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llvm/lib/Support/APInt.cpp
Reid Spencer 9c0696f153 First version that can process arith.cpp test case up to 1024 bits: 
1. Ensure pVal is set to 0 in each constructor.
2. Fix roundToDouble to make correct calculations and not read beyond the
   end of allocated memory.
3. Implement Knuth's "classical algorithm" for division from scratch and
   eliminate buffer overflows and uninitialized mememory reads. Document
   it properly too.
4. Implement a wrapper function for KnuthDiv which handles the 64-bit to
   32-bit conversion and back. It also implement short division for the
   n == 1 case that Knuth's algorithm can't handle.
5. Simplify the logic of udiv and urem a little, make them exit early, and
   have them use the "divide" wrapper function to perform the division
   or remainder operation.
6. Move the toString function to the end of the file, closer to where
   the division functions are located.

Note: division is still broken for some > 64 bit values, but at least it
      doesn't crash any more.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34449 91177308-0d34-0410-b5e6-96231b3b80d8
2007-02-20 08:51:03 +00:00

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//===-- APInt.cpp - Implement APInt class ---------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Sheng Zhou and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a class to represent arbitrary precision integral
// constant values.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/APInt.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Support/MathExtras.h"
#include <cstring>
#include <cstdlib>
using namespace llvm;
// A utility function for allocating memory, checking for allocation failures,
// and ensuring the contents is zeroed.
inline static uint64_t* getClearedMemory(uint32_t numWords) {
uint64_t * result = new uint64_t[numWords];
assert(result && "APInt memory allocation fails!");
memset(result, 0, numWords * sizeof(uint64_t));
return result;
}
// A utility function for allocating memory and checking for allocation failure.
inline static uint64_t* getMemory(uint32_t numWords) {
uint64_t * result = new uint64_t[numWords];
assert(result && "APInt memory allocation fails!");
return result;
}
APInt::APInt(uint32_t numBits, uint64_t val)
: BitWidth(numBits), pVal(0) {
assert(BitWidth >= IntegerType::MIN_INT_BITS && "bitwidth too small");
assert(BitWidth <= IntegerType::MAX_INT_BITS && "bitwidth too large");
if (isSingleWord())
VAL = val & (~uint64_t(0ULL) >> (APINT_BITS_PER_WORD - BitWidth));
else {
pVal = getClearedMemory(getNumWords());
pVal[0] = val;
}
}
APInt::APInt(uint32_t numBits, uint32_t numWords, uint64_t bigVal[])
: BitWidth(numBits), pVal(0) {
assert(BitWidth >= IntegerType::MIN_INT_BITS && "bitwidth too small");
assert(BitWidth <= IntegerType::MAX_INT_BITS && "bitwidth too large");
assert(bigVal && "Null pointer detected!");
if (isSingleWord())
VAL = bigVal[0] & (~uint64_t(0ULL) >> (APINT_BITS_PER_WORD - BitWidth));
else {
pVal = getMemory(getNumWords());
// Calculate the actual length of bigVal[].
uint32_t maxN = std::max<uint32_t>(numWords, getNumWords());
uint32_t minN = std::min<uint32_t>(numWords, getNumWords());
memcpy(pVal, bigVal, (minN - 1) * APINT_WORD_SIZE);
pVal[minN-1] = bigVal[minN-1] &
(~uint64_t(0ULL) >>
(APINT_BITS_PER_WORD - BitWidth % APINT_BITS_PER_WORD));
if (maxN == getNumWords())
memset(pVal+numWords, 0, (getNumWords() - numWords) * APINT_WORD_SIZE);
}
}
/// @brief Create a new APInt by translating the char array represented
/// integer value.
APInt::APInt(uint32_t numbits, const char StrStart[], uint32_t slen,
uint8_t radix)
: BitWidth(numbits), pVal(0) {
fromString(numbits, StrStart, slen, radix);
}
/// @brief Create a new APInt by translating the string represented
/// integer value.
APInt::APInt(uint32_t numbits, const std::string& Val, uint8_t radix)
: BitWidth(numbits), pVal(0) {
assert(!Val.empty() && "String empty?");
fromString(numbits, Val.c_str(), Val.size(), radix);
}
/// @brief Copy constructor
APInt::APInt(const APInt& APIVal)
: BitWidth(APIVal.BitWidth), pVal(0) {
if (isSingleWord())
VAL = APIVal.VAL;
else {
pVal = getMemory(getNumWords());
memcpy(pVal, APIVal.pVal, getNumWords() * APINT_WORD_SIZE);
}
}
APInt::~APInt() {
if (!isSingleWord() && pVal)
delete[] pVal;
}
/// @brief Copy assignment operator. Create a new object from the given
/// APInt one by initialization.
APInt& APInt::operator=(const APInt& RHS) {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord())
VAL = RHS.VAL;
else
memcpy(pVal, RHS.pVal, getNumWords() * APINT_WORD_SIZE);
return *this;
}
/// @brief Assignment operator. Assigns a common case integer value to
/// the APInt.
APInt& APInt::operator=(uint64_t RHS) {
if (isSingleWord())
VAL = RHS;
else {
pVal[0] = RHS;
memset(pVal+1, 0, (getNumWords() - 1) * APINT_WORD_SIZE);
}
return *this;
}
/// add_1 - This function adds a single "digit" integer, y, to the multiple
/// "digit" integer array, x[]. x[] is modified to reflect the addition and
/// 1 is returned if there is a carry out, otherwise 0 is returned.
/// @returns the carry of the addition.
static uint64_t add_1(uint64_t dest[],
uint64_t x[], uint32_t len,
uint64_t y) {
for (uint32_t i = 0; i < len; ++i) {
dest[i] = y + x[i];
if (dest[i] < y)
y = 1;
else {
y = 0;
break;
}
}
return y;
}
/// @brief Prefix increment operator. Increments the APInt by one.
APInt& APInt::operator++() {
if (isSingleWord())
++VAL;
else
add_1(pVal, pVal, getNumWords(), 1);
clearUnusedBits();
return *this;
}
/// sub_1 - This function subtracts a single "digit" (64-bit word), y, from
/// the multi-digit integer array, x[], propagating the borrowed 1 value until
/// no further borrowing is neeeded or it runs out of "digits" in x. The result
/// is 1 if "borrowing" exhausted the digits in x, or 0 if x was not exhausted.
