1 //===-- APInt.cpp - Implement APInt class ---------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements a class to represent arbitrary precision integer
11 // constant values and provide a variety of arithmetic operations on them.
13 //===----------------------------------------------------------------------===//
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"
30 /// A utility function for allocating memory, checking for allocation failures,
31 /// and ensuring the contents are zeroed.
32 inline 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));
39 /// A utility function for allocating memory and checking for allocation
40 /// failure. The content is not zeroed.
41 inline static uint64_t* getMemory(unsigned numWords) {
42 uint64_t * result = new uint64_t[numWords];
43 assert(result && "APInt memory allocation fails!");
47 /// A utility function that converts a character to a digit.
48 inline static unsigned getDigit(char cdigit, uint8_t radix) {
51 if (radix == 16 || radix == 36) {
75 void APInt::initSlowCase(unsigned numBits, uint64_t val, bool isSigned) {
76 pVal = getClearedMemory(getNumWords());
78 if (isSigned && int64_t(val) < 0)
79 for (unsigned i = 1; i < getNumWords(); ++i)
83 void APInt::initSlowCase(const APInt& that) {
84 pVal = getMemory(getNumWords());
85 memcpy(pVal, that.pVal, getNumWords() * APINT_WORD_SIZE);
88 void APInt::initFromArray(ArrayRef<uint64_t> bigVal) {
89 assert(BitWidth && "Bitwidth too small");
90 assert(bigVal.data() && "Null pointer detected!");
94 // Get memory, cleared to 0
95 pVal = getClearedMemory(getNumWords());
96 // Calculate the number of words to copy
97 unsigned words = std::min<unsigned>(bigVal.size(), getNumWords());
98 // Copy the words from bigVal to pVal
99 memcpy(pVal, bigVal.data(), words * APINT_WORD_SIZE);
101 // Make sure unused high bits are cleared
105 APInt::APInt(unsigned numBits, ArrayRef<uint64_t> bigVal)
106 : BitWidth(numBits), VAL(0) {
107 initFromArray(bigVal);
110 APInt::APInt(unsigned numBits, unsigned numWords, const uint64_t bigVal[])
111 : BitWidth(numBits), VAL(0) {
112 initFromArray(makeArrayRef(bigVal, numWords));
115 APInt::APInt(unsigned numbits, StringRef Str, uint8_t radix)
116 : BitWidth(numbits), VAL(0) {
117 assert(BitWidth && "Bitwidth too small");
118 fromString(numbits, Str, radix);
121 APInt& APInt::AssignSlowCase(const APInt& RHS) {
122 // Don't do anything for X = X
126 if (BitWidth == RHS.getBitWidth()) {
127 // assume same bit-width single-word case is already handled
128 assert(!isSingleWord());
129 memcpy(pVal, RHS.pVal, getNumWords() * APINT_WORD_SIZE);
133 if (isSingleWord()) {
134 // assume case where both are single words is already handled
135 assert(!RHS.isSingleWord());
137 pVal = getMemory(RHS.getNumWords());
138 memcpy(pVal, RHS.pVal, RHS.getNumWords() * APINT_WORD_SIZE);
139 } else if (getNumWords() == RHS.getNumWords())
140 memcpy(pVal, RHS.pVal, RHS.getNumWords() * APINT_WORD_SIZE);
141 else if (RHS.isSingleWord()) {
146 pVal = getMemory(RHS.getNumWords());
147 memcpy(pVal, RHS.pVal, RHS.getNumWords() * APINT_WORD_SIZE);
149 BitWidth = RHS.BitWidth;
150 return clearUnusedBits();
153 APInt& APInt::operator=(uint64_t RHS) {
158 memset(pVal+1, 0, (getNumWords() - 1) * APINT_WORD_SIZE);
160 return clearUnusedBits();
163 /// Profile - This method 'profiles' an APInt for use with FoldingSet.
164 void APInt::Profile(FoldingSetNodeID& ID) const {
165 ID.AddInteger(BitWidth);
167 if (isSingleWord()) {
172 unsigned NumWords = getNumWords();
173 for (unsigned i = 0; i < NumWords; ++i)
174 ID.AddInteger(pVal[i]);
177 /// add_1 - This function adds a single "digit" integer, y, to the multiple
178 /// "digit" integer array, x[]. x[] is modified to reflect the addition and
179 /// 1 is returned if there is a carry out, otherwise 0 is returned.
180 /// @returns the carry of the addition.
181 static bool add_1(uint64_t dest[], uint64_t x[], unsigned len, uint64_t y) {
182 for (unsigned i = 0; i < len; ++i) {
185 y = 1; // Carry one to next digit.
187 y = 0; // No need to carry so exit early
194 /// @brief Prefix increment operator. Increments the APInt by one.
195 APInt& APInt::operator++() {
199 add_1(pVal, pVal, getNumWords(), 1);
200 return clearUnusedBits();
203 /// sub_1 - This function subtracts a single "digit" (64-bit word), y, from
204 /// the multi-digit integer array, x[], propagating the borrowed 1 value until
205 /// no further borrowing is neeeded or it runs out of "digits" in x. The result
206 /// is 1 if "borrowing" exhausted the digits in x, or 0 if x was not exhausted.
207 /// In other words, if y > x then this function returns 1, otherwise 0.
208 /// @returns the borrow out of the subtraction
209 static bool sub_1(uint64_t x[], unsigned len, uint64_t y) {
210 for (unsigned i = 0; i < len; ++i) {
214 y = 1; // We have to "borrow 1" from next "digit"
216 y = 0; // No need to borrow
217 break; // Remaining digits are unchanged so exit early
223 /// @brief Prefix decrement operator. Decrements the APInt by one.
224 APInt& APInt::operator--() {
228 sub_1(pVal, getNumWords(), 1);
229 return clearUnusedBits();
232 /// add - This function adds the integer array x to the integer array Y and
233 /// places the result in dest.
234 /// @returns the carry out from the addition
235 /// @brief General addition of 64-bit integer arrays
236 static bool add(uint64_t *dest, const uint64_t *x, const uint64_t *y,
239 for (unsigned i = 0; i< len; ++i) {
240 uint64_t limit = std::min(x[i],y[i]); // must come first in case dest == x
241 dest[i] = x[i] + y[i] + carry;
242 carry = dest[i] < limit || (carry && dest[i] == limit);
247 /// Adds the RHS APint to this APInt.
248 /// @returns this, after addition of RHS.
249 /// @brief Addition assignment operator.
250 APInt& APInt::operator+=(const APInt& RHS) {
251 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
255 add(pVal, pVal, RHS.pVal, getNumWords());
257 return clearUnusedBits();
260 /// Subtracts the integer array y from the integer array x
261 /// @returns returns the borrow out.
262 /// @brief Generalized subtraction of 64-bit integer arrays.
263 static bool sub(uint64_t *dest, const uint64_t *x, const uint64_t *y,
266 for (unsigned i = 0; i < len; ++i) {
267 uint64_t x_tmp = borrow ? x[i] - 1 : x[i];
268 borrow = y[i] > x_tmp || (borrow && x[i] == 0);
269 dest[i] = x_tmp - y[i];
274 /// Subtracts the RHS APInt from this APInt
275 /// @returns this, after subtraction
276 /// @brief Subtraction assignment operator.
277 APInt& APInt::operator-=(const APInt& RHS) {
278 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
282 sub(pVal, pVal, RHS.pVal, getNumWords());
283 return clearUnusedBits();
286 /// Multiplies an integer array, x, by a uint64_t integer and places the result
288 /// @returns the carry out of the multiplication.
289 /// @brief Multiply a multi-digit APInt by a single digit (64-bit) integer.
290 static uint64_t mul_1(uint64_t dest[], uint64_t x[], unsigned len, uint64_t y) {
291 // Split y into high 32-bit part (hy) and low 32-bit part (ly)
292 uint64_t ly = y & 0xffffffffULL, hy = y >> 32;
295 // For each digit of x.
296 for (unsigned i = 0; i < len; ++i) {
297 // Split x into high and low words
298 uint64_t lx = x[i] & 0xffffffffULL;
299 uint64_t hx = x[i] >> 32;
300 // hasCarry - A flag to indicate if there is a carry to the next digit.
301 // hasCarry == 0, no carry
302 // hasCarry == 1, has carry
303 // hasCarry == 2, no carry and the calculation result == 0.
304 uint8_t hasCarry = 0;
305 dest[i] = carry + lx * ly;
306 // Determine if the add above introduces carry.
307 hasCarry = (dest[i] < carry) ? 1 : 0;
308 carry = hx * ly + (dest[i] >> 32) + (hasCarry ? (1ULL << 32) : 0);
309 // The upper limit of carry can be (2^32 - 1)(2^32 - 1) +
310 // (2^32 - 1) + 2^32 = 2^64.
311 hasCarry = (!carry && hasCarry) ? 1 : (!carry ? 2 : 0);
313 carry += (lx * hy) & 0xffffffffULL;
314 dest[i] = (carry << 32) | (dest[i] & 0xffffffffULL);
315 carry = (((!carry && hasCarry != 2) || hasCarry == 1) ? (1ULL << 32) : 0) +
316 (carry >> 32) + ((lx * hy) >> 32) + hx * hy;
321 /// Multiplies integer array x by integer array y and stores the result into
322 /// the integer array dest. Note that dest's size must be >= xlen + ylen.
323 /// @brief Generalized multiplicate of integer arrays.
324 static void mul(uint64_t dest[], uint64_t x[], unsigned xlen, uint64_t y[],
326 dest[xlen] = mul_1(dest, x, xlen, y[0]);
327 for (unsigned i = 1; i < ylen; ++i) {
328 uint64_t ly = y[i] & 0xffffffffULL, hy = y[i] >> 32;
329 uint64_t carry = 0, lx = 0, hx = 0;
330 for (unsigned j = 0; j < xlen; ++j) {
331 lx = x[j] & 0xffffffffULL;
333 // hasCarry - A flag to indicate if has carry.
334 // hasCarry == 0, no carry
335 // hasCarry == 1, has carry
336 // hasCarry == 2, no carry and the calculation result == 0.
