2379 for (i = 0; i < parts; i++) 2380 dst[i] = src[i]; 2381} 2382 2383/* Returns true if a bignum is zero, false otherwise. */ 2384bool 2385APInt::tcIsZero(const integerPart *src, unsigned int parts) 2386{ 2387 unsigned int i; 2388 2389 for (i = 0; i < parts; i++) 2390 if (src[i]) 2391 return false; 2392 2393 return true; 2394} 2395 2396/* Extract the given bit of a bignum; returns 0 or 1. */ 2397int 2398APInt::tcExtractBit(const integerPart *parts, unsigned int bit) 2399{ 2400 return (parts[bit / integerPartWidth] & 2401 ((integerPart) 1 << bit % integerPartWidth)) != 0; 2402} 2403 2404/* Set the given bit of a bignum. */ 2405void 2406APInt::tcSetBit(integerPart *parts, unsigned int bit) 2407{ 2408 parts[bit / integerPartWidth] |= (integerPart) 1 << (bit % integerPartWidth); 2409} 2410 2411/* Clears the given bit of a bignum. */ 2412void 2413APInt::tcClearBit(integerPart *parts, unsigned int bit) 2414{ 2415 parts[bit / integerPartWidth] &= 2416 ~((integerPart) 1 << (bit % integerPartWidth)); 2417} 2418 2419/* Returns the bit number of the least significant set bit of a 2420 number. If the input number has no bits set -1U is returned. */ 2421unsigned int 2422APInt::tcLSB(const integerPart *parts, unsigned int n) 2423{ 2424 unsigned int i, lsb; 2425 2426 for (i = 0; i < n; i++) { 2427 if (parts[i] != 0) { 2428 lsb = partLSB(parts[i]); 2429 2430 return lsb + i * integerPartWidth; 2431 } 2432 } 2433 2434 return -1U; 2435} 2436 2437/* Returns the bit number of the most significant set bit of a number. 2438 If the input number has no bits set -1U is returned. */ 2439unsigned int 2440APInt::tcMSB(const integerPart *parts, unsigned int n) 2441{ 2442 unsigned int msb; 2443 2444 do { 2445 --n; 2446 2447 if (parts[n] != 0) { 2448 msb = partMSB(parts[n]); 2449 2450 return msb + n * integerPartWidth; 2451 } 2452 } while (n); 2453 2454 return -1U; 2455} 2456 2457/* Copy the bit vector of width srcBITS from SRC, starting at bit 2458 srcLSB, to DST, of dstCOUNT parts, such that the bit srcLSB becomes 2459 the least significant bit of DST. All high bits above srcBITS in 2460 DST are zero-filled. */ 2461void 2462APInt::tcExtract(integerPart *dst, unsigned int dstCount,const integerPart *src, 2463 unsigned int srcBits, unsigned int srcLSB) 2464{ 2465 unsigned int firstSrcPart, dstParts, shift, n; 2466 2467 dstParts = (srcBits + integerPartWidth - 1) / integerPartWidth; 2468 assert(dstParts <= dstCount); 2469 2470 firstSrcPart = srcLSB / integerPartWidth; 2471 tcAssign (dst, src + firstSrcPart, dstParts); 2472 2473 shift = srcLSB % integerPartWidth; 2474 tcShiftRight (dst, dstParts, shift); 2475 2476 /* We now have (dstParts * integerPartWidth - shift) bits from SRC 2477 in DST. If this is less that srcBits, append the rest, else 2478 clear the high bits. */ 2479 n = dstParts * integerPartWidth - shift; 2480 if (n < srcBits) { 2481 integerPart mask = lowBitMask (srcBits - n); 2482 dst[dstParts - 1] |= ((src[firstSrcPart + dstParts] & mask) 2483 << n % integerPartWidth); 2484 } else if (n > srcBits) { 2485 if (srcBits % integerPartWidth) 2486 dst[dstParts - 1] &= lowBitMask (srcBits % integerPartWidth); 2487 } 2488 2489 /* Clear high parts. */ 2490 while (dstParts < dstCount) 2491 dst[dstParts++] = 0; 2492} 2493 2494/* DST += RHS + C where C is zero or one. Returns the carry flag. */ 2495integerPart 2496APInt::tcAdd(integerPart *dst, const integerPart *rhs, 2497 integerPart c, unsigned int parts) 2498{ 2499 unsigned int i; 2500 2501 assert(c <= 1); 2502 2503 for (i = 0; i < parts; i++) { 2504 