/// In other words, if y > x then this function returns 1, otherwise 0.
static uint64_t sub_1(uint64_t x[], uint32_t len,
uint64_t y) {
for (uint32_t i = 0; i < len; ++i) {
uint64_t X = x[i];
x[i] -= y;
if (y > X)
y = 1; // We have to "borrow 1" from next "digit"
else {
y = 0; // No need to borrow
break; // Remaining digits are unchanged so exit early
}
}
return y;
}
/// @brief Prefix decrement operator. Decrements the APInt by one.
APInt& APInt::operator--() {
if (isSingleWord())
--VAL;
else
sub_1(pVal, getNumWords(), 1);
clearUnusedBits();
return *this;
}
/// add - This function adds the integer array x[] by integer array
/// y[] and returns the carry.
static uint64_t add(uint64_t dest[], uint64_t x[],
uint64_t y[], uint32_t len) {
uint32_t carry = 0;
for (uint32_t i = 0; i< len; ++i) {
carry += x[i];
dest[i] = carry + y[i];
carry = carry < x[i] ? 1 : (dest[i] < carry ? 1 : 0);
}
return carry;
}
/// @brief Addition assignment operator. Adds this APInt by the given APInt&
/// RHS and assigns the result to this APInt.
APInt& APInt::operator+=(const APInt& RHS) {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord()) VAL += RHS.isSingleWord() ? RHS.VAL : RHS.pVal[0];
else {
if (RHS.isSingleWord()) add_1(pVal, pVal, getNumWords(), RHS.VAL);
else {
if (getNumWords() <= RHS.getNumWords())
add(pVal, pVal, RHS.pVal, getNumWords());
else {
uint64_t carry = add(pVal, pVal, RHS.pVal, RHS.getNumWords());
add_1(pVal + RHS.getNumWords(), pVal + RHS.getNumWords(),
getNumWords() - RHS.getNumWords(), carry);
}
}
}
clearUnusedBits();
return *this;
}
/// sub - This function subtracts the integer array x[] by
/// integer array y[], and returns the borrow-out carry.
static uint64_t sub(uint64_t dest[], uint64_t x[],
uint64_t y[], uint32_t len) {
// Carry indicator.
uint64_t cy = 0;
for (uint32_t i = 0; i < len; ++i) {
uint64_t Y = y[i], X = x[i];
Y += cy;
cy = Y < cy ? 1 : 0;
Y = X - Y;
cy += Y > X ? 1 : 0;
dest[i] = Y;
}
return cy;
}
/// @brief Subtraction assignment operator. Subtracts this APInt by the given
/// APInt &RHS and assigns the result to this APInt.
APInt& APInt::operator-=(const APInt& RHS) {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord())
VAL -= RHS.isSingleWord() ? RHS.VAL : RHS.pVal[0];
else {
if (RHS.isSingleWord())
sub_1(pVal, getNumWords(), RHS.VAL);
else {
if (RHS.getNumWords() < getNumWords()) {
uint64_t carry = sub(pVal, pVal, RHS.pVal, RHS.getNumWords());
sub_1(pVal + RHS.getNumWords(), getNumWords() - RHS.getNumWords(),
carry);
}
else
sub(pVal, pVal, RHS.pVal, getNumWords());
}
}
clearUnusedBits();
return *this;
}
/// mul_1 - This function performs the multiplication operation on a
/// large integer (represented as an integer array) and a uint64_t integer.
/// @returns the carry of the multiplication.
static uint64_t mul_1(uint64_t dest[],
uint64_t x[], uint32_t len,
uint64_t y) {
// Split y into high 32-bit part and low 32-bit part.
uint64_t ly = y & 0xffffffffULL, hy = y >> 32;
uint64_t carry = 0, lx, hx;
for (uint32_t i = 0; i < len; ++i) {
lx = x[i] & 0xffffffffULL;
hx = x[i] >> 32;
// hasCarry - A flag to indicate if has carry.
// hasCarry == 0, no carry
// hasCarry == 1, has carry
// hasCarry == 2, no carry and the calculation result == 0.
uint8_t hasCarry = 0;
dest[i] = carry + lx * ly;
// Determine if the add above introduces carry.
hasCarry = (dest[i] < carry) ? 1 : 0;
carry = hx * ly + (dest[i] >> 32) + (hasCarry ? (1ULL << 32) : 0);
// The upper limit of carry can be (2^32 - 1)(2^32 - 1) +
// (2^32 - 1) + 2^32 = 2^64.
hasCarry = (!carry && hasCarry) ? 1 : (!carry ? 2 : 0);
carry += (lx * hy) & 0xffffffffULL;
dest[i] = (carry << 32) | (dest[i] & 0xffffffffULL);
carry = (((!carry && hasCarry != 2) || hasCarry == 1) ? (1ULL << 32) : 0) +
(carry >> 32) + ((lx * hy) >> 32) + hx * hy;
}
return carry;
}
/// mul - This function multiplies integer array x[] by integer array y[] and
/// stores the result into integer array dest[].
/// Note the array dest[]'s size should no less than xlen + ylen.
static void mul(uint64_t dest[], uint64_t x[], uint32_t xlen,
uint64_t y[], uint32_t ylen) {
dest[xlen] = mul_1(dest, x, xlen, y[0]);
for (uint32_t i = 1; i < ylen; ++i) {
uint64_t ly = y[i] & 0xffffffffULL, hy = y[i] >> 32;
uint64_t carry = 0, lx, hx;
for (uint32_t j = 0; j < xlen; ++j) {
lx = x[j] & 0xffffffffULL;
hx = x[j] >> 32;
// hasCarry - A flag to indicate if has carry.