337 uint8_t hasCarry = 0;
338 uint64_t resul = carry + lx * ly;
339 hasCarry = (resul < carry) ? 1 : 0;
340 carry = (hasCarry ? (1ULL << 32) : 0) + hx * ly + (resul >> 32);
341 hasCarry = (!carry && hasCarry) ? 1 : (!carry ? 2 : 0);
343 carry += (lx * hy) & 0xffffffffULL;
344 resul = (carry << 32) | (resul & 0xffffffffULL);
346 carry = (((!carry && hasCarry != 2) || hasCarry == 1) ? (1ULL << 32) : 0)+
347 (carry >> 32) + (dest[i+j] < resul ? 1 : 0) +
348 ((lx * hy) >> 32) + hx * hy;
350 dest[i+xlen] = carry;
354 APInt& APInt::operator*=(const APInt& RHS) {
355 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
356 if (isSingleWord()) {
362 // Get some bit facts about LHS and check for zero
363 unsigned lhsBits = getActiveBits();
364 unsigned lhsWords = !lhsBits ? 0 : whichWord(lhsBits - 1) + 1;
369 // Get some bit facts about RHS and check for zero
370 unsigned rhsBits = RHS.getActiveBits();
371 unsigned rhsWords = !rhsBits ? 0 : whichWord(rhsBits - 1) + 1;
378 // Allocate space for the result
379 unsigned destWords = rhsWords + lhsWords;
380 uint64_t *dest = getMemory(destWords);
382 // Perform the long multiply
383 mul(dest, pVal, lhsWords, RHS.pVal, rhsWords);
385 // Copy result back into *this
387 unsigned wordsToCopy = destWords >= getNumWords() ? getNumWords() : destWords;
388 memcpy(pVal, dest, wordsToCopy * APINT_WORD_SIZE);
391 // delete dest array and return
396 APInt& APInt::operator&=(const APInt& RHS) {
397 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
398 if (isSingleWord()) {
402 unsigned numWords = getNumWords();
403 for (unsigned i = 0; i < numWords; ++i)
404 pVal[i] &= RHS.pVal[i];
408 APInt& APInt::operator|=(const APInt& RHS) {
409 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
410 if (isSingleWord()) {
414 unsigned numWords = getNumWords();
415 for (unsigned i = 0; i < numWords; ++i)
416 pVal[i] |= RHS.pVal[i];
420 APInt& APInt::operator^=(const APInt& RHS) {
421 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
422 if (isSingleWord()) {
424 this->clearUnusedBits();
427 unsigned numWords = getNumWords();
428 for (unsigned i = 0; i < numWords; ++i)
429 pVal[i] ^= RHS.pVal[i];
430 return clearUnusedBits();
433 APInt APInt::AndSlowCase(const APInt& RHS) const {
434 unsigned numWords = getNumWords();
435 uint64_t* val = getMemory(numWords);
436 for (unsigned i = 0; i < numWords; ++i)
437 val[i] = pVal[i] & RHS.pVal[i];
438 return APInt(val, getBitWidth());
441 APInt APInt::OrSlowCase(const APInt& RHS) const {
442 unsigned numWords = getNumWords();
443 uint64_t *val = getMemory(numWords);
444 for (unsigned i = 0; i < numWords; ++i)
445 val[i] = pVal[i] | RHS.pVal[i];
446 return APInt(val, getBitWidth());
449 APInt APInt::XorSlowCase(const APInt& RHS) const {
450 unsigned numWords = getNumWords();
451 uint64_t *val = getMemory(numWords);
452 for (unsigned i = 0; i < numWords; ++i)
453 val[i] = pVal[i] ^ RHS.pVal[i];
455 // 0^0==1 so clear the high bits in case they got set.
456 return APInt(val, getBitWidth()).clearUnusedBits();
459 bool APInt::operator !() const {
463 for (unsigned i = 0; i < getNumWords(); ++i)
469 APInt APInt::operator*(const APInt& RHS) const {
470 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
472 return APInt(BitWidth, VAL * RHS.VAL);
478 APInt APInt::operator+(const APInt& RHS) const {
479 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
481 return APInt(BitWidth, VAL + RHS.VAL);
482 APInt Result(BitWidth, 0);
483 add(Result.pVal, this->pVal, RHS.pVal, getNumWords());
484 return Result.clearUnusedBits();
487 APInt APInt::operator-(const APInt& RHS) const {
488 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
490 return APInt(BitWidth, VAL - RHS.VAL);
491 APInt Result(BitWidth, 0);
492 sub(Result.pVal, this->pVal, RHS.pVal, getNumWords());
493 return Result.clearUnusedBits();
496 bool APInt::operator[](unsigned bitPosition) const {
497 assert(bitPosition < getBitWidth() && "Bit position out of bounds!");
498 return (maskBit(bitPosition) &
499 (isSingleWord() ? VAL : pVal[whichWord(bitPosition)])) != 0;
502 bool APInt::EqualSlowCase(const APInt& RHS) const {
503 // Get some facts about the number of bits used in the two operands.
504 unsigned n1 = getActiveBits();
505 unsigned n2 = RHS.getActiveBits();
507 // If the number of bits isn't the same, they aren't equal
511 // If the number of bits fits in a word, we only need to compare the low word.
512 if (n1 <= APINT_BITS_PER_WORD)
513 return pVal[0] == RHS.pVal[0];
515 // Otherwise, compare everything
516 for (int i = whichWord(n1 - 1); i >= 0; --i)
517 if (pVal[i] != RHS.pVal[i])
522 bool APInt::EqualSlowCase(uint64_t Val) const {
523 unsigned n = getActiveBits();
524 if (n <= APINT_BITS_PER_WORD)
525 return pVal[0] == Val;
530 bool APInt::ult(const APInt& RHS) const {
531 assert(BitWidth == RHS.BitWidth && "Bit widths must be same for comparison");
533 return VAL < RHS.VAL;
535 // Get active bit length of both operands
536 unsigned n1 = getActiveBits();
537 unsigned n2 = RHS.getActiveBits();
539 // If magnitude of LHS is less than RHS, return true.
543 // If magnitude of RHS is greather than LHS, return false.
547 // If they bot fit in a word, just compare the low order word
548 if (n1 <= APINT_BITS_PER_WORD && n2 <= APINT_BITS_PER_WORD)
549 return pVal[0] < RHS.pVal[0];
551 // Otherwise, compare all words
552 unsigned topWord = whichWord(std::max(n1,n2)-1);
553 for (int i = topWord; i >= 0; --i) {
554 if (pVal[i] > RHS.pVal[i])
556 if (pVal[i] < RHS.pVal[i])
562 bool APInt::slt(const APInt& RHS) const {
563 assert(BitWidth == RHS.BitWidth && "Bit widths must be same for comparison");
564 if (isSingleWord()) {
565 int64_t lhsSext = (int64_t(VAL) << (64-BitWidth)) >> (64-BitWidth);
566 int64_t rhsSext = (int64_t(RHS.VAL) << (64-BitWidth)) >> (64-BitWidth);
567 return lhsSext < rhsSext;
572 bool lhsNeg = isNegative();
573 bool rhsNeg = rhs.isNegative();
575 // Sign bit is set so perform two's complement to make it positive
580 // Sign bit is set so perform two's complement to make it positive
585 // Now we have unsigned values to compare so do the comparison if necessary
586 // based on the negativeness of the values.
598 void APInt::setBit(unsigned bitPosition) {
600 VAL |= maskBit(bitPosition);
602 pVal[whichWord(bitPosition)] |= maskBit(bitPosition);
605 /// Set the given bit to 0 whose position is given as "bitPosition".
606 /// @brief Set a given bit to 0.
607 void APInt::clearBit(unsigned bitPosition) {
609 VAL &= ~maskBit(bitPosition);
611 pVal[whichWord(bitPosition)] &= ~maskBit(bitPosition);
614 /// @brief Toggle every bit to its opposite value.
616 /// Toggle a given bit to its opposite value whose position is given
617 /// as "bitPosition".
618 /// @brief Toggles a given bit to its opposite value.
619 void APInt::flipBit(unsigned bitPosition) {
620 assert(bitPosition < BitWidth && "Out of the bit-width range!");
621 if ((*this)[bitPosition]) clearBit(bitPosition);
622 else setBit(bitPosition);
625 unsigned APInt::getBitsNeeded(StringRef str, uint8_t radix) {
626 assert(!str.empty() && "Invalid string length");
627 assert((radix == 10 || radix == 8 || radix == 16 || radix == 2 ||
629 "Radix should be 2, 8, 10, 16, or 36!");
631 size_t slen = str.size();
633 // Each computation below needs to know if it's negative.
634 StringRef::iterator p = str.begin();
635 unsigned isNegative = *p == '-';
636 if (*p == '-' || *p == '+') {
639 assert(slen && "String is only a sign, needs a value.");
642 // For radixes of power-of-two values, the bits required is accurately and
645 return slen + isNegative;
647 return slen * 3 + isNegative;
649 return slen * 4 + isNegative;
653 // This is grossly inefficient but accurate. We could probably do something
654 // with a computation of roughly slen*64/20 and then adjust by the value of
655 // the first few digits. But, I'm not sure how accurate that could be.
657 // Compute a sufficient number of bits that is always large enough but might
658 // be too large. This avoids the assertion in the constructor. This
659 // calculation doesn't work appropriately for the numbers 0-9, so just use 4
660 // bits in that case.
662 = radix == 10? (slen == 1 ? 4 : slen * 64/18)
663 : (slen == 1 ? 7 : slen * 16/3);
665 // Convert to the actual binary value.
666 APInt tmp(sufficient, StringRef(p, slen), radix);
668 // Compute how many bits are required. If the log is infinite, assume we need
670 unsigned log = tmp.logBase2();
671 if (log == (unsigned)-1) {
672 return isNegative + 1;
674 return isNegative + log + 1;
678 // From http://www.burtleburtle.net, byBob Jenkins.
679 // When targeting x86, both GCC and LLVM seem to recognize this as a
680 // rotate instruction.
681 #define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
683 // From http://www.burtleburtle.net, by Bob Jenkins.
686 a -= c; a ^= rot(c, 4); c += b; \
687 b -= a; b ^= rot(a, 6); a += c; \
688 c -= b; c ^= rot(b, 8); b += a; \
689 a -= c; a ^= rot(c,16); c += b; \
690 b -= a; b ^= rot(a,19); a += c; \
691 c -= b; c ^= rot(b, 4); b += a; \
694 // From http://www.burtleburtle.net, by Bob Jenkins.
695 #define final(a,b,c) \
697 c ^= b; c -= rot(b,14); \
698 a ^= c; a -= rot(c,11); \
699 b ^= a; b -= rot(a,25); \
700 c ^= b; c -= rot(b,16); \
701 a ^= c; a -= rot(c,4); \
702 b ^= a; b -= rot(a,14); \
703 c ^= b; c -= rot(b,24); \
706 // hashword() was adapted from http://www.burtleburtle.net, by Bob
707 // Jenkins. k is a pointer to an array of uint32_t values; length is
708 // the length of the key, in 32-bit chunks. This version only handles
709 // keys that are a multiple of 32 bits in size.
710 static inline uint32_t hashword(const uint64_t *k64, size_t length)
712 const uint32_t *k = reinterpret_cast<const uint32_t *>(k64);
715 /* Set up the internal state */
716 a = b = c = 0xdeadbeef + (((uint32_t)length)<<2);
718 /*------------------------------------------------- handle most of the key */
728 /*------------------------------------------- handle the last 3 uint32_t's */
729 switch (length) { /* all the case statements fall through */
734 case 0: /* case 0: nothing left to add */
737 /*------------------------------------------------------ report the result */
741 // hashword8() was adapted from http://www.burtleburtle.net, by Bob
742 // Jenkins. This computes a 32-bit hash from one 64-bit word. When
743 // targeting x86 (32 or 64 bit), both LLVM and GCC compile this
744 // function into about 35 instructions when inlined.
745 static inline uint32_t hashword8(const uint64_t k64)
748 a = b = c = 0xdeadbeef + 4;
750 a += k64 & 0xffffffff;
758 uint64_t APInt::getHashValue() const {
761 hash = hashword8(VAL);
763 hash = hashword(pVal, getNumWords()*2);
767 /// HiBits - This function returns the high "numBits" bits of this APInt.
768 APInt APInt::getHiBits(unsigned numBits) const {
769 return APIntOps::lshr(*this, BitWidth - numBits);
772 /// LoBits - This function returns the low "numBits" bits of this APInt.
773 APInt APInt::getLoBits(unsigned numBits) const {
774 return APIntOps::lshr(APIntOps::shl(*this, BitWidth - numBits),
778 unsigned APInt::countLeadingZerosSlowCase() const {
779 // Treat the most significand word differently because it might have
780 // meaningless bits set beyond the precision.