integerPart l; 2505 2506 l = dst[i]; 2507 if (c) { 2508 dst[i] += rhs[i] + 1; 2509 c = (dst[i] <= l); 2510 } else { 2511 dst[i] += rhs[i]; 2512 c = (dst[i] < l); 2513 } 2514 } 2515 2516 return c; 2517} 2518 2519/* DST -= RHS + C where C is zero or one. Returns the carry flag. */ 2520integerPart 2521APInt::tcSubtract(integerPart *dst, const integerPart *rhs, 2522 integerPart c, unsigned int parts) 2523{ 2524 unsigned int i; 2525 2526 assert(c <= 1); 2527 2528 for (i = 0; i < parts; i++) { 2529 integerPart l; 2530 2531 l = dst[i]; 2532 if (c) { 2533 dst[i] -= rhs[i] + 1; 2534 c = (dst[i] >= l); 2535 } else { 2536 dst[i] -= rhs[i]; 2537 c = (dst[i] > l); 2538 } 2539 } 2540 2541 return c; 2542} 2543 2544/* Negate a bignum in-place. */ 2545void 2546APInt::tcNegate(integerPart *dst, unsigned int parts) 2547{ 2548 tcComplement(dst, parts); 2549 tcIncrement(dst, parts); 2550} 2551 2552/* DST += SRC * MULTIPLIER + CARRY if add is true 2553 DST = SRC * MULTIPLIER + CARRY if add is false 2554 2555 Requires 0 <= DSTPARTS <= SRCPARTS + 1. If DST overlaps SRC 2556 they must start at the same point, i.e. DST == SRC. 2557 2558 If DSTPARTS == SRCPARTS + 1 no overflow occurs and zero is 2559 returned. Otherwise DST is filled with the least significant 2560 DSTPARTS parts of the result, and if all of the omitted higher 2561 parts were zero return zero, otherwise overflow occurred and 2562 return one. */ 2563int 2564APInt::tcMultiplyPart(integerPart *dst, const integerPart *src, 2565 integerPart multiplier, integerPart carry, 2566 unsigned int srcParts, unsigned int dstParts, 2567 bool add) 2568{ 2569 unsigned int i, n; 2570 2571 /* Otherwise our writes of DST kill our later reads of SRC. */ 2572 assert(dst <= src || dst >= src + srcParts); 2573 assert(dstParts <= srcParts + 1); 2574 2575 /* N loops; minimum of dstParts and srcParts. */ 2576 n = dstParts < srcParts ? dstParts: srcParts; 2577 2578 for (i = 0; i < n; i++) { 2579 integerPart low, mid, high, srcPart; 2580 2581 /* [ LOW, HIGH ] = MULTIPLIER * SRC[i] + DST[i] + CARRY. 2582 2583 This cannot overflow, because 2584 2585 (n - 1) * (n - 1) + 2 (n - 1) = (n - 1) * (n + 1) 2586 2587 which is less than n^2. */ 2588 2589 srcPart = src[i]; 2590 2591 if (multiplier == 0 || srcPart == 0) { 2592 low = carry; 2593 high = 0; 2594 } else { 2595 low = lowHalf(srcPart) * lowHalf(multiplier); 2596 high = highHalf(srcPart) * highHalf(multiplier); 2597 2598 mid = lowHalf(srcPart) * highHalf(multiplier); 2599 high += highHalf(mid); 2600 mid <<= integerPartWidth / 2; 2601 if (low + mid < low) 2602 high++; 2603 low += mid; 2604 2605 mid = highHalf(srcPart) * lowHalf(multiplier); 2606 high += highHalf(mid); 2607 mid <<= integerPartWidth / 2; 2608 if (low + mid < low) 2609 high++; 2610 low += mid; 2611 2612 /* Now add carry. */ 2613 if (low + carry < low) 2614 high++; 2615 low += carry; 2616 } 2617 2618 if (add) { 2619 /* And now DST[i], and store the new low part there. */ 2620 if (low + dst[i] < low) 2621 high++; 2622 dst[i] += low; 2623 } else 2624 dst[i] = low; 2625 2626 carry = high; 2627 } 2628 2629 if (i < dstParts) { 2630 /* Full multiplication, there is no overflow. */ 2631 assert(i + 1 == dstParts); 2632 dst[i] = carry; 2633 return 0; 2634 } else { 2635 /* We overflowed if there is carry. */ 2636 if (carry) 2637 return 1; 2638 2639 /* We would overflow if any significant unwritten parts would be 2640 non-zero. This is true if any remaining src parts are non-zero 2641 and the multiplier is non-zero. */ 2642 if (multiplier) 2643 for (; i < srcParts; i++) 2644 