// hasCarry == 0, no carry
// hasCarry == 1, has carry
// hasCarry == 2, no carry and the calculation result == 0.
uint8_t hasCarry = 0;
uint64_t resul = carry + lx * ly;
hasCarry = (resul < carry) ? 1 : 0;
carry = (hasCarry ? (1ULL << 32) : 0) + hx * ly + (resul >> 32);
hasCarry = (!carry && hasCarry) ? 1 : (!carry ? 2 : 0);
carry += (lx * hy) & 0xffffffffULL;
resul = (carry << 32) | (resul & 0xffffffffULL);
dest[i+j] += resul;
carry = (((!carry && hasCarry != 2) || hasCarry == 1) ? (1ULL << 32) : 0)+
(carry >> 32) + (dest[i+j] < resul ? 1 : 0) +
((lx * hy) >> 32) + hx * hy;
}
dest[i+xlen] = carry;
}
}
/// @brief Multiplication assignment operator. Multiplies this APInt by the
/// given APInt& RHS and assigns the result to this APInt.
APInt& APInt::operator*=(const APInt& RHS) {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord()) VAL *= RHS.isSingleWord() ? RHS.VAL : RHS.pVal[0];
else {
// one-based first non-zero bit position.
uint32_t first = getActiveBits();
uint32_t xlen = !first ? 0 : whichWord(first - 1) + 1;
if (!xlen)
return *this;
else if (RHS.isSingleWord())
mul_1(pVal, pVal, xlen, RHS.VAL);
else {
first = RHS.getActiveBits();
uint32_t ylen = !first ? 0 : whichWord(first - 1) + 1;
if (!ylen) {
memset(pVal, 0, getNumWords() * APINT_WORD_SIZE);
return *this;
}
uint64_t *dest = getMemory(xlen+ylen);
mul(dest, pVal, xlen, RHS.pVal, ylen);
memcpy(pVal, dest, ((xlen + ylen >= getNumWords()) ?
getNumWords() : xlen + ylen) * APINT_WORD_SIZE);
delete[] dest;
}
}
clearUnusedBits();
return *this;
}
/// @brief Bitwise AND assignment operator. Performs bitwise AND operation on
/// this APInt and the given APInt& RHS, assigns the result to this APInt.
APInt& APInt::operator&=(const APInt& RHS) {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord()) {
VAL &= RHS.VAL;
return *this;
}
uint32_t numWords = getNumWords();
for (uint32_t i = 0; i < numWords; ++i)
pVal[i] &= RHS.pVal[i];
return *this;
}
/// @brief Bitwise OR assignment operator. Performs bitwise OR operation on
/// this APInt and the given APInt& RHS, assigns the result to this APInt.
APInt& APInt::operator|=(const APInt& RHS) {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord()) {
VAL |= RHS.VAL;
return *this;
}
uint32_t numWords = getNumWords();
for (uint32_t i = 0; i < numWords; ++i)
pVal[i] |= RHS.pVal[i];
return *this;
}
/// @brief Bitwise XOR assignment operator. Performs bitwise XOR operation on
/// this APInt and the given APInt& RHS, assigns the result to this APInt.
APInt& APInt::operator^=(const APInt& RHS) {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord()) {
VAL ^= RHS.VAL;
return *this;
}
uint32_t numWords = getNumWords();
for (uint32_t i = 0; i < numWords; ++i)
pVal[i] ^= RHS.pVal[i];
return *this;
}
/// @brief Bitwise AND operator. Performs bitwise AND operation on this APInt
/// and the given APInt& RHS.
APInt APInt::operator&(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord())
return APInt(getBitWidth(), VAL & RHS.VAL);
APInt Result(*this);
uint32_t numWords = getNumWords();
for (uint32_t i = 0; i < numWords; ++i)
Result.pVal[i] &= RHS.pVal[i];
return Result;
}
/// @brief Bitwise OR operator. Performs bitwise OR operation on this APInt
/// and the given APInt& RHS.
APInt APInt::operator|(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord())
return APInt(getBitWidth(), VAL | RHS.VAL);
APInt Result(*this);
uint32_t numWords = getNumWords();
for (uint32_t i = 0; i < numWords; ++i)
Result.pVal[i] |= RHS.pVal[i];
return Result;
}
/// @brief Bitwise XOR operator. Performs bitwise XOR operation on this APInt
/// and the given APInt& RHS.
APInt APInt::operator^(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord())
return APInt(getBitWidth(), VAL ^ RHS.VAL);
APInt Result(*this);
uint32_t numWords = getNumWords();
for (uint32_t i = 0; i < numWords; ++i)
Result.pVal[i] ^= RHS.pVal[i];
return Result;
}
/// @brief Logical negation operator. Performs logical negation operation on
/// this APInt.
bool APInt::operator !() const {
if (isSingleWord())
return !VAL;
for (uint32_t i = 0; i < getNumWords(); ++i)
if (pVal[i])
return false;
return true;
}
/// @brief Multiplication operator. Multiplies this APInt by the given APInt&
/// RHS.
APInt APInt::operator*(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
APInt API(RHS);
API *= *this;
API.clearUnusedBits();
return API;
}
/// @brief Addition operator. Adds this APInt by the given APInt& RHS.
APInt APInt::operator+(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
APInt API(*this);
API += RHS;
API.clearUnusedBits();
return API;
}
/// @brief Subtraction operator. Subtracts this APInt by the given APInt& RHS
APInt APInt::operator-(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
APInt API(*this);
API -= RHS;
return API;
}
/// @brief Array-indexing support.
bool APInt::operator[](uint32_t bitPosition) const {
return (maskBit(bitPosition) & (isSingleWord() ?
VAL : pVal[whichWord(bitPosition)])) != 0;
}
/// @brief Equality operator. Compare this APInt with the given APInt& RHS
/// for the validity of the equality relationship.
bool APInt::operator==(const APInt& RHS) const {
uint32_t n1 = getActiveBits();
uint32_t n2 = RHS.getActiveBits();
if (n1 != n2) return false;
else if (isSingleWord())
return VAL == (RHS.isSingleWord() ? RHS.VAL : RHS.pVal[0]);
else {
if (n1 <= APINT_BITS_PER_WORD)
return pVal[0] == (RHS.isSingleWord() ? RHS.VAL : RHS.pVal[0]);
for (int i = whichWord(n1 - 1); i >= 0; --i)
if (pVal[i] != RHS.pVal[i]) return false;
}
return true;
}
/// @brief Equality operator. Compare this APInt with the given uint64_t value
/// for the validity of the equality relationship.