781 unsigned BitsInMSW = BitWidth % APINT_BITS_PER_WORD;
783 if (BitsInMSW) MSWMask = (integerPart(1) << BitsInMSW) - 1;
785 MSWMask = ~integerPart(0);
786 BitsInMSW = APINT_BITS_PER_WORD;
789 unsigned i = getNumWords();
790 integerPart MSW = pVal[i-1] & MSWMask;
792 return CountLeadingZeros_64(MSW) - (APINT_BITS_PER_WORD - BitsInMSW);
794 unsigned Count = BitsInMSW;
795 for (--i; i > 0u; --i) {
797 Count += APINT_BITS_PER_WORD;
799 Count += CountLeadingZeros_64(pVal[i-1]);
806 static unsigned countLeadingOnes_64(uint64_t V, unsigned skip) {
810 while (V && (V & (1ULL << 63))) {
817 unsigned APInt::countLeadingOnes() const {
819 return countLeadingOnes_64(VAL, APINT_BITS_PER_WORD - BitWidth);
821 unsigned highWordBits = BitWidth % APINT_BITS_PER_WORD;
824 highWordBits = APINT_BITS_PER_WORD;
827 shift = APINT_BITS_PER_WORD - highWordBits;
829 int i = getNumWords() - 1;
830 unsigned Count = countLeadingOnes_64(pVal[i], shift);
831 if (Count == highWordBits) {
832 for (i--; i >= 0; --i) {
833 if (pVal[i] == -1ULL)
834 Count += APINT_BITS_PER_WORD;
836 Count += countLeadingOnes_64(pVal[i], 0);
844 unsigned APInt::countTrailingZeros() const {
846 return std::min(unsigned(CountTrailingZeros_64(VAL)), BitWidth);
849 for (; i < getNumWords() && pVal[i] == 0; ++i)
850 Count += APINT_BITS_PER_WORD;
851 if (i < getNumWords())
852 Count += CountTrailingZeros_64(pVal[i]);
853 return std::min(Count, BitWidth);
856 unsigned APInt::countTrailingOnesSlowCase() const {
859 for (; i < getNumWords() && pVal[i] == -1ULL; ++i)
860 Count += APINT_BITS_PER_WORD;
861 if (i < getNumWords())
862 Count += CountTrailingOnes_64(pVal[i]);
863 return std::min(Count, BitWidth);
866 unsigned APInt::countPopulationSlowCase() const {
868 for (unsigned i = 0; i < getNumWords(); ++i)
869 Count += CountPopulation_64(pVal[i]);
873 /// Perform a logical right-shift from Src to Dst, which must be equal or
874 /// non-overlapping, of Words words, by Shift, which must be less than 64.
875 static void lshrNear(uint64_t *Dst, uint64_t *Src, unsigned Words,
878 for (int I = Words - 1; I >= 0; --I) {
879 uint64_t Tmp = Src[I];
880 Dst[I] = (Tmp >> Shift) | Carry;
881 Carry = Tmp << (64 - Shift);
885 APInt APInt::byteSwap() const {
886 assert(BitWidth >= 16 && BitWidth % 16 == 0 && "Cannot byteswap!");
888 return APInt(BitWidth, ByteSwap_16(uint16_t(VAL)));
890 return APInt(BitWidth, ByteSwap_32(unsigned(VAL)));
891 if (BitWidth == 48) {
892 unsigned Tmp1 = unsigned(VAL >> 16);
893 Tmp1 = ByteSwap_32(Tmp1);
894 uint16_t Tmp2 = uint16_t(VAL);
895 Tmp2 = ByteSwap_16(Tmp2);
896 return APInt(BitWidth, (uint64_t(Tmp2) << 32) | Tmp1);
899 return APInt(BitWidth, ByteSwap_64(VAL));
901 APInt Result(getNumWords() * APINT_BITS_PER_WORD, 0);
902 for (unsigned I = 0, N = getNumWords(); I != N; ++I)
903 Result.pVal[I] = ByteSwap_64(pVal[N - I - 1]);
904 if (Result.BitWidth != BitWidth) {
905 lshrNear(Result.pVal, Result.pVal, getNumWords(),
906 Result.BitWidth - BitWidth);
907 Result.BitWidth = BitWidth;
912 APInt llvm::APIntOps::GreatestCommonDivisor(const APInt& API1,
914 APInt A = API1, B = API2;
917 B = APIntOps::urem(A, B);
923 APInt llvm::APIntOps::RoundDoubleToAPInt(double Double, unsigned width) {
930 // Get the sign bit from the highest order bit
931 bool isNeg = T.I >> 63;
933 // Get the 11-bit exponent and adjust for the 1023 bit bias
934 int64_t exp = ((T.I >> 52) & 0x7ff) - 1023;
936 // If the exponent is negative, the value is < 0 so just return 0.
938 return APInt(width, 0u);
940 // Extract the mantissa by clearing the top 12 bits (sign + exponent).
941 uint64_t mantissa = (T.I & (~0ULL >> 12)) | 1ULL << 52;
943 // If the exponent doesn't shift all bits out of the mantissa
945 return isNeg ? -APInt(width, mantissa >> (52 - exp)) :
946 APInt(width, mantissa >> (52 - exp));
948 // If the client didn't provide enough bits for us to shift the mantissa into
949 // then the result is undefined, just return 0
950 if (width <= exp - 52)
951 return APInt(width, 0);
953 // Otherwise, we have to shift the mantissa bits up to the right location
954 APInt Tmp(width, mantissa);
955 Tmp = Tmp.shl((unsigned)exp - 52);
956 return isNeg ? -Tmp : Tmp;
959 /// RoundToDouble - This function converts this APInt to a double.
960 /// The layout for double is as following (IEEE Standard 754):
961 /// --------------------------------------
962 /// | Sign Exponent Fraction Bias |
963 /// |-------------------------------------- |
964 /// | 1[63] 11[62-52] 52[51-00] 1023 |
965 /// --------------------------------------
966 double APInt::roundToDouble(bool isSigned) const {
968 // Handle the simple case where the value is contained in one uint64_t.
969 // It is wrong to optimize getWord(0) to VAL; there might be more than one word.
970 if (isSingleWord() || getActiveBits() <= APINT_BITS_PER_WORD) {
972 int64_t sext = (int64_t(getWord(0)) << (64-BitWidth)) >> (64-BitWidth);
975 return double(getWord(0));
978 // Determine if the value is negative.
979 bool isNeg = isSigned ? (*this)[BitWidth-1] : false;
981 // Construct the absolute value if we're negative.
982 APInt Tmp(isNeg ? -(*this) : (*this));
984 // Figure out how many bits we're using.
985 unsigned n = Tmp.getActiveBits();
987 // The exponent (without bias normalization) is just the number of bits
988 // we are using. Note that the sign bit is gone since we constructed the
992 // Return infinity for exponent overflow
994 if (!isSigned || !isNeg)
995 return std::numeric_limits<double>::infinity();
997 return -std::numeric_limits<double>::infinity();
999 exp += 1023; // Increment for 1023 bias
1001 // Number of bits in mantissa is 52. To obtain the mantissa value, we must
1002 // extract the high 52 bits from the correct words in pVal.
1004 unsigned hiWord = whichWord(n-1);
1006 mantissa = Tmp.pVal[0];
1008 mantissa >>= n - 52; // shift down, we want the top 52 bits.
1010 assert(hiWord > 0 && "huh?");
1011 uint64_t hibits = Tmp.pVal[hiWord] << (52 - n % APINT_BITS_PER_WORD);
1012 uint64_t lobits = Tmp.pVal[hiWord-1] >> (11 + n % APINT_BITS_PER_WORD);
1013 mantissa = hibits | lobits;
1016 // The leading bit of mantissa is implicit, so get rid of it.
1017 uint64_t sign = isNeg ? (1ULL << (APINT_BITS_PER_WORD - 1)) : 0;
1022 T.I = sign | (exp << 52) | mantissa;
1026 // Truncate to new width.
1027 APInt APInt::trunc(unsigned width) const {
1028 assert(width < BitWidth && "Invalid APInt Truncate request");
1029 assert(width && "Can't truncate to 0 bits");
1031 if (width <= APINT_BITS_PER_WORD)
1032 return APInt(width, getRawData()[0]);
1034 APInt Result(getMemory(getNumWords(width)), width);
1038 for (i = 0; i != width / APINT_BITS_PER_WORD; i++)
1039 Result.pVal[i] = pVal[i];
1041 // Truncate and copy any partial word.
1042 unsigned bits = (0 - width) % APINT_BITS_PER_WORD;
1044 Result.pVal[i] = pVal[i] << bits >> bits;
1049 // Sign extend to a new width.
1050 APInt APInt::sext(unsigned width) const {
1051 assert(width > BitWidth && "Invalid APInt SignExtend request");
1053 if (width <= APINT_BITS_PER_WORD) {
1054 uint64_t val = VAL << (APINT_BITS_PER_WORD - BitWidth);
1055 val = (int64_t)val >> (width - BitWidth);
1056 return APInt(width, val >> (APINT_BITS_PER_WORD - width));
1059 APInt Result(getMemory(getNumWords(width)), width);
1064 for (i = 0; i != BitWidth / APINT_BITS_PER_WORD; i++) {
1065 word = getRawData()[i];
1066 Result.pVal[i] = word;
1069 // Read and sign-extend any partial word.
1070 unsigned bits = (0 - BitWidth) % APINT_BITS_PER_WORD;
1072 word = (int64_t)getRawData()[i] << bits >> bits;
1074 word = (int64_t)word >> (APINT_BITS_PER_WORD - 1);
1076 // Write remaining full words.
1077 for (; i != width / APINT_BITS_PER_WORD; i++) {
1078 Result.pVal[i] = word;
1079 word = (int64_t)word >> (APINT_BITS_PER_WORD - 1);
1082 // Write any partial word.
1083 bits = (0 - width) % APINT_BITS_PER_WORD;
1085 Result.pVal[i] = word << bits >> bits;
1090 // Zero extend to a new width.
1091 APInt APInt::zext(unsigned width) const {
1092 assert(width > BitWidth && "Invalid APInt ZeroExtend request");
1094 if (width <= APINT_BITS_PER_WORD)
1095 return APInt(width, VAL);
1097 APInt Result(getMemory(getNumWords(width)), width);
1101 for (i = 0; i != getNumWords(); i++)
1102 Result.pVal[i] = getRawData()[i];
1104 // Zero remaining words.
1105 memset(&Result.pVal[i], 0, (Result.getNumWords() - i) * APINT_WORD_SIZE);
1110 APInt APInt::zextOrTrunc(unsigned width) const {
1111 if (BitWidth < width)
1113 if (BitWidth > width)
1114 return trunc(width);
1118 APInt APInt::sextOrTrunc(unsigned width) const {
1119 if (BitWidth < width)
1121 if (BitWidth > width)
1122 return trunc(width);
1126 /// Arithmetic right-shift this APInt by shiftAmt.
1127 /// @brief Arithmetic right-shift function.
1128 APInt APInt::ashr(const APInt &shiftAmt) const {
1129 return ashr((unsigned)shiftAmt.getLimitedValue(BitWidth));
1132 /// Arithmetic right-shift this APInt by shiftAmt.
1133 /// @brief Arithmetic right-shift function.
1134 APInt APInt::ashr(unsigned shiftAmt) const {
1135 assert(shiftAmt <= BitWidth && "Invalid shift amount");
1136 // Handle a degenerate case
1140 // Handle single word shifts with built-in ashr
1141 if (isSingleWord()) {
1142 if (shiftAmt == BitWidth)
1143 return APInt(BitWidth, 0); // undefined
1145 unsigned SignBit = APINT_BITS_PER_WORD - BitWidth;
1146 return APInt(BitWidth,
1147 (((int64_t(VAL) << SignBit) >> SignBit) >> shiftAmt));
1151 // If all the bits were shifted out, the result is, technically, undefined.
1152 // We return -1 if it was negative, 0 otherwise. We check this early to avoid
1153 // issues in the algorithm below.
1154 if (shiftAmt == BitWidth) {
1156 return APInt(BitWidth, -1ULL, true);
1158 return APInt(BitWidth, 0);
1161 // Create some space for the result.
1162 uint64_t * val = new uint64_t[getNumWords()];
1164 // Compute some values needed by the following shift algorithms
1165 unsigned wordShift = shiftAmt % APINT_BITS_PER_WORD; // bits to shift per word
1166 unsigned offset = shiftAmt / APINT_BITS_PER_WORD; // word offset for shift
1167 unsigned breakWord = getNumWords() - 1 - offset; // last word affected
1168 unsigned bitsInWord = whichBit(BitWidth); // how many bits in last word?