if (src[i]) 2645 return 1; 2646 2647 /* We fitted in the narrow destination. */ 2648 return 0; 2649 } 2650} 2651 2652/* DST = LHS * RHS, where DST has the same width as the operands and 2653 is filled with the least significant parts of the result. Returns 2654 one if overflow occurred, otherwise zero. DST must be disjoint 2655 from both operands. */ 2656int 2657APInt::tcMultiply(integerPart *dst, const integerPart *lhs, 2658 const integerPart *rhs, unsigned int parts) 2659{ 2660 unsigned int i; 2661 int overflow; 2662 2663 assert(dst != lhs && dst != rhs); 2664 2665 overflow = 0; 2666 tcSet(dst, 0, parts); 2667 2668 for (i = 0; i < parts; i++) 2669 overflow |= tcMultiplyPart(&dst[i], lhs, rhs[i], 0, parts, 2670 parts - i, true); 2671 2672 return overflow; 2673} 2674 2675/* DST = LHS * RHS, where DST has width the sum of the widths of the 2676 operands. No overflow occurs. DST must be disjoint from both 2677 operands. Returns the number of parts required to hold the 2678 result. */ 2679unsigned int 2680APInt::tcFullMultiply(integerPart *dst, const integerPart *lhs, 2681 const integerPart *rhs, unsigned int lhsParts, 2682 unsigned int rhsParts) 2683{ 2684 /* Put the narrower number on the LHS for less loops below. */ 2685 if (lhsParts > rhsParts) { 2686 return tcFullMultiply (dst, rhs, lhs, rhsParts, lhsParts); 2687 } else { 2688 unsigned int n; 2689 2690 assert(dst != lhs && dst != rhs); 2691 2692 tcSet(dst, 0, rhsParts); 2693 2694 for (n = 0; n < lhsParts; n++) 2695 tcMultiplyPart(&dst[n], rhs, lhs[n], 0, rhsParts, rhsParts + 1, true); 2696 2697 n = lhsParts + rhsParts; 2698 2699 return n - (dst[n - 1] == 0); 2700 } 2701} 2702 2703/* If RHS is zero LHS and REMAINDER are left unchanged, return one. 2704 Otherwise set LHS to LHS / RHS with the fractional part discarded, 2705 set REMAINDER to the remainder, return zero. i.e. 2706 2707 OLD_LHS = RHS * LHS + REMAINDER 2708 2709 SCRATCH is a bignum of the same size as the operands and result for 2710 use by the routine; its contents need not be initialized and are 2711 destroyed. LHS, REMAINDER and SCRATCH must be distinct. 2712*/ 2713int 2714APInt::tcDivide(integerPart *lhs, const integerPart *rhs, 2715 integerPart *remainder, integerPart *srhs, 2716 unsigned int parts) 2717{ 2718 unsigned int n, shiftCount; 2719 integerPart mask; 2720 2721 assert(lhs != remainder && lhs != srhs && remainder != srhs); 2722 2723 shiftCount = tcMSB(rhs, parts) + 1; 2724 if (shiftCount == 0) 2725 return true; 2726 2727 shiftCount = parts * integerPartWidth - shiftCount; 2728 n = shiftCount / integerPartWidth; 2729 mask = (integerPart) 1 << (shiftCount % integerPartWidth); 2730 2731 tcAssign(srhs, rhs, parts); 2732 tcShiftLeft(srhs, parts, shiftCount); 2733 tcAssign(remainder, lhs, parts); 2734 tcSet(lhs, 0, parts); 2735 2736 /* Loop, subtracting SRHS if REMAINDER is greater and adding that to 2737 the total. */ 2738 for (;;) { 2739 int compare; 2740 2741 compare = tcCompare(remainder, srhs, parts); 2742 if (compare >= 0) { 2743 tcSubtract(remainder, srhs, 0, parts); 2744 lhs[n] |= mask; 2745 } 2746 2747 if (shiftCount == 0) 2748 break; 2749 shiftCount--; 2750 tcShiftRight(srhs, parts, 1); 2751 if ((mask >>= 1) == 0) 2752 mask = (integerPart) 1 << (integerPartWidth - 1), n--; 2753 } 2754 2755 return false; 2756} 2757 2758/* Shift a bignum left COUNT bits in-place. Shifted in bits are zero. 2759 There are no restrictions on COUNT. */ 2760void 2761APInt::tcShiftLeft(integerPart *dst, unsigned int parts, unsigned int count) 2762{ 2763 if (count) { 2764 