bool APInt::operator==(uint64_t Val) const {
if (isSingleWord())
return VAL == Val;
else {
uint32_t n = getActiveBits();
if (n <= APINT_BITS_PER_WORD)
return pVal[0] == Val;
else
return false;
}
}
/// @brief Unsigned less than comparison
bool APInt::ult(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be same for comparison");
if (isSingleWord())
return VAL < RHS.VAL;
else {
uint32_t n1 = getActiveBits();
uint32_t n2 = RHS.getActiveBits();
if (n1 < n2)
return true;
else if (n2 < n1)
return false;
else if (n1 <= APINT_BITS_PER_WORD && n2 <= APINT_BITS_PER_WORD)
return pVal[0] < RHS.pVal[0];
for (int i = whichWord(n1 - 1); i >= 0; --i) {
if (pVal[i] > RHS.pVal[i]) return false;
else if (pVal[i] < RHS.pVal[i]) return true;
}
}
return false;
}
/// @brief Signed less than comparison
bool APInt::slt(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be same for comparison");
if (isSingleWord()) {
int64_t lhsSext = (int64_t(VAL) << (64-BitWidth)) >> (64-BitWidth);
int64_t rhsSext = (int64_t(RHS.VAL) << (64-BitWidth)) >> (64-BitWidth);
return lhsSext < rhsSext;
}
APInt lhs(*this);
APInt rhs(*this);
bool lhsNegative = false;
bool rhsNegative = false;
if (lhs[BitWidth-1]) {
lhsNegative = true;
lhs.flip();
lhs++;
}
if (rhs[BitWidth-1]) {
rhsNegative = true;
rhs.flip();
rhs++;
}
if (lhsNegative)
if (rhsNegative)
return !lhs.ult(rhs);
else
return true;
else if (rhsNegative)
return false;
else
return lhs.ult(rhs);
}
/// Set the given bit to 1 whose poition is given as "bitPosition".
/// @brief Set a given bit to 1.
APInt& APInt::set(uint32_t bitPosition) {
if (isSingleWord()) VAL |= maskBit(bitPosition);
else pVal[whichWord(bitPosition)] |= maskBit(bitPosition);
return *this;
}
/// @brief Set every bit to 1.
APInt& APInt::set() {
if (isSingleWord())
VAL = ~0ULL >> (APINT_BITS_PER_WORD - BitWidth);
else {
for (uint32_t i = 0; i < getNumWords() - 1; ++i)
pVal[i] = -1ULL;
pVal[getNumWords() - 1] = ~0ULL >>
(APINT_BITS_PER_WORD - BitWidth % APINT_BITS_PER_WORD);
}
return *this;
}
/// Set the given bit to 0 whose position is given as "bitPosition".
/// @brief Set a given bit to 0.
APInt& APInt::clear(uint32_t bitPosition) {
if (isSingleWord())
VAL &= ~maskBit(bitPosition);
else
pVal[whichWord(bitPosition)] &= ~maskBit(bitPosition);
return *this;
}
/// @brief Set every bit to 0.
APInt& APInt::clear() {
if (isSingleWord())
VAL = 0;
else
memset(pVal, 0, getNumWords() * APINT_WORD_SIZE);
return *this;
}
/// @brief Bitwise NOT operator. Performs a bitwise logical NOT operation on
/// this APInt.
APInt APInt::operator~() const {
APInt API(*this);
API.flip();
return API;
}
/// @brief Toggle every bit to its opposite value.
APInt& APInt::flip() {
if (isSingleWord()) VAL = (~(VAL <<
(APINT_BITS_PER_WORD - BitWidth))) >> (APINT_BITS_PER_WORD - BitWidth);
else {
uint32_t i = 0;
for (; i < getNumWords() - 1; ++i)
pVal[i] = ~pVal[i];
uint32_t offset =
APINT_BITS_PER_WORD - (BitWidth - APINT_BITS_PER_WORD * (i - 1));
pVal[i] = (~(pVal[i] << offset)) >> offset;
}
return *this;
}
/// Toggle a given bit to its opposite value whose position is given
/// as "bitPosition".
/// @brief Toggles a given bit to its opposite value.
APInt& APInt::flip(uint32_t bitPosition) {
assert(bitPosition < BitWidth && "Out of the bit-width range!");
if ((*this)[bitPosition]) clear(bitPosition);
else set(bitPosition);
return *this;
}
/// getMaxValue - This function returns the largest value
/// for an APInt of the specified bit-width and if isSign == true,
/// it should be largest signed value, otherwise unsigned value.
APInt APInt::getMaxValue(uint32_t numBits, bool isSign) {
APInt Result(numBits, 0);
Result.set();
if (isSign)
Result.clear(numBits - 1);
return Result;
}
/// getMinValue - This function returns the smallest value for
/// an APInt of the given bit-width and if isSign == true,
/// it should be smallest signed value, otherwise zero.
APInt APInt::getMinValue(uint32_t numBits, bool isSign) {
APInt Result(numBits, 0);
if (isSign)
Result.set(numBits - 1);
return Result;
}
/// getAllOnesValue - This function returns an all-ones value for
/// an APInt of the specified bit-width.
APInt APInt::getAllOnesValue(uint32_t numBits) {
return getMaxValue(numBits, false);
}
/// getNullValue - This function creates an '0' value for an
/// APInt of the specified bit-width.
APInt APInt::getNullValue(uint32_t numBits) {
return getMinValue(numBits, false);
}
/// HiBits - This function returns the high "numBits" bits of this APInt.
APInt APInt::getHiBits(uint32_t numBits) const {
return APIntOps::lshr(*this, BitWidth - numBits);
}
/// LoBits - This function returns the low "numBits" bits of this APInt.
APInt APInt::getLoBits(uint32_t numBits) const {
return APIntOps::lshr(APIntOps::shl(*this, BitWidth - numBits),
BitWidth - numBits);
}
bool APInt::isPowerOf2() const {
return (!!*this) && !(*this & (*this - APInt(BitWidth,1)));
}
/// countLeadingZeros - This function is a APInt version corresponding to
/// llvm/include/llvm/Support/MathExtras.h's function
/// countLeadingZeros_{32, 64}. It performs platform optimal form of counting
/// the number of zeros from the most significant bit to the first one bit.