1169 if (bitsInWord == 0)
1170 bitsInWord = APINT_BITS_PER_WORD;
1172 // If we are shifting whole words, just move whole words
1173 if (wordShift == 0) {
1174 // Move the words containing significant bits
1175 for (unsigned i = 0; i <= breakWord; ++i)
1176 val[i] = pVal[i+offset]; // move whole word
1178 // Adjust the top significant word for sign bit fill, if negative
1180 if (bitsInWord < APINT_BITS_PER_WORD)
1181 val[breakWord] |= ~0ULL << bitsInWord; // set high bits
1183 // Shift the low order words
1184 for (unsigned i = 0; i < breakWord; ++i) {
1185 // This combines the shifted corresponding word with the low bits from
1186 // the next word (shifted into this word's high bits).
1187 val[i] = (pVal[i+offset] >> wordShift) |
1188 (pVal[i+offset+1] << (APINT_BITS_PER_WORD - wordShift));
1191 // Shift the break word. In this case there are no bits from the next word
1192 // to include in this word.
1193 val[breakWord] = pVal[breakWord+offset] >> wordShift;
1195 // Deal with sign extenstion in the break word, and possibly the word before
1198 if (wordShift > bitsInWord) {
1201 ~0ULL << (APINT_BITS_PER_WORD - (wordShift - bitsInWord));
1202 val[breakWord] |= ~0ULL;
1204 val[breakWord] |= (~0ULL << (bitsInWord - wordShift));
1208 // Remaining words are 0 or -1, just assign them.
1209 uint64_t fillValue = (isNegative() ? -1ULL : 0);
1210 for (unsigned i = breakWord+1; i < getNumWords(); ++i)
1212 return APInt(val, BitWidth).clearUnusedBits();
1215 /// Logical right-shift this APInt by shiftAmt.
1216 /// @brief Logical right-shift function.
1217 APInt APInt::lshr(const APInt &shiftAmt) const {
1218 return lshr((unsigned)shiftAmt.getLimitedValue(BitWidth));
1221 /// Logical right-shift this APInt by shiftAmt.
1222 /// @brief Logical right-shift function.
1223 APInt APInt::lshr(unsigned shiftAmt) const {
1224 if (isSingleWord()) {
1225 if (shiftAmt == BitWidth)
1226 return APInt(BitWidth, 0);
1228 return APInt(BitWidth, this->VAL >> shiftAmt);
1231 // If all the bits were shifted out, the result is 0. This avoids issues
1232 // with shifting by the size of the integer type, which produces undefined
1233 // results. We define these "undefined results" to always be 0.
1234 if (shiftAmt == BitWidth)
1235 return APInt(BitWidth, 0);
1237 // If none of the bits are shifted out, the result is *this. This avoids
1238 // issues with shifting by the size of the integer type, which produces
1239 // undefined results in the code below. This is also an optimization.
1243 // Create some space for the result.
1244 uint64_t * val = new uint64_t[getNumWords()];
1246 // If we are shifting less than a word, compute the shift with a simple carry
1247 if (shiftAmt < APINT_BITS_PER_WORD) {
1248 lshrNear(val, pVal, getNumWords(), shiftAmt);
1249 return APInt(val, BitWidth).clearUnusedBits();
1252 // Compute some values needed by the remaining shift algorithms
1253 unsigned wordShift = shiftAmt % APINT_BITS_PER_WORD;
1254 unsigned offset = shiftAmt / APINT_BITS_PER_WORD;
1256 // If we are shifting whole words, just move whole words
1257 if (wordShift == 0) {
1258 for (unsigned i = 0; i < getNumWords() - offset; ++i)
1259 val[i] = pVal[i+offset];
1260 for (unsigned i = getNumWords()-offset; i < getNumWords(); i++)
1262 return APInt(val,BitWidth).clearUnusedBits();
1265 // Shift the low order words
1266 unsigned breakWord = getNumWords() - offset -1;
1267 for (unsigned i = 0; i < breakWord; ++i)
1268 val[i] = (pVal[i+offset] >> wordShift) |
1269 (pVal[i+offset+1] << (APINT_BITS_PER_WORD - wordShift));
1270 // Shift the break word.
1271 val[breakWord] = pVal[breakWord+offset] >> wordShift;
1273 // Remaining words are 0
1274 for (unsigned i = breakWord+1; i < getNumWords(); ++i)
1276 return APInt(val, BitWidth).clearUnusedBits();
1279 /// Left-shift this APInt by shiftAmt.
1280 /// @brief Left-shift function.
1281 APInt APInt::shl(const APInt &shiftAmt) const {
1282 // It's undefined behavior in C to shift by BitWidth or greater.
1283 return shl((unsigned)shiftAmt.getLimitedValue(BitWidth));
1286 APInt APInt::shlSlowCase(unsigned shiftAmt) const {
1287 // If all the bits were shifted out, the result is 0. This avoids issues
1288 // with shifting by the size of the integer type, which produces undefined
1289 // results. We define these "undefined results" to always be 0.
1290 if (shiftAmt == BitWidth)
1291 return APInt(BitWidth, 0);
1293 // If none of the bits are shifted out, the result is *this. This avoids a
1294 // lshr by the words size in the loop below which can produce incorrect
1295 // results. It also avoids the expensive computation below for a common case.
1299 // Create some space for the result.
1300 uint64_t * val = new uint64_t[getNumWords()];
1302 // If we are shifting less than a word, do it the easy way
1303 if (shiftAmt < APINT_BITS_PER_WORD) {
1305 for (unsigned i = 0; i < getNumWords(); i++) {
1306 val[i] = pVal[i] << shiftAmt | carry;
1307 carry = pVal[i] >> (APINT_BITS_PER_WORD - shiftAmt);
1309 return APInt(val, BitWidth).clearUnusedBits();
1312 // Compute some values needed by the remaining shift algorithms
1313 unsigned wordShift = shiftAmt % APINT_BITS_PER_WORD;
1314 unsigned offset = shiftAmt / APINT_BITS_PER_WORD;
1316 // If we are shifting whole words, just move whole words
1317 if (wordShift == 0) {
1318 for (unsigned i = 0; i < offset; i++)
1320 for (unsigned i = offset; i < getNumWords(); i++)
1321 val[i] = pVal[i-offset];
1322 return APInt(val,BitWidth).clearUnusedBits();
1325 // Copy whole words from this to Result.
1326 unsigned i = getNumWords() - 1;
1327 for (; i > offset; --i)
1328 val[i] = pVal[i-offset] << wordShift |
1329 pVal[i-offset-1] >> (APINT_BITS_PER_WORD - wordShift);
1330 val[offset] = pVal[0] << wordShift;
1331 for (i = 0; i < offset; ++i)
1333 return APInt(val, BitWidth).clearUnusedBits();
1336 APInt APInt::rotl(const APInt &rotateAmt) const {
1337 return rotl((unsigned)rotateAmt.getLimitedValue(BitWidth));
1340 APInt APInt::rotl(unsigned rotateAmt) const {
1343 // Don't get too fancy, just use existing shift/or facilities
1347 lo.lshr(BitWidth - rotateAmt);
1351 APInt APInt::rotr(const APInt &rotateAmt) const {
1352 return rotr((unsigned)rotateAmt.getLimitedValue(BitWidth));
1355 APInt APInt::rotr(unsigned rotateAmt) const {
1358 // Don't get too fancy, just use existing shift/or facilities
1362 hi.shl(BitWidth - rotateAmt);
1366 // Square Root - this method computes and returns the square root of "this".
1367 // Three mechanisms are used for computation. For small values (<= 5 bits),
1368 // a table lookup is done. This gets some performance for common cases. For
1369 // values using less than 52 bits, the value is converted to double and then
1370 // the libc sqrt function is called. The result is rounded and then converted
1371 // back to a uint64_t which is then used to construct the result. Finally,
1372 // the Babylonian method for computing square roots is used.
1373 APInt APInt::sqrt() const {
1375 // Determine the magnitude of the value.
1376 unsigned magnitude = getActiveBits();
1378 // Use a fast table for some small values. This also gets rid of some
1379 // rounding errors in libc sqrt for small values.
1380 if (magnitude <= 5) {
1381 static const uint8_t results[32] = {
1384 /* 3- 6 */ 2, 2, 2, 2,
1385 /* 7-12 */ 3, 3, 3, 3, 3, 3,
1386 /* 13-20 */ 4, 4, 4, 4, 4, 4, 4, 4,
1387 /* 21-30 */ 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
1390 return APInt(BitWidth, results[ (isSingleWord() ? VAL : pVal[0]) ]);
1393 // If the magnitude of the value fits in less than 52 bits (the precision of
1394 // an IEEE double precision floating point value), then we can use the
1395 // libc sqrt function which will probably use a hardware sqrt computation.
1396 // This should be faster than the algorithm below.
1397 if (magnitude < 52) {
1399 return APInt(BitWidth,
1400 uint64_t(::round(::sqrt(double(isSingleWord()?VAL:pVal[0])))));
1402 return APInt(BitWidth,
1403 uint64_t(::sqrt(double(isSingleWord()?VAL:pVal[0])) + 0.5));
1407 // Okay, all the short cuts are exhausted. We must compute it. The following
1408 // is a classical Babylonian method for computing the square root. This code
1409 // was adapted to APINt from a wikipedia article on such computations.
1410 // See http://www.wikipedia.org/ and go to the page named
1411 // Calculate_an_integer_square_root.
1412 unsigned nbits = BitWidth, i = 4;
1413 APInt testy(BitWidth, 16);
1414 APInt x_old(BitWidth, 1);
1415 APInt x_new(BitWidth, 0);
1416 APInt two(BitWidth, 2);
1418 // Select a good starting value using binary logarithms.
1419 for (;; i += 2, testy = testy.shl(2))
1420 if (i >= nbits || this->ule(testy)) {
1421 x_old = x_old.shl(i / 2);
1425 // Use the Babylonian method to arrive at the integer square root:
1427 x_new = (this->udiv(x_old) + x_old).udiv(two);
1428 if (x_old.ule(x_new))
1433 // Make sure we return the closest approximation
1434 // NOTE: The rounding calculation below is correct. It will produce an
1435 // off-by-one discrepancy with results from pari/gp. That discrepancy has been
1436 // determined to be a rounding issue with pari/gp as it begins to use a
1437 // floating point representation after 192 bits. There are no discrepancies
1438 // between this algorithm and pari/gp for bit widths < 192 bits.
1439 APInt square(x_old * x_old);
1440 APInt nextSquare((x_old + 1) * (x_old +1));
1441 if (this->ult(square))
1443 assert(this->ule(nextSquare) && "Error in APInt::sqrt computation");
1444 APInt midpoint((nextSquare - square).udiv(two));
1445 APInt offset(*this - square);
1446 if (offset.ult(midpoint))
1451 /// Computes the multiplicative inverse of this APInt for a given modulo. The
1452 /// iterative extended Euclidean algorithm is used to solve for this value,
1453 /// however we simplify it to speed up calculating only the inverse, and take
1454 /// advantage of div+rem calculations. We also use some tricks to avoid copying
1455 /// (potentially large) APInts around.