unsigned int jump, shift; 2765 2766 /* Jump is the inter-part jump; shift is is intra-part shift. */ 2767 jump = count / integerPartWidth; 2768 shift = count % integerPartWidth; 2769 2770 while (parts > jump) { 2771 integerPart part; 2772 2773 parts--; 2774 2775 /* dst[i] comes from the two parts src[i - jump] and, if we have 2776 an intra-part shift, src[i - jump - 1]. */ 2777 part = dst[parts - jump]; 2778 if (shift) { 2779 part <<= shift; 2780 if (parts >= jump + 1) 2781 part |= dst[parts - jump - 1] >> (integerPartWidth - shift); 2782 } 2783 2784 dst[parts] = part; 2785 } 2786 2787 while (parts > 0) 2788 dst[--parts] = 0; 2789 } 2790} 2791 2792/* Shift a bignum right COUNT bits in-place. Shifted in bits are 2793 zero. There are no restrictions on COUNT. */ 2794void 2795APInt::tcShiftRight(integerPart *dst, unsigned int parts, unsigned int count) 2796{ 2797 if (count) { 2798 unsigned int i, jump, shift; 2799 2800 /* Jump is the inter-part jump; shift is is intra-part shift. */ 2801 jump = count / integerPartWidth; 2802 shift = count % integerPartWidth; 2803 2804 /* Perform the shift. This leaves the most significant COUNT bits 2805 of the result at zero. */ 2806 for (i = 0; i < parts; i++) { 2807 integerPart part; 2808 2809 if (i + jump >= parts) { 2810 part = 0; 2811 } else { 2812 part = dst[i + jump]; 2813 if (shift) { 2814 part >>= shift; 2815 if (i + jump + 1 < parts) 2816 part |= dst[i + jump + 1] << (integerPartWidth - shift); 2817 } 2818 } 2819 2820 dst[i] = part; 2821 } 2822 } 2823} 2824 2825/* Bitwise and of two bignums. */ 2826void 2827APInt::tcAnd(integerPart *dst, const integerPart *rhs, unsigned int parts) 2828{ 2829 unsigned int i; 2830 2831 for (i = 0; i < parts; i++) 2832 dst[i] &= rhs[i]; 2833} 2834 2835/* Bitwise inclusive or of two bignums. */ 2836void 2837APInt::tcOr(integerPart *dst, const integerPart *rhs, unsigned int parts) 2838{ 2839 unsigned int i; 2840 2841 for (i = 0; i < parts; i++) 2842 dst[i] |= rhs[i]; 2843} 2844 2845/* Bitwise exclusive or of two bignums. */ 2846void 2847APInt::tcXor(integerPart *dst, const integerPart *rhs, unsigned int parts) 2848{ 2849 unsigned int i; 2850 2851 for (i = 0; i < parts; i++) 2852 dst[i] ^= rhs[i]; 2853} 2854 2855/* Complement a bignum in-place. */ 2856void 2857APInt::tcComplement(integerPart *dst, unsigned int parts) 2858{ 2859 unsigned int i; 2860 2861 for (i = 0; i < parts; i++) 2862 dst[i] = ~dst[i]; 2863} 2864 2865/* Comparison (unsigned) of two bignums. */ 2866int 2867APInt::tcCompare(const integerPart *lhs, const integerPart *rhs, 2868 unsigned int parts) 2869{ 2870 while (parts) { 2871 parts--; 2872 if (lhs[parts] == rhs[parts]) 2873 continue; 2874 2875 if (lhs[parts] > rhs[parts]) 2876 return 1; 2877 else 2878 return -1; 2879 } 2880 2881 return 0; 2882} 2883 2884/* Increment a bignum in-place, return the carry flag. */ 2885integerPart 2886APInt::tcIncrement(integerPart *dst, unsigned int parts) 2887{ 2888 unsigned int i; 2889 2890 for (i = 0; i < parts; i++) 2891 if (++dst[i] != 0) 2892 break; 2893 2894 return i == parts; 2895} 2896 2897/* Set the least significant BITS bits of a bignum, clear the 2898 rest. */ 2899void 2900APInt::tcSetLeastSignificantBits(integerPart *dst, unsigned int parts, 2901 unsigned int bits) 2902{ 2903 unsigned int i; 2904 2905 i = 0; 2906 while (bits > integerPartWidth) { 2907 dst[i++] = ~(integerPart) 0; 2908 bits -= integerPartWidth; 2909 } 2910 2911 if (bits) 2912 dst[i++] = ~(integerPart) 0 >> (integerPartWidth - bits); 2913 2914 while (i < parts) 2915 dst[i++] = 0; 2916} 2917