/// @returns numWord() * 64 if the value is zero.
uint32_t APInt::countLeadingZeros() const {
if (isSingleWord())
return CountLeadingZeros_64(VAL) - (APINT_BITS_PER_WORD - BitWidth);
uint32_t Count = 0;
for (uint32_t i = getNumWords(); i > 0u; --i) {
uint32_t tmp = CountLeadingZeros_64(pVal[i-1]);
Count += tmp;
if (tmp != APINT_BITS_PER_WORD)
if (i == getNumWords())
Count -= (APINT_BITS_PER_WORD - whichBit(BitWidth));
break;
}
return Count;
}
/// countTrailingZeros - This function is a APInt version corresponding to
/// llvm/include/llvm/Support/MathExtras.h's function
/// countTrailingZeros_{32, 64}. It performs platform optimal form of counting
/// the number of zeros from the least significant bit to the first one bit.
/// @returns numWord() * 64 if the value is zero.
uint32_t APInt::countTrailingZeros() const {
if (isSingleWord())
return CountTrailingZeros_64(VAL);
APInt Tmp( ~(*this) & ((*this) - APInt(BitWidth,1)) );
return getNumWords() * APINT_BITS_PER_WORD - Tmp.countLeadingZeros();
}
/// countPopulation - This function is a APInt version corresponding to
/// llvm/include/llvm/Support/MathExtras.h's function
/// countPopulation_{32, 64}. It counts the number of set bits in a value.
/// @returns 0 if the value is zero.
uint32_t APInt::countPopulation() const {
if (isSingleWord())
return CountPopulation_64(VAL);
uint32_t Count = 0;
for (uint32_t i = 0; i < getNumWords(); ++i)
Count += CountPopulation_64(pVal[i]);
return Count;
}
/// byteSwap - This function returns a byte-swapped representation of the
/// this APInt.
APInt APInt::byteSwap() const {
assert(BitWidth >= 16 && BitWidth % 16 == 0 && "Cannot byteswap!");
if (BitWidth == 16)
return APInt(BitWidth, ByteSwap_16(VAL));
else if (BitWidth == 32)
return APInt(BitWidth, ByteSwap_32(VAL));
else if (BitWidth == 48) {
uint64_t Tmp1 = ((VAL >> 32) << 16) | (VAL & 0xFFFF);
Tmp1 = ByteSwap_32(Tmp1);
uint64_t Tmp2 = (VAL >> 16) & 0xFFFF;
Tmp2 = ByteSwap_16(Tmp2);
return
APInt(BitWidth,
(Tmp1 & 0xff) | ((Tmp1<<16) & 0xffff00000000ULL) | (Tmp2 << 16));
} else if (BitWidth == 64)
return APInt(BitWidth, ByteSwap_64(VAL));
else {
APInt Result(BitWidth, 0);
char *pByte = (char*)Result.pVal;
for (uint32_t i = 0; i < BitWidth / APINT_WORD_SIZE / 2; ++i) {
char Tmp = pByte[i];
pByte[i] = pByte[BitWidth / APINT_WORD_SIZE - 1 - i];
pByte[BitWidth / APINT_WORD_SIZE - i - 1] = Tmp;
}
return Result;
}
}
/// GreatestCommonDivisor - This function returns the greatest common
/// divisor of the two APInt values using Enclid's algorithm.
APInt llvm::APIntOps::GreatestCommonDivisor(const APInt& API1,
const APInt& API2) {
APInt A = API1, B = API2;
while (!!B) {
APInt T = B;
B = APIntOps::urem(A, B);
A = T;
}
return A;
}
/// DoubleRoundToAPInt - This function convert a double value to
/// a APInt value.
APInt llvm::APIntOps::RoundDoubleToAPInt(double Double) {
union {
double D;
uint64_t I;
} T;
T.D = Double;
bool isNeg = T.I >> 63;
int64_t exp = ((T.I >> 52) & 0x7ff) - 1023;
if (exp < 0)
return APInt(64ull, 0u);
uint64_t mantissa = ((T.I << 12) >> 12) | (1ULL << 52);
if (exp < 52)
return isNeg ? -APInt(64u, mantissa >> (52 - exp)) :
APInt(64u, mantissa >> (52 - exp));
APInt Tmp(exp + 1, mantissa);
Tmp = Tmp.shl(exp - 52);
return isNeg ? -Tmp : Tmp;
}
/// RoundToDouble - This function convert this APInt to a double.
/// The layout for double is as following (IEEE Standard 754):
/// --------------------------------------
/// | Sign Exponent Fraction Bias |
/// |-------------------------------------- |
/// | 1[63] 11[62-52] 52[51-00] 1023 |
/// --------------------------------------
double APInt::roundToDouble(bool isSigned) const {
// Handle the simple case where the value is contained in one uint64_t.
if (isSingleWord() || getActiveBits() <= APINT_BITS_PER_WORD) {
if (isSigned) {
int64_t sext = (int64_t(VAL) << (64-BitWidth)) >> (64-BitWidth);
return double(sext);
} else
return double(VAL);
}
// Determine if the value is negative.
bool isNeg = isSigned ? (*this)[BitWidth-1] : false;
// Construct the absolute value if we're negative.
APInt Tmp(isNeg ? -(*this) : (*this));
// Figure out how many bits we're using.
uint32_t n = Tmp.getActiveBits();
// The exponent (without bias normalization) is just the number of bits
// we are using. Note that the sign bit is gone since we constructed the
// absolute value.
uint64_t exp = n;
// Return infinity for exponent overflow
if (exp > 1023) {
if (!isSigned || !isNeg)
return double(0x0.0p2047L); // positive infinity
else
return double(-0x0.0p2047L); // negative infinity
}
exp += 1023; // Increment for 1023 bias
// Number of bits in mantissa is 52. To obtain the mantissa value, we must
// extract the high 52 bits from the correct words in pVal.
uint64_t mantissa;
unsigned hiWord = whichWord(n-1);
if (hiWord == 0) {
mantissa = Tmp.pVal[0];
if (n > 52)
mantissa >>= n - 52; // shift down, we want the top 52 bits.