1456 APInt APInt::multiplicativeInverse(const APInt& modulo) const {
1457 assert(ult(modulo) && "This APInt must be smaller than the modulo");
1459 // Using the properties listed at the following web page (accessed 06/21/08):
1460 // http://www.numbertheory.org/php/euclid.html
1461 // (especially the properties numbered 3, 4 and 9) it can be proved that
1462 // BitWidth bits suffice for all the computations in the algorithm implemented
1463 // below. More precisely, this number of bits suffice if the multiplicative
1464 // inverse exists, but may not suffice for the general extended Euclidean
1467 APInt r[2] = { modulo, *this };
1468 APInt t[2] = { APInt(BitWidth, 0), APInt(BitWidth, 1) };
1469 APInt q(BitWidth, 0);
1472 for (i = 0; r[i^1] != 0; i ^= 1) {
1473 // An overview of the math without the confusing bit-flipping:
1474 // q = r[i-2] / r[i-1]
1475 // r[i] = r[i-2] % r[i-1]
1476 // t[i] = t[i-2] - t[i-1] * q
1477 udivrem(r[i], r[i^1], q, r[i]);
1481 // If this APInt and the modulo are not coprime, there is no multiplicative
1482 // inverse, so return 0. We check this by looking at the next-to-last
1483 // remainder, which is the gcd(*this,modulo) as calculated by the Euclidean
1486 return APInt(BitWidth, 0);
1488 // The next-to-last t is the multiplicative inverse. However, we are
1489 // interested in a positive inverse. Calcuate a positive one from a negative
1490 // one if necessary. A simple addition of the modulo suffices because
1491 // abs(t[i]) is known to be less than *this/2 (see the link above).
1492 return t[i].isNegative() ? t[i] + modulo : t[i];
1495 /// Calculate the magic numbers required to implement a signed integer division
1496 /// by a constant as a sequence of multiplies, adds and shifts. Requires that
1497 /// the divisor not be 0, 1, or -1. Taken from "Hacker's Delight", Henry S.
1498 /// Warren, Jr., chapter 10.
1499 APInt::ms APInt::magic() const {
1500 const APInt& d = *this;
1502 APInt ad, anc, delta, q1, r1, q2, r2, t;
1503 APInt signedMin = APInt::getSignedMinValue(d.getBitWidth());
1507 t = signedMin + (d.lshr(d.getBitWidth() - 1));
1508 anc = t - 1 - t.urem(ad); // absolute value of nc
1509 p = d.getBitWidth() - 1; // initialize p
1510 q1 = signedMin.udiv(anc); // initialize q1 = 2p/abs(nc)
1511 r1 = signedMin - q1*anc; // initialize r1 = rem(2p,abs(nc))
1512 q2 = signedMin.udiv(ad); // initialize q2 = 2p/abs(d)
1513 r2 = signedMin - q2*ad; // initialize r2 = rem(2p,abs(d))
1516 q1 = q1<<1; // update q1 = 2p/abs(nc)
1517 r1 = r1<<1; // update r1 = rem(2p/abs(nc))
1518 if (r1.uge(anc)) { // must be unsigned comparison
1522 q2 = q2<<1; // update q2 = 2p/abs(d)
1523 r2 = r2<<1; // update r2 = rem(2p/abs(d))
1524 if (r2.uge(ad)) { // must be unsigned comparison
1529 } while (q1.ult(delta) || (q1 == delta && r1 == 0));
1532 if (d.isNegative()) mag.m = -mag.m; // resulting magic number
1533 mag.s = p - d.getBitWidth(); // resulting shift
1537 /// Calculate the magic numbers required to implement an unsigned integer
1538 /// division by a constant as a sequence of multiplies, adds and shifts.
1539 /// Requires that the divisor not be 0. Taken from "Hacker's Delight", Henry
1540 /// S. Warren, Jr., chapter 10.
1541 /// LeadingZeros can be used to simplify the calculation if the upper bits
1542 /// of the divided value are known zero.
1543 APInt::mu APInt::magicu(unsigned LeadingZeros) const {
1544 const APInt& d = *this;
1546 APInt nc, delta, q1, r1, q2, r2;
1548 magu.a = 0; // initialize "add" indicator
1549 APInt allOnes = APInt::getAllOnesValue(d.getBitWidth()).lshr(LeadingZeros);
1550 APInt signedMin = APInt::getSignedMinValue(d.getBitWidth());
1551 APInt signedMax = APInt::getSignedMaxValue(d.getBitWidth());
1553 nc = allOnes - (-d).urem(d);
1554 p = d.getBitWidth() - 1; // initialize p
1555 q1 = signedMin.udiv(nc); // initialize q1 = 2p/nc
1556 r1 = signedMin - q1*nc; // initialize r1 = rem(2p,nc)
1557 q2 = signedMax.udiv(d); // initialize q2 = (2p-1)/d
1558 r2 = signedMax - q2*d; // initialize r2 = rem((2p-1),d)
1561 if (r1.uge(nc - r1)) {
1562 q1 = q1 + q1 + 1; // update q1
1563 r1 = r1 + r1 - nc; // update r1
1566 q1 = q1+q1; // update q1
1567 r1 = r1+r1; // update r1
1569 if ((r2 + 1).uge(d - r2)) {
1570 if (q2.uge(signedMax)) magu.a = 1;
1571 q2 = q2+q2 + 1; // update q2
1572 r2 = r2+r2 + 1 - d; // update r2
1575 if (q2.uge(signedMin)) magu.a = 1;
1576 q2 = q2+q2; // update q2
1577 r2 = r2+r2 + 1; // update r2
1580 } while (p < d.getBitWidth()*2 &&
1581 (q1.ult(delta) || (q1 == delta && r1 == 0)));
1582 magu.m = q2 + 1; // resulting magic number
1583 magu.s = p - d.getBitWidth(); // resulting shift
1587 /// Implementation of Knuth's Algorithm D (Division of nonnegative integers)
1588 /// from "Art of Computer Programming, Volume 2", section 4.3.1, p. 272. The
1589 /// variables here have the same names as in the algorithm. Comments explain
1590 /// the algorithm and any deviation from it.
1591 static void KnuthDiv(unsigned *u, unsigned *v, unsigned *q, unsigned* r,
1592 unsigned m, unsigned n) {
1593 assert(u && "Must provide dividend");
1594 assert(v && "Must provide divisor");
1595 assert(q && "Must provide quotient");
1596 assert(u != v && u != q && v != q && "Must us different memory");
1597 assert(n>1 && "n must be > 1");
1599 // Knuth uses the value b as the base of the number system. In our case b
1600 // is 2^31 so we just set it to -1u.
1601 uint64_t b = uint64_t(1) << 32;
1604 DEBUG(dbgs() << "KnuthDiv: m=" << m << " n=" << n << '\n');
1605 DEBUG(dbgs() << "KnuthDiv: original:");
1606 DEBUG(for (int i = m+n; i >=0; i--) dbgs() << " " << u[i]);
1607 DEBUG(dbgs() << " by");
1608 DEBUG(for (int i = n; i >0; i--) dbgs() << " " << v[i-1]);
1609 DEBUG(dbgs() << '\n');
1611 // D1. [Normalize.] Set d = b / (v[n-1] + 1) and multiply all the digits of
1612 // u and v by d. Note that we have taken Knuth's advice here to use a power
1613 // of 2 value for d such that d * v[n-1] >= b/2 (b is the base). A power of
1614 // 2 allows us to shift instead of multiply and it is easy to determine the
1615 // shift amount from the leading zeros. We are basically normalizing the u
1616 // and v so that its high bits are shifted to the top of v's range without
1617 // overflow. Note that this can require an extra word in u so that u must
1618 // be of length m+n+1.
1619 unsigned shift = CountLeadingZeros_32(v[n-1]);
1620 unsigned v_carry = 0;
1621 unsigned u_carry = 0;
1623 for (unsigned i = 0; i < m+n; ++i) {
1624 unsigned u_tmp = u[i] >> (32 - shift);
1625 u[i] = (u[i] << shift) | u_carry;
1628 for (unsigned i = 0; i < n; ++i) {
1629 unsigned v_tmp = v[i] >> (32 - shift);
1630 v[i] = (v[i] << shift) | v_carry;
1636 DEBUG(dbgs() << "KnuthDiv: normal:");
1637 DEBUG(for (int i = m+n; i >=0; i--) dbgs() << " " << u[i]);
1638 DEBUG(dbgs() << " by");
1639 DEBUG(for (int i = n; i >0; i--) dbgs() << " " << v[i-1]);
1640 DEBUG(dbgs() << '\n');
1643 // D2. [Initialize j.] Set j to m. This is the loop counter over the places.
1646 DEBUG(dbgs() << "KnuthDiv: quotient digit #" << j << '\n');
1647 // D3. [Calculate q'.].
1648 // Set qp = (u[j+n]*b + u[j+n-1]) / v[n-1]. (qp=qprime=q')
1649 // Set rp = (u[j+n]*b + u[j+n-1]) % v[n-1]. (rp=rprime=r')
1650 // Now test if qp == b or qp*v[n-2] > b*rp + u[j+n-2]; if so, decrease
1651 // qp by 1, inrease rp by v[n-1], and repeat this test if rp < b. The test
1652 // on v[n-2] determines at high speed most of the cases in which the trial
1653 // value qp is one too large, and it eliminates all cases where qp is two
1655 uint64_t dividend = ((uint64_t(u[j+n]) << 32) + u[j+n-1]);
1656 DEBUG(dbgs() << "KnuthDiv: dividend == " << dividend << '\n');
1657 uint64_t qp = dividend / v[n-1];
1658 uint64_t rp = dividend % v[n-1];
1659 if (qp == b || qp*v[n-2] > b*rp + u[j+n-2]) {
1662 if (rp < b && (qp == b || qp*v[n-2] > b*rp + u[j+n-2]))
1665 DEBUG(dbgs() << "KnuthDiv: qp == " << qp << ", rp == " << rp << '\n');
1667 // D4. [Multiply and subtract.] Replace (u[j+n]u[j+n-1]...u[j]) with
1668 // (u[j+n]u[j+n-1]..u[j]) - qp * (v[n-1]...v[1]v[0]). This computation
1669 // consists of a simple multiplication by a one-place number, combined with
1672 for (unsigned i = 0; i < n; ++i) {
1673 uint64_t u_tmp = uint64_t(u[j+i]) | (uint64_t(u[j+i+1]) << 32);
1674 uint64_t subtrahend = uint64_t(qp) * uint64_t(v[i]);
1675 bool borrow = subtrahend > u_tmp;
1676 DEBUG(dbgs() << "KnuthDiv: u_tmp == " << u_tmp
1677 << ", subtrahend == " << subtrahend
1678 << ", borrow = " << borrow << '\n');
1680 uint64_t result = u_tmp - subtrahend;
1682 u[k++] = (unsigned)(result & (b-1)); // subtract low word
1683 u[k++] = (unsigned)(result >> 32); // subtract high word
1684 while (borrow && k <= m+n) { // deal with borrow to the left
1690 DEBUG(dbgs() << "KnuthDiv: u[j+i] == " << u[j+i] << ", u[j+i+1] == " <<
1693 DEBUG(dbgs() << "KnuthDiv: after subtraction:");
1694 DEBUG(for (int i = m+n; i >=0; i--) dbgs() << " " << u[i]);
1695 DEBUG(dbgs() << '\n');
1696 // The digits (u[j+n]...u[j]) should be kept positive; if the result of
1697 // this step is actually negative, (u[j+n]...u[j]) should be left as the
1698 // true value plus b**(n+1), namely as the b's complement of
1699 // the true value, and a "borrow" to the left should be remembered.
1702 bool carry = true; // true because b's complement is "complement + 1"
1703 for (unsigned i = 0; i <= m+n; ++i) {
1704 u[i] = ~u[i] + carry; // b's complement
1705 carry = carry && u[i] == 0;
1708 DEBUG(dbgs() << "KnuthDiv: after complement:");
1709 DEBUG(for (int i = m+n; i >=0; i--) dbgs() << " " << u[i]);
1710 DEBUG(dbgs() << '\n');
1712 // D5. [Test remainder.] Set q[j] = qp. If the result of step D4 was
1713 // negative, go to step D6; otherwise go on to step D7.