} else {
assert(hiWord > 0 && "huh?");
uint64_t hibits = Tmp.pVal[hiWord] << (52 - n % APINT_BITS_PER_WORD);
uint64_t lobits = Tmp.pVal[hiWord-1] >> (11 + n % APINT_BITS_PER_WORD);
mantissa = hibits | lobits;
}
// The leading bit of mantissa is implicit, so get rid of it.
uint64_t sign = isNeg ? (1ULL << (APINT_BITS_PER_WORD - 1)) : 0;
union {
double D;
uint64_t I;
} T;
T.I = sign | (exp << 52) | mantissa;
return T.D;
}
// Truncate to new width.
void APInt::trunc(uint32_t width) {
assert(width < BitWidth && "Invalid APInt Truncate request");
}
// Sign extend to a new width.
void APInt::sext(uint32_t width) {
assert(width > BitWidth && "Invalid APInt SignExtend request");
}
// Zero extend to a new width.
void APInt::zext(uint32_t width) {
assert(width > BitWidth && "Invalid APInt ZeroExtend request");
}
/// Arithmetic right-shift this APInt by shiftAmt.
/// @brief Arithmetic right-shift function.
APInt APInt::ashr(uint32_t shiftAmt) const {
APInt API(*this);
if (API.isSingleWord())
API.VAL =
(((int64_t(API.VAL) << (APINT_BITS_PER_WORD - API.BitWidth)) >>
(APINT_BITS_PER_WORD - API.BitWidth)) >> shiftAmt) &
(~uint64_t(0UL) >> (APINT_BITS_PER_WORD - API.BitWidth));
else {
if (shiftAmt >= API.BitWidth) {
memset(API.pVal, API[API.BitWidth-1] ? 1 : 0,
(API.getNumWords()-1) * APINT_WORD_SIZE);
API.pVal[API.getNumWords() - 1] =
~uint64_t(0UL) >>
(APINT_BITS_PER_WORD - API.BitWidth % APINT_BITS_PER_WORD);
} else {
uint32_t i = 0;
for (; i < API.BitWidth - shiftAmt; ++i)
if (API[i+shiftAmt])
API.set(i);
else
API.clear(i);
for (; i < API.BitWidth; ++i)
if (API[API.BitWidth-1])
API.set(i);
else API.clear(i);
}
}
return API;
}
/// Logical right-shift this APInt by shiftAmt.
/// @brief Logical right-shift function.
APInt APInt::lshr(uint32_t shiftAmt) const {
APInt API(*this);
if (API.isSingleWord())
API.VAL >>= shiftAmt;
else {
if (shiftAmt >= API.BitWidth)
memset(API.pVal, 0, API.getNumWords() * APINT_WORD_SIZE);
uint32_t i = 0;
for (i = 0; i < API.BitWidth - shiftAmt; ++i)
if (API[i+shiftAmt]) API.set(i);
else API.clear(i);
for (; i < API.BitWidth; ++i)
API.clear(i);
}
return API;
}
/// Left-shift this APInt by shiftAmt.
/// @brief Left-shift function.
APInt APInt::shl(uint32_t shiftAmt) const {
APInt API(*this);
if (API.isSingleWord())
API.VAL <<= shiftAmt;
else if (shiftAmt >= API.BitWidth)
memset(API.pVal, 0, API.getNumWords() * APINT_WORD_SIZE);
else {
if (uint32_t offset = shiftAmt / APINT_BITS_PER_WORD) {
for (uint32_t i = API.getNumWords() - 1; i > offset - 1; --i)
API.pVal[i] = API.pVal[i-offset];
memset(API.pVal, 0, offset * APINT_WORD_SIZE);
}
shiftAmt %= APINT_BITS_PER_WORD;
uint32_t i;
for (i = API.getNumWords() - 1; i > 0; --i)
API.pVal[i] = (API.pVal[i] << shiftAmt) |
(API.pVal[i-1] >> (APINT_BITS_PER_WORD - shiftAmt));
API.pVal[i] <<= shiftAmt;
}
API.clearUnusedBits();
return API;
}
#if 0
/// subMul - This function substracts x[len-1:0] * y from
/// dest[offset+len-1:offset], and returns the most significant
/// word of the product, minus the borrow-out from the subtraction.
static uint32_t subMul(uint32_t dest[], uint32_t offset,
uint32_t x[], uint32_t len, uint32_t y) {
uint64_t yl = (uint64_t) y & 0xffffffffL;
uint32_t carry = 0;
uint32_t j = 0;
do {
uint64_t prod = ((uint64_t) x[j] & 0xffffffffUL) * yl;
uint32_t prod_low = (uint32_t) prod;
uint32_t prod_high = (uint32_t) (prod >> 32);
prod_low += carry;
carry = (prod_low < carry ? 1 : 0) + prod_high;
uint32_t x_j = dest[offset+j];
prod_low = x_j - prod_low;
if (prod_low > x_j) ++carry;
dest[offset+j] = prod_low;
} while (++j < len);
return carry;
}
/// unitDiv - This function divides N by D,
/// and returns (remainder << 32) | quotient.
/// Assumes (N >> 32) < D.
static uint64_t unitDiv(uint64_t N, uint32_t D) {
uint64_t q, r; // q: quotient, r: remainder.
uint64_t a1 = N >> 32; // a1: high 32-bit part of N.
uint64_t a0 = N & 0xffffffffL; // a0: low 32-bit part of N
if (a1 < ((D - a1 - (a0 >> 31)) & 0xffffffffL)) {
q = N / D;
r = N % D;
}
else {
// Compute c1*2^32 + c0 = a1*2^32 + a0 - 2^31*d
uint64_t c = N - ((uint64_t) D << 31);
// Divide (c1*2^32 + c0) by d
q = c / D;
r = c % D;
// Add 2^31 to quotient
q += 1 << 31;
}
return (r << 32) | (q & 0xFFFFFFFFl);
}
#endif
/// div - This is basically Knuth's formulation of the classical algorithm.
/// Correspondance with Knuth's notation:
/// Knuth's u[0:m+n] == zds[nx:0].
/// Knuth's v[1:n] == y[ny-1:0]
/// Knuth's n == ny.
/// Knuth's m == nx-ny.
/// Our nx == Knuth's m+n.
/// Could be re-implemented using gmp's mpn_divrem:
/// zds[nx] = mpn_divrem (&zds[ny], 0, zds, nx, y, ny).
/// Implementation of Knuth's Algorithm D (Division of nonnegative integers)
/// from "Art of Computer Programming, Volume 2", section 4.3.1, p. 272. The
/// variables here have the same names as in the algorithm. Comments explain
/// the algorithm and any deviation from it.
static void KnuthDiv(uint32_t *u, uint32_t *v, uint32_t *q, uint32_t* r,
uint32_t m, uint32_t n) {
assert(u && "Must provide dividend");
assert(v && "Must provide divisor");
assert(q && "Must provide quotient");
assert(n>1 && "n must be > 1");
// Knuth uses the value b as the base of the number system. In our case b
// is 2^31 so we just set it to -1u.
uint64_t b = uint64_t(1) << 32;
// D1. [Normalize.] Set d = b / (v[n-1] + 1) and multiply all the digits of
// u and v by d. Note that we have taken Knuth's advice here to use a power
// of 2 value for d such that d * v[n-1] >= b/2 (b is the base). A power of
// 2 allows us to shift instead of multiply and it is easy to determine the
// shift amount from the leading zeros. We are basically normalizing the u
// and v so that its high bits are shifted to the top of v's range without
// overflow. Note that this can require an extra word in u so that u must
// be of length m+n+1.
uint32_t shift = CountLeadingZeros_32(v[n-1]);
uint32_t v_carry = 0;
uint32_t u_carry = 0;
if (shift) {
for (uint32_t i = 0; i < m+n; ++i) {
uint32_t u_tmp = u[i] >> (32 - shift);
u[i] = (u[i] << shift) | u_carry;
u_carry = u_tmp;
}
for (uint32_t i = 0; i < n; ++i) {
uint32_t v_tmp = v[i] >> (32 - shift);
v[i] = (v[i] << shift) | v_carry;
v_carry = v_tmp;
}
}
u[m+n] = u_carry;
// D2. [Initialize j.] Set j to m. This is the loop counter over the places.
int j = m;
do {
// D3. [Calculate q'.].
// Set qp = (u[j+n]*b + u[j+n-1]) / v[n-1]. (qp=qprime=q')
// Set rp = (u[j+n]*b + u[j+n-1]) % v[n-1]. (rp=rprime=r')
// Now test if qp == b or qp*v[n-2] > b*rp + u[j+n-2]; if so, decrease
// qp by 1, inrease rp by v[n-1], and repeat this test if rp < b. The test
// on v[n-2] determines at high speed most of the cases in which the trial
// value qp is one too large, and it eliminates all cases where qp is two
// too large.
uint64_t qp = ((uint64_t(u[j+n]) << 32) | uint64_t(u[j+n-1])) / v[n-1];
uint64_t rp = ((uint64_t(u[j+n]) << 32) | uint64_t(u[j+n-1])) % v[n-1];
if (qp == b || qp*v[n-2] > b*rp + u[j+n-2]) {
qp--;
rp += v[n-1];
}
if (rp < b)
if (qp == b || qp*v[n-2] > b*rp + u[j+n-2]) {
qp--;
rp += v[n-1];
}
// D4. [Multiply and subtract.] Replace u with u - q*v (for each word).
uint32_t borrow = 0;
for (uint32_t i = 0; i < n; i++) {
uint32_t save = u[j+i];
u[j+i] = uint64_t(u[j+i]) - (qp * v[i]) - borrow;
if (u[j+i] > save) {
borrow = 1;
u[j+i+1] += b;
} else {
borrow = 0;
}
}
if (borrow)
u[j+n] += 1;
// D5. [Test remainder.] Set q[j] = qp. If the result of step D4 was
// negative, go to step D6; otherwise go on to step D7.
q[j] = qp;
if (borrow) {
// D6. [Add back]. The probability that this step is necessary is very
// small, on the order of only 2/b. Make sure that test data accounts for
// this possibility. Decreate qj by 1 and add v[...] to u[...]. A carry
// will occur to the left of u[j+n], and it should be ignored since it
// cancels with the borrow that occurred in D4.
uint32_t carry = 0;
for (uint32_t i = 0; i < n; i++) {
uint32_t save = u[j+i];
u[j+i] += v[i] + carry;
carry = u[j+i] < save;
}
}
// D7. [Loop on j.] Decreate j by one. Now if j >= 0, go back to D3.
j--;
} while (j >= 0);
// D8. [Unnormalize]. Now q[...] is the desired quotient, and the desired
// remainder may be obtained by dividing u[...] by d. If r is non-null we
// compute the remainder (urem uses this).
if (r) {
// The value d is expressed by the "shift" value above since we avoided
// multiplication by d by using a shift left. So, all we have to do is
// shift right here. In order to mak
uint32_t mask = ~0u >> (32 - shift);
uint32_t carry = 0;
for (int i = n-1; i >= 0; i--) {
uint32_t save = u[i] & mask;
r[i] = (u[i] >> shift) | carry;
carry = save;
}
}
}
// This function makes calling KnuthDiv a little more convenient. It uses
// APInt parameters instead of uint32_t* parameters. It can also divide APInt
// values of different widths.
void APInt::divide(const APInt LHS, uint32_t lhsWords,
const APInt &RHS, uint32_t rhsWords,
APInt *Quotient, APInt *Remainder)
{
assert(lhsWords >= rhsWords && "Fractional result");
// First, compose the values into an array of 32-bit words instead of
// 64-bit words. This is a necessity of both the "short division" algorithm
// and the the Knuth "classical algorithm" which requires there to be native
// operations for +, -, and * on an m bit value with an m*2 bit result. We
// can't use 64-bit operands here because we don't have native results of
// 128-bits. Furthremore, casting the 64-bit values to 32-bit values won't
// work on large-endian machines.
uint64_t mask = ~0ull >> (sizeof(uint32_t)*8);
uint32_t n = rhsWords * 2;
uint32_t m = (lhsWords * 2) - n;
// FIXME: allocate space on stack if m and n are sufficiently small.