1714 q[j] = (unsigned)qp;
1716 // D6. [Add back]. The probability that this step is necessary is very
1717 // small, on the order of only 2/b. Make sure that test data accounts for
1718 // this possibility. Decrease q[j] by 1
1720 // and add (0v[n-1]...v[1]v[0]) to (u[j+n]u[j+n-1]...u[j+1]u[j]).
1721 // A carry will occur to the left of u[j+n], and it should be ignored
1722 // since it cancels with the borrow that occurred in D4.
1724 for (unsigned i = 0; i < n; i++) {
1725 unsigned limit = std::min(u[j+i],v[i]);
1726 u[j+i] += v[i] + carry;
1727 carry = u[j+i] < limit || (carry && u[j+i] == limit);
1731 DEBUG(dbgs() << "KnuthDiv: after correction:");
1732 DEBUG(for (int i = m+n; i >=0; i--) dbgs() <<" " << u[i]);
1733 DEBUG(dbgs() << "\nKnuthDiv: digit result = " << q[j] << '\n');
1735 // D7. [Loop on j.] Decrease j by one. Now if j >= 0, go back to D3.
1738 DEBUG(dbgs() << "KnuthDiv: quotient:");
1739 DEBUG(for (int i = m; i >=0; i--) dbgs() <<" " << q[i]);
1740 DEBUG(dbgs() << '\n');
1742 // D8. [Unnormalize]. Now q[...] is the desired quotient, and the desired
1743 // remainder may be obtained by dividing u[...] by d. If r is non-null we
1744 // compute the remainder (urem uses this).
1746 // The value d is expressed by the "shift" value above since we avoided
1747 // multiplication by d by using a shift left. So, all we have to do is
1748 // shift right here. In order to mak
1751 DEBUG(dbgs() << "KnuthDiv: remainder:");
1752 for (int i = n-1; i >= 0; i--) {
1753 r[i] = (u[i] >> shift) | carry;
1754 carry = u[i] << (32 - shift);
1755 DEBUG(dbgs() << " " << r[i]);
1758 for (int i = n-1; i >= 0; i--) {
1760 DEBUG(dbgs() << " " << r[i]);
1763 DEBUG(dbgs() << '\n');
1766 DEBUG(dbgs() << '\n');
1770 void APInt::divide(const APInt LHS, unsigned lhsWords,
1771 const APInt &RHS, unsigned rhsWords,
1772 APInt *Quotient, APInt *Remainder)
1774 assert(lhsWords >= rhsWords && "Fractional result");
1776 // First, compose the values into an array of 32-bit words instead of
1777 // 64-bit words. This is a necessity of both the "short division" algorithm
1778 // and the Knuth "classical algorithm" which requires there to be native
1779 // operations for +, -, and * on an m bit value with an m*2 bit result. We
1780 // can't use 64-bit operands here because we don't have native results of
1781 // 128-bits. Furthermore, casting the 64-bit values to 32-bit values won't
1782 // work on large-endian machines.
1783 uint64_t mask = ~0ull >> (sizeof(unsigned)*CHAR_BIT);
1784 unsigned n = rhsWords * 2;
1785 unsigned m = (lhsWords * 2) - n;
1787 // Allocate space for the temporary values we need either on the stack, if
1788 // it will fit, or on the heap if it won't.
1789 unsigned SPACE[128];
1794 if ((Remainder?4:3)*n+2*m+1 <= 128) {
1797 Q = &SPACE[(m+n+1) + n];
1799 R = &SPACE[(m+n+1) + n + (m+n)];
1801 U = new unsigned[m + n + 1];
1802 V = new unsigned[n];
1803 Q = new unsigned[m+n];
1805 R = new unsigned[n];
1808 // Initialize the dividend
1809 memset(U, 0, (m+n+1)*sizeof(unsigned));
1810 for (unsigned i = 0; i < lhsWords; ++i) {
1811 uint64_t tmp = (LHS.getNumWords() == 1 ? LHS.VAL : LHS.pVal[i]);
1812 U[i * 2] = (unsigned)(tmp & mask);
1813 U[i * 2 + 1] = (unsigned)(tmp >> (sizeof(unsigned)*CHAR_BIT));
1815 U[m+n] = 0; // this extra word is for "spill" in the Knuth algorithm.
1817 // Initialize the divisor
1818 memset(V, 0, (n)*sizeof(unsigned));
1819 for (unsigned i = 0; i < rhsWords; ++i) {
1820 uint64_t tmp = (RHS.getNumWords() == 1 ? RHS.VAL : RHS.pVal[i]);
1821 V[i * 2] = (unsigned)(tmp & mask);
1822 V[i * 2 + 1] = (unsigned)(tmp >> (sizeof(unsigned)*CHAR_BIT));
1825 // initialize the quotient and remainder
1826 memset(Q, 0, (m+n) * sizeof(unsigned));
1828 memset(R, 0, n * sizeof(unsigned));
1830 // Now, adjust m and n for the Knuth division. n is the number of words in
1831 // the divisor. m is the number of words by which the dividend exceeds the
1832 // divisor (i.e. m+n is the length of the dividend). These sizes must not
1833 // contain any zero words or the Knuth algorithm fails.
1834 for (unsigned i = n; i > 0 && V[i-1] == 0; i--) {
1838 for (unsigned i = m+n; i > 0 && U[i-1] == 0; i--)
1841 // If we're left with only a single word for the divisor, Knuth doesn't work
1842 // so we implement the short division algorithm here. This is much simpler
1843 // and faster because we are certain that we can divide a 64-bit quantity
1844 // by a 32-bit quantity at hardware speed and short division is simply a
1845 // series of such operations. This is just like doing short division but we
1846 // are using base 2^32 instead of base 10.
1847 assert(n != 0 && "Divide by zero?");
1849 unsigned divisor = V[0];
1850 unsigned remainder = 0;
1851 for (int i = m+n-1; i >= 0; i--) {
1852 uint64_t partial_dividend = uint64_t(remainder) << 32 | U[i];
1853 if (partial_dividend == 0) {
1856 } else if (partial_dividend < divisor) {
1858 remainder = (unsigned)partial_dividend;
1859 } else if (partial_dividend == divisor) {
1863 Q[i] = (unsigned)(partial_dividend / divisor);
1864 remainder = (unsigned)(partial_dividend - (Q[i] * divisor));
1870 // Now we're ready to invoke the Knuth classical divide algorithm. In this
1872 KnuthDiv(U, V, Q, R, m, n);
1875 // If the caller wants the quotient
1877 // Set up the Quotient value's memory.
1878 if (Quotient->BitWidth != LHS.BitWidth) {
1879 if (Quotient->isSingleWord())
1882 delete [] Quotient->pVal;
1883 Quotient->BitWidth = LHS.BitWidth;
1884 if (!Quotient->isSingleWord())
1885 Quotient->pVal = getClearedMemory(Quotient->getNumWords());
1887 Quotient->clearAllBits();
1889 // The quotient is in Q. Reconstitute the quotient into Quotient's low
1891 if (lhsWords == 1) {
1893 uint64_t(Q[0]) | (uint64_t(Q[1]) << (APINT_BITS_PER_WORD / 2));
1894 if (Quotient->isSingleWord())
1895 Quotient->VAL = tmp;
1897 Quotient->pVal[0] = tmp;
1899 assert(!Quotient->isSingleWord() && "Quotient APInt not large enough");
1900 for (unsigned i = 0; i < lhsWords; ++i)
1902 uint64_t(Q[i*2]) | (uint64_t(Q[i*2+1]) << (APINT_BITS_PER_WORD / 2));
1906 // If the caller wants the remainder
1908 // Set up the Remainder value's memory.
1909 if (Remainder->BitWidth != RHS.BitWidth) {
1910 if (Remainder->isSingleWord())
1913 delete [] Remainder->pVal;
1914 Remainder->BitWidth = RHS.BitWidth;
1915 if (!Remainder->isSingleWord())
1916 Remainder->pVal = getClearedMemory(Remainder->getNumWords());
1918 Remainder->clearAllBits();
1920 // The remainder is in R. Reconstitute the remainder into Remainder's low
1922 if (rhsWords == 1) {
1924 uint64_t(R[0]) | (uint64_t(R[1]) << (APINT_BITS_PER_WORD / 2));
1925 if (Remainder->isSingleWord())
1926 Remainder->VAL = tmp;
1928 Remainder->pVal[0] = tmp;
1930 assert(!Remainder->isSingleWord() && "Remainder APInt not large enough");
1931 for (unsigned i = 0; i < rhsWords; ++i)
1932 Remainder->pVal[i] =
1933 uint64_t(R[i*2]) | (uint64_t(R[i*2+1]) << (APINT_BITS_PER_WORD / 2));
1937 // Clean up the memory we allocated.
1938 if (U != &SPACE[0]) {
1946 APInt APInt::udiv(const APInt& RHS) const {
1947 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
1949 // First, deal with the easy case
1950 if (isSingleWord()) {
1951 assert(RHS.VAL != 0 && "Divide by zero?");
1952 return APInt(BitWidth, VAL / RHS.VAL);
1955 // Get some facts about the LHS and RHS number of bits and words
1956 unsigned rhsBits = RHS.getActiveBits();
1957 unsigned rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1);
1958 assert(rhsWords && "Divided by zero???");
1959 unsigned lhsBits = this->getActiveBits();
1960 unsigned lhsWords = !lhsBits ? 0 : (APInt::whichWord(lhsBits - 1) + 1);
1962 // Deal with some degenerate cases
1965 return APInt(BitWidth, 0);
1966 else if (lhsWords < rhsWords || this->ult(RHS)) {
1967 // X / Y ===> 0, iff X < Y
1968 return APInt(BitWidth, 0);
1969 } else if (*this == RHS) {
1971 return APInt(BitWidth, 1);
1972 } else if (lhsWords == 1 && rhsWords == 1) {
1973 // All high words are zero, just use native divide
1974 return APInt(BitWidth, this->pVal[0] / RHS.pVal[0]);
1977 // We have to compute it the hard way. Invoke the Knuth divide algorithm.
1978 APInt Quotient(1,0); // to hold result.
1979 divide(*this, lhsWords, RHS, rhsWords, &Quotient, 0);
1983 APInt APInt::urem(const APInt& RHS) const {
1984 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
1985 if (isSingleWord()) {
1986 assert(RHS.VAL != 0 && "Remainder by zero?");
1987 return APInt(BitWidth, VAL % RHS.VAL);
1990 // Get some facts about the LHS
1991 unsigned lhsBits = getActiveBits();
1992 unsigned lhsWords = !lhsBits ? 0 : (whichWord(lhsBits - 1) + 1);
1994 // Get some facts about the RHS
1995 unsigned rhsBits = RHS.getActiveBits();
1996 unsigned rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1);
1997 assert(rhsWords && "Performing remainder operation by zero ???");
1999 // Check the degenerate cases
2000 if (lhsWords == 0) {
2002 return APInt(BitWidth, 0);
2003 } else if (lhsWords < rhsWords || this->ult(RHS)) {
2004 // X % Y ===> X, iff X < Y
2006 } else if (*this == RHS) {
2008 return APInt(BitWidth, 0);
2009 } else if (lhsWords == 1) {
2010 // All high words are zero, just use native remainder
2011 return APInt(BitWidth, pVal[0] % RHS.pVal[0]);
2014 // We have to compute it the hard way. Invoke the Knuth divide algorithm.
2015 APInt Remainder(1,0);
2016 divide(*this, lhsWords, RHS, rhsWords, 0, &Remainder);
2020 void APInt::udivrem(const APInt &LHS, const APInt &RHS,
2021 APInt &Quotient, APInt &Remainder) {
2022 // Get some size facts about the dividend and divisor
2023 unsigned lhsBits = LHS.getActiveBits();
2024 unsigned lhsWords = !lhsBits ? 0 : (APInt::whichWord(lhsBits - 1) + 1);
2025 unsigned rhsBits = RHS.getActiveBits();
2026 unsigned rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1);
2028 // Check the degenerate cases
2029 if (lhsWords == 0) {
2030 Quotient = 0; // 0 / Y ===> 0
2031 Remainder = 0; // 0 % Y ===> 0
2035 if (lhsWords < rhsWords || LHS.ult(RHS)) {
2036 Remainder = LHS; // X % Y ===> X, iff X < Y
2037 Quotient = 0; // X / Y ===> 0, iff X < Y
2042 Quotient = 1; // X / X ===> 1
2043 Remainder = 0; // X % X ===> 0;
2047 if (lhsWords == 1 && rhsWords == 1) {
2048 // There is only one word to consider so use the native versions.
2049 uint64_t lhsValue = LHS.isSingleWord() ? LHS.VAL : LHS.pVal[0];
2050 uint64_t rhsValue = RHS.isSingleWord() ? RHS.VAL : RHS.pVal[0];
2051 Quotient = APInt(LHS.getBitWidth(), lhsValue / rhsValue);
2052 Remainder = APInt(LHS.getBitWidth(), lhsValue % rhsValue);
2056 // Okay, lets do it the long way
2057 divide(LHS, lhsWords, RHS, rhsWords, &Quotient, &Remainder);
2060 APInt APInt::sadd_ov(const APInt &RHS, bool &Overflow) const {
2061 APInt Res = *this+RHS;
2062 Overflow = isNonNegative() == RHS.isNonNegative() &&
2063 Res.isNonNegative() != isNonNegative();
2067 APInt APInt::uadd_ov(const APInt &RHS, bool &Overflow) const {
2068 APInt Res = *this+RHS;
2069 Overflow = Res.ult(RHS);
2073 APInt APInt::ssub_ov(const APInt &RHS, bool &Overflow) const {
2074 APInt Res = *this - RHS;
2075 Overflow = isNonNegative() != RHS.isNonNegative() &&
2076 Res.isNonNegative() != isNonNegative();
2080 APInt APInt::usub_ov(const APInt &RHS, bool &Overflow) const {
2081 APInt Res = *this-RHS;
2082 Overflow = Res.ugt(*this);
2086 APInt APInt::sdiv_ov(const APInt &RHS, bool &Overflow) const {
2087 // MININT/-1 --> overflow.
2088 Overflow = isMinSignedValue() && RHS.isAllOnesValue();
2092 APInt APInt::smul_ov(const APInt &RHS, bool &Overflow) const {
2093 APInt Res = *this * RHS;
2095 if (*this != 0 && RHS != 0)
2096 Overflow = Res.sdiv(RHS) != *this || Res.sdiv(*this) != RHS;
2102 APInt APInt::umul_ov(const APInt &RHS, bool &Overflow) const {
2103 APInt Res = *this * RHS;
2105 if (*this != 0 && RHS != 0)
2106 Overflow = Res.udiv(RHS) != *this || Res.udiv(*this) != RHS;
2112 APInt APInt::sshl_ov(unsigned ShAmt, bool &Overflow) const {
2113 Overflow = ShAmt >= getBitWidth();
2115 ShAmt = getBitWidth()-1;
2117 if (isNonNegative()) // Don't allow sign change.
2118 Overflow = ShAmt >= countLeadingZeros();
2120 Overflow = ShAmt >= countLeadingOnes();
2122 return *this << ShAmt;
2128 void APInt::fromString(unsigned numbits, StringRef str, uint8_t radix) {
2129 // Check our assumptions here
2130 assert(!str.empty() && "Invalid string length");
2131 assert((radix == 10 || radix == 8 || radix == 16 || radix == 2 ||
2133 "Radix should be 2, 8, 10, 16, or 36!");
2135 StringRef::iterator p = str.begin();
2136 size_t slen = str.size();
2137 bool isNeg = *p == '-';
2138 if (*p == '-' || *p == '+') {
2141 assert(slen && "String is only a sign, needs a value.");
2143 assert((slen <= numbits || radix != 2) && "Insufficient bit width");
2144 assert(((slen-1)*3 <= numbits || radix != 8) && "Insufficient bit width");
2145 assert(((slen-1)*4 <= numbits || radix != 16) && "Insufficient bit width");
2146 assert((((slen-1)*64)/22 <= numbits || radix != 10) &&
2147 "Insufficient bit width");
2150 if (!isSingleWord())
2151 pVal = getClearedMemory(getNumWords());
2153 // Figure out if we can shift instead of multiply
2154 unsigned shift = (radix == 16 ? 4 : radix == 8 ? 3 : radix == 2 ? 1 : 0);
2156 // Set up an APInt for the digit to add outside the loop so we don't
2157 // constantly construct/destruct it.
2158 APInt apdigit(getBitWidth(), 0);
2159 APInt apradix(getBitWidth(), radix);
2161 // Enter digit traversal loop
2162 for (StringRef::iterator e = str.end(); p != e; ++p) {
2163 unsigned digit = getDigit(*p, radix);
2164 assert(digit < radix && "Invalid character in digit string");
2166 // Shift or multiply the value by the radix
2174 // Add in the digit we just interpreted
2175 if (apdigit.isSingleWord())
2176 apdigit.VAL = digit;
2178 apdigit.pVal[0] = digit;
2181 // If its negative, put it in two's complement form
2184 this->flipAllBits();
2188 void APInt::toString(SmallVectorImpl<char> &Str, unsigned Radix,
2189 bool Signed, bool formatAsCLiteral) const {
2190 assert((Radix == 10 || Radix == 8 || Radix == 16 || Radix == 2 ||
2192 "Radix should be 2, 8, 10, 16, or 36!");
2194 const char *Prefix = "";
2195 if (formatAsCLiteral) {
2198 // Binary literals are a non-standard extension added in gcc 4.3:
2199 // http://gcc.gnu.org/onlinedocs/gcc-4.3.0/gcc/Binary-constants.html
2211 llvm_unreachable("Invalid radix!");
2215 // First, check for a zero value and just short circuit the logic below.
2218 Str.push_back(*Prefix);
2225 static const char Digits[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
2227 if (isSingleWord()) {
2229 char *BufPtr = Buffer+65;
2235 int64_t I = getSExtValue();
2245 Str.push_back(*Prefix);
2250 *--BufPtr = Digits[N % Radix];
2253 Str.append(BufPtr, Buffer+65);
2259 if (Signed && isNegative()) {
2260 // They want to print the signed version and it is a negative value
2261 // Flip the bits and add one to turn it into the equivalent positive
2262 // value and put a '-' in the result.
2269 Str.push_back(*Prefix);
2273 // We insert the digits backward, then reverse them to get the right order.
2274 unsigned StartDig = Str.size();
2276 // For the 2, 8 and 16 bit cases, we can just shift instead of divide
2277 // because the number of bits per digit (1, 3 and 4 respectively) divides
2278 // equaly. We just shift until the value is zero.
2279 if (Radix == 2 || Radix == 8 || Radix == 16) {
2280 // Just shift tmp right for each digit width until it becomes zero
2281 unsigned ShiftAmt = (Radix == 16 ? 4 : (Radix == 8 ? 3 : 1));
2282 unsigned MaskAmt = Radix - 1;
2285 unsigned Digit = unsigned(Tmp.getRawData()[0]) & MaskAmt;
2286 Str.push_back(Digits[Digit]);
2287 Tmp = Tmp.lshr(ShiftAmt);
2290 APInt divisor(Radix == 10? 4 : 8, Radix);
2292 APInt APdigit(1, 0);
2293 APInt tmp2(Tmp.getBitWidth(), 0);
2294 divide(Tmp, Tmp.getNumWords(), divisor, divisor.getNumWords(), &tmp2,
2296 unsigned Digit = (unsigned)APdigit.getZExtValue();
2297 assert(Digit < Radix && "divide failed");
2298 Str.push_back(Digits[Digit]);
2303 // Reverse the digits before returning.
2304 std::reverse(Str.begin()+StartDig, Str.end());
2307 /// toString - This returns the APInt as a std::string. Note that this is an
2308 /// inefficient method. It is better to pass in a SmallVector/SmallString
2309 /// to the methods above.
2310 std::string APInt::toString(unsigned Radix = 10, bool Signed = true) const {
2312 toString(S, Radix, Signed, /* formatAsCLiteral = */false);
2317 void APInt::dump() const {
2318 SmallString<40> S, U;
2319 this->toStringUnsigned(U);
2320 this->toStringSigned(S);
2321 dbgs() << "APInt(" << BitWidth << "b, "
2322 << U.str() << "u " << S.str() << "s)";
2325 void APInt::print(raw_ostream &OS, bool isSigned) const {
2327 this->toString(S, 10, isSigned, /* formatAsCLiteral = */false);
2331 // This implements a variety of operations on a representation of
2332 // arbitrary precision, two's-complement, bignum integer values.
2334 // Assumed by lowHalf, highHalf, partMSB and partLSB. A fairly safe
2335 // and unrestricting assumption.
2336 #define COMPILE_TIME_ASSERT(cond) extern int CTAssert[(cond) ? 1 : -1]
2337 COMPILE_TIME_ASSERT(integerPartWidth % 2 == 0);
2339 /* Some handy functions local to this file. */
2342 /* Returns the integer part with the least significant BITS set.
2343 BITS cannot be zero. */
2344 static inline integerPart
2345 lowBitMask(unsigned int bits)
2347 assert(bits != 0 && bits <= integerPartWidth);
2349 return ~(integerPart) 0 >> (integerPartWidth - bits);
2352 /* Returns the value of the lower half of PART. */
2353 static inline integerPart
2354 lowHalf(integerPart part)
2356 return part & lowBitMask(integerPartWidth / 2);
2359 /* Returns the value of the upper half of PART. */
2360 static inline integerPart
2361 highHalf(integerPart part)
2363 return part >> (integerPartWidth / 2);
2366 /* Returns the bit number of the most significant set bit of a part.
2367 If the input number has no bits set -1U is returned. */
2369 partMSB(integerPart value)
2371 unsigned int n, msb;
2376 n = integerPartWidth / 2;
2391 /* Returns the bit number of the least significant set bit of a
2392 part. If the input number has no bits set -1U is returned. */
2394 partLSB(integerPart value)
2396 unsigned int n, lsb;
2401 lsb = integerPartWidth - 1;
2402 n = integerPartWidth / 2;
2417 /* Sets the least significant part of a bignum to the input value, and
2418 zeroes out higher parts. */
2420 APInt::tcSet(integerPart *dst, integerPart part, unsigned int parts)
2427 for (i = 1; i < parts; i++)
2431 /* Assign one bignum to another. */
2433 APInt::tcAssign(integerPart *dst, const integerPart *src, unsigned int parts)
2437 for (i = 0; i < parts; i++)
2441 /* Returns true if a bignum is zero, false otherwise. */
2443 APInt::tcIsZero(const integerPart *src, unsigned int parts)
2447 for (i = 0; i < parts; i++)
2454 /* Extract the given bit of a bignum; returns 0 or 1. */
2456 APInt::tcExtractBit(const integerPart *parts, unsigned int bit)
2458 return (parts[bit / integerPartWidth] &
2459 ((integerPart) 1 << bit % integerPartWidth)) != 0;
2462 /* Set the given bit of a bignum. */
2464 APInt::tcSetBit(integerPart *parts, unsigned int bit)
2466 parts[bit / integerPartWidth] |= (integerPart) 1 << (bit % integerPartWidth);
2469 /* Clears the given bit of a bignum. */
2471 APInt::tcClearBit(integerPart *parts, unsigned int bit)
2473 parts[bit / integerPartWidth] &=
2474 ~((integerPart) 1 << (bit % integerPartWidth));
2477 /* Returns the bit number of the least significant set bit of a
2478 number. If the input number has no bits set -1U is returned. */
2480 APInt::tcLSB(const integerPart *parts, unsigned int n)
2482 unsigned int i, lsb;
2484 for (i = 0; i < n; i++) {
2485 if (parts[i] != 0) {
2486 lsb = partLSB(parts[i]);
2488 return lsb + i * integerPartWidth;
2495 /* Returns the bit number of the most significant set bit of a number.
2496 If the input number has no bits set -1U is returned. */
2498 APInt::tcMSB(const integerPart *parts, unsigned int n)
2505 if (parts[n] != 0) {
2506 msb = partMSB(parts[n]);
2508 return msb + n * integerPartWidth;
2515 /* Copy the bit vector of width srcBITS from SRC, starting at bit
2516 srcLSB, to DST, of dstCOUNT parts, such that the bit srcLSB becomes
2517 the least significant bit of DST. All high bits above srcBITS in
2518 DST are zero-filled. */
2520 APInt::tcExtract(integerPart *dst, unsigned int dstCount,const integerPart *src,
2521 unsigned int srcBits, unsigned int srcLSB)
2523 unsigned int firstSrcPart, dstParts, shift, n;
2525 dstParts = (srcBits + integerPartWidth - 1) / integerPartWidth;
2526 assert(dstParts <= dstCount);
2528 firstSrcPart = srcLSB / integerPartWidth;
2529 tcAssign (dst, src + firstSrcPart, dstParts);
2531 shift = srcLSB % integerPartWidth;
2532 tcShiftRight (dst, dstParts, shift);
2534 /* We now have (dstParts * integerPartWidth - shift) bits from SRC
2535 in DST. If this is less that srcBits, append the rest, else
2536 clear the high bits. */
2537 n = dstParts * integerPartWidth - shift;
2539 integerPart mask = lowBitMask (srcBits - n);
2540 dst[dstParts - 1] |= ((src[firstSrcPart + dstParts] & mask)
2541 << n % integerPartWidth);
2542 } else if (n > srcBits) {
2543 if (srcBits % integerPartWidth)
2544 dst[dstParts - 1] &= lowBitMask (srcBits % integerPartWidth);
2547 /* Clear high parts. */
2548 while (dstParts < dstCount)
2549 dst[dstParts++] = 0;
2552 /* DST += RHS + C where C is zero or one. Returns the carry flag. */
2554 APInt::tcAdd(integerPart *dst, const integerPart *rhs,
2555 integerPart c, unsigned int parts)
2561 for (i = 0; i < parts; i++) {
2566 dst[i] += rhs[i] + 1;
2577 /* DST -= RHS + C where C is zero or one. Returns the carry flag. */
2579 APInt::tcSubtract(integerPart *dst, const integerPart *rhs,
2580 integerPart c, unsigned int parts)
2586 for (i = 0; i < parts; i++) {
2591 dst[i] -= rhs[i] + 1;
2602 /* Negate a bignum in-place. */
2604 APInt::tcNegate(integerPart *dst, unsigned int parts)
2606 tcComplement(dst, parts);
2607 tcIncrement(dst, parts);
2610 /* DST += SRC * MULTIPLIER + CARRY if add is true
2611 DST = SRC * MULTIPLIER + CARRY if add is false
2613 Requires 0 <= DSTPARTS <= SRCPARTS + 1. If DST overlaps SRC
2614 they must start at the same point, i.e. DST == SRC.
2616 If DSTPARTS == SRCPARTS + 1 no overflow occurs and zero is
2617 returned. Otherwise DST is filled with the least significant
2618 DSTPARTS parts of the result, and if all of the omitted higher
2619 parts were zero return zero, otherwise overflow occurred and
2622 APInt::tcMultiplyPart(integerPart *dst, const integerPart *src,
2623 integerPart multiplier, integerPart carry,
2624 unsigned int srcParts, unsigned int dstParts,
2629 /* Otherwise our writes of DST kill our later reads of SRC. */
2630 assert(dst <= src || dst >= src + srcParts);
2631 assert(dstParts <= srcParts + 1);
2633 /* N loops; minimum of dstParts and srcParts. */
2634 n = dstParts < srcParts ? dstParts: srcParts;
2636 for (i = 0; i < n; i++) {
2637 integerPart low, mid, high, srcPart;
2639 /* [ LOW, HIGH ] = MULTIPLIER * SRC[i] + DST[i] + CARRY.
2641 This cannot overflow, because
2643 (n - 1) * (n - 1) + 2 (n - 1) = (n - 1) * (n + 1)
2645 which is less than n^2. */
2649 if (multiplier == 0 || srcPart == 0) {
2653 low = lowHalf(srcPart) * lowHalf(multiplier);
2654 high = highHalf(srcPart) * highHalf(multiplier);
2656 mid = lowHalf(srcPart) * highHalf(multiplier);
2657 high += highHalf(mid);
2658 mid <<= integerPartWidth / 2;
2659 if (low + mid < low)
2663 mid = highHalf(srcPart) * lowHalf(multiplier);
2664 high += highHalf(mid);
2665 mid <<= integerPartWidth / 2;
2666 if (low + mid < low)
2670 /* Now add carry. */
2671 if (low + carry < low)
2677 /* And now DST[i], and store the new low part there. */
2678 if (low + dst[i] < low)
2688 /* Full multiplication, there is no overflow. */
2689 assert(i + 1 == dstParts);
2693 /* We overflowed if there is carry. */
2697 /* We would overflow if any significant unwritten parts would be
2698 non-zero. This is true if any remaining src parts are non-zero
2699 and the multiplier is non-zero. */
2701 for (; i < srcParts; i++)
2705 /* We fitted in the narrow destination. */
2710 /* DST = LHS * RHS, where DST has the same width as the operands and
2711 is filled with the least significant parts of the result. Returns
2712 one if overflow occurred, otherwise zero. DST must be disjoint
2713 from both operands. */
2715 APInt::tcMultiply(integerPart *dst, const integerPart *lhs,
2716 const integerPart *rhs, unsigned int parts)
2721 assert(dst != lhs && dst != rhs);
2724 tcSet(dst, 0, parts);
2726 for (i = 0; i < parts; i++)
2727 overflow |= tcMultiplyPart(&dst[i], lhs, rhs[i], 0, parts,
2733 /* DST = LHS * RHS, where DST has width the sum of the widths of the
2734 operands. No overflow occurs. DST must be disjoint from both
2735 operands. Returns the number of parts required to hold the
2738 APInt::tcFullMultiply(integerPart *dst, const integerPart *lhs,
2739 const integerPart *rhs, unsigned int lhsParts,
2740 unsigned int rhsParts)
2742 /* Put the narrower number on the LHS for less loops below. */
2743 if (lhsParts > rhsParts) {
2744 return tcFullMultiply (dst, rhs, lhs, rhsParts, lhsParts);
2748 assert(dst != lhs && dst != rhs);
2750 tcSet(dst, 0, rhsParts);
2752 for (n = 0; n < lhsParts; n++)
2753 tcMultiplyPart(&dst[n], rhs, lhs[n], 0, rhsParts, rhsParts + 1, true);
2755 n = lhsParts + rhsParts;
2757 return n - (dst[n - 1] == 0);
2761 /* If RHS is zero LHS and REMAINDER are left unchanged, return one.
2762 Otherwise set LHS to LHS / RHS with the fractional part discarded,
2763 set REMAINDER to the remainder, return zero. i.e.
2765 OLD_LHS = RHS * LHS + REMAINDER
2767 SCRATCH is a bignum of the same size as the operands and result for
2768 use by the routine; its contents need not be initialized and are
2769 destroyed. LHS, REMAINDER and SCRATCH must be distinct.
2772 APInt::tcDivide(integerPart *lhs, const integerPart *rhs,
2773 integerPart *remainder, integerPart *srhs,
2776 unsigned int n, shiftCount;
2779 assert(lhs != remainder && lhs != srhs && remainder != srhs);
2781 shiftCount = tcMSB(rhs, parts) + 1;
2782 if (shiftCount == 0)
2785 shiftCount = parts * integerPartWidth - shiftCount;
2786 n = shiftCount / integerPartWidth;
2787 mask = (integerPart) 1 << (shiftCount % integerPartWidth);
2789 tcAssign(srhs, rhs, parts);
2790 tcShiftLeft(srhs, parts, shiftCount);
2791 tcAssign(remainder, lhs, parts);
2792 tcSet(lhs, 0, parts);
2794 /* Loop, subtracting SRHS if REMAINDER is greater and adding that to
2799 compare = tcCompare(remainder, srhs, parts);
2801 tcSubtract(remainder, srhs, 0, parts);
2805 if (shiftCount == 0)
2808 tcShiftRight(srhs, parts, 1);
2809 if ((mask >>= 1) == 0)
2810 mask = (integerPart) 1 << (integerPartWidth - 1), n--;
2816 /* Shift a bignum left COUNT bits in-place. Shifted in bits are zero.
2817 There are no restrictions on COUNT. */
2819 APInt::tcShiftLeft(integerPart *dst, unsigned int parts, unsigned int count)
2822 unsigned int jump, shift;
2824 /* Jump is the inter-part jump; shift is is intra-part shift. */
2825 jump = count / integerPartWidth;
2826 shift = count % integerPartWidth;
2828 while (parts > jump) {
2833 /* dst[i] comes from the two parts src[i - jump] and, if we have
2834 an intra-part shift, src[i - jump - 1]. */
2835 part = dst[parts - jump];
2838 if (parts >= jump + 1)
2839 part |= dst[parts - jump - 1] >> (integerPartWidth - shift);
2850 /* Shift a bignum right COUNT bits in-place. Shifted in bits are
2851 zero. There are no restrictions on COUNT. */
2853 APInt::tcShiftRight(integerPart *dst, unsigned int parts, unsigned int count)
2856 unsigned int i, jump, shift;
2858 /* Jump is the inter-part jump; shift is is intra-part shift. */
2859 jump = count / integerPartWidth;
2860 shift = count % integerPartWidth;
2862 /* Perform the shift. This leaves the most significant COUNT bits
2863 of the result at zero. */
2864 for (i = 0; i < parts; i++) {
2867 if (i + jump >= parts) {
2870 part = dst[i + jump];
2873 if (i + jump + 1 < parts)
2874 part |= dst[i + jump + 1] << (integerPartWidth - shift);
2883 /* Bitwise and of two bignums. */
2885 APInt::tcAnd(integerPart *dst, const integerPart *rhs, unsigned int parts)
2889 for (i = 0; i < parts; i++)
2893 /* Bitwise inclusive or of two bignums. */
2895 APInt::tcOr(integerPart *dst, const integerPart *rhs, unsigned int parts)
2899 for (i = 0; i < parts; i++)
2903 /* Bitwise exclusive or of two bignums. */
2905 APInt::tcXor(integerPart *dst, const integerPart *rhs, unsigned int parts)
2909 for (i = 0; i < parts; i++)
2913 /* Complement a bignum in-place. */
2915 APInt::tcComplement(integerPart *dst, unsigned int parts)
2919 for (i = 0; i < parts; i++)
2923 /* Comparison (unsigned) of two bignums. */
2925 APInt::tcCompare(const integerPart *lhs, const integerPart *rhs,
2930 if (lhs[parts] == rhs[parts])
2933 if (lhs[parts] > rhs[parts])
2942 /* Increment a bignum in-place, return the carry flag. */
2944 APInt::tcIncrement(integerPart *dst, unsigned int parts)
2948 for (i = 0; i < parts; i++)
2955 /* Set the least significant BITS bits of a bignum, clear the
2958 APInt::tcSetLeastSignificantBits(integerPart *dst, unsigned int parts,
2964 while (bits > integerPartWidth) {
2965 dst[i++] = ~(integerPart) 0;
2966 bits -= integerPartWidth;
2970 dst[i++] = ~(integerPart) 0 >> (integerPartWidth - bits);