uint32_t *U = new uint32_t[m + n + 1];
memset(U, 0, (m+n+1)*sizeof(uint32_t));
for (unsigned i = 0; i < lhsWords; ++i) {
uint64_t tmp = (lhsWords == 1 ? LHS.VAL : LHS.pVal[i]);
U[i * 2] = tmp & mask;
U[i * 2 + 1] = tmp >> (sizeof(uint32_t)*8);
}
U[m+n] = 0; // this extra word is for "spill" in the Knuth algorithm.
uint32_t *V = new uint32_t[n];
memset(V, 0, (n)*sizeof(uint32_t));
for (unsigned i = 0; i < rhsWords; ++i) {
uint64_t tmp = (rhsWords == 1 ? RHS.VAL : RHS.pVal[i]);
V[i * 2] = tmp & mask;
V[i * 2 + 1] = tmp >> (sizeof(uint32_t)*8);
}
// Set up the quotient and remainder
uint32_t *Q = new uint32_t[m+n];
memset(Q, 0, (m+n) * sizeof(uint32_t));
uint32_t *R = 0;
if (Remainder) {
R = new uint32_t[n];
memset(R, 0, n * sizeof(uint32_t));
}
// Now, adjust m and n for the Knuth division. n is the number of words in
// the divisor. m is the number of words by which the dividend exceeds the
// divisor (i.e. m+n is the length of the dividend). These sizes must not
// contain any zero words or the Knuth algorithm fails.
for (unsigned i = n; i > 0 && V[i-1] == 0; i--) {
n--;
m++;
}
for (unsigned i = m+n; i > 0 && U[i-1] == 0; i--)
m--;
// If we're left with only a single word for the divisor, Knuth doesn't work
// so we implement the short division algorithm here. This is much simpler
// and faster because we are certain that we can divide a 64-bit quantity
// by a 32-bit quantity at hardware speed and short division is simply a
// series of such operations. This is just like doing short division but we
// are using base 2^32 instead of base 10.
assert(n != 0 && "Divide by zero?");
if (n == 1) {
uint32_t divisor = V[0];
uint32_t remainder = 0;
for (int i = m+n-1; i >= 0; i--) {
uint64_t partial_dividend = uint64_t(remainder) << 32 | U[i];
if (partial_dividend == 0) {
Q[i] = 0;
remainder = 0;
} else if (partial_dividend < divisor) {
Q[i] = 0;
remainder = partial_dividend;
} else if (partial_dividend == divisor) {
Q[i] = 1;
remainder = 0;
} else {
Q[i] = partial_dividend / divisor;
remainder = partial_dividend - (Q[i] * divisor);
}
}
if (R)
R[0] = remainder;
} else {
// Now we're ready to invoke the Knuth classical divide algorithm. In this
// case n > 1.
KnuthDiv(U, V, Q, R, m, n);
}
// If the caller wants the quotient
if (Quotient) {
// Set up the Quotient value's memory.
if (Quotient->BitWidth != LHS.BitWidth) {
if (Quotient->isSingleWord())
Quotient->VAL = 0;
else
delete Quotient->pVal;
Quotient->BitWidth = LHS.BitWidth;
if (!Quotient->isSingleWord())
Quotient->pVal = getClearedMemory(lhsWords);
} else
Quotient->clear();
// The quotient is in Q. Reconstitute the quotient into Quotient's low
// order words.
if (lhsWords == 1) {
uint64_t tmp =
uint64_t(Q[0]) | (uint64_t(Q[1]) << (APINT_BITS_PER_WORD / 2));
if (Quotient->isSingleWord())
Quotient->VAL = tmp;
else
Quotient->pVal[0] = tmp;
} else {
assert(!Quotient->isSingleWord() && "Quotient APInt not large enough");
for (unsigned i = 0; i < lhsWords; ++i)
Quotient->pVal[i] =
uint64_t(Q[i*2]) | (uint64_t(Q[i*2+1]) << (APINT_BITS_PER_WORD / 2));
}
}
// If the caller wants the remainder
if (Remainder) {
// Set up the Remainder value's memory.
if (Remainder->BitWidth != RHS.BitWidth) {
if (Remainder->isSingleWord())
Remainder->VAL = 0;
else
delete Remainder->pVal;
Remainder->BitWidth = RHS.BitWidth;
if (!Remainder->isSingleWord())
Remainder->pVal = getClearedMemory(rhsWords);
} else
Remainder->clear();
// The remainder is in R. Reconstitute the remainder into Remainder's low
// order words.
if (rhsWords == 1) {
uint64_t tmp =
uint64_t(R[0]) | (uint64_t(R[1]) << (APINT_BITS_PER_WORD / 2));
if (Remainder->isSingleWord())
Remainder->VAL = tmp;
else
Remainder->pVal[0] = tmp;
} else {
assert(!Remainder->isSingleWord() && "Remainder APInt not large enough");
for (unsigned i = 0; i < rhsWords; ++i)
Remainder->pVal[i] =
uint64_t(R[i*2]) | (uint64_t(R[i*2+1]) << (APINT_BITS_PER_WORD / 2));
}
}
// Clean up the memory we allocated.
delete [] U;
delete [] V;
delete [] Q;
delete [] R;
}
/// Unsigned divide this APInt by APInt RHS.
/// @brief Unsigned division function for APInt.
APInt APInt::udiv(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
// First, deal with the easy case
if (isSingleWord()) {
assert(RHS.VAL != 0 && "Divide by zero?");
return APInt(BitWidth, VAL / RHS.VAL);
}
// Get some facts about the LHS and RHS number of bits and words
uint32_t rhsBits = RHS.getActiveBits();
uint32_t rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1);
assert(rhsWords && "Divided by zero???");
uint32_t lhsBits = this->getActiveBits();
uint32_t lhsWords = !lhsBits ? 0 : (APInt::whichWord(lhsBits - 1) + 1);
// Make a temporary to hold the result
APInt Result(*this);
// Deal with some degenerate cases
if (!lhsWords)
return Result; // 0 / X == 0
else if (lhsWords < rhsWords || Result.ult(RHS)) {
// X / Y with X < Y == 0
memset(Result.pVal, 0, Result.getNumWords() * APINT_WORD_SIZE);
return Result;
} else if (Result == RHS) {
// X / X == 1
memset(Result.pVal, 0, Result.getNumWords() * APINT_WORD_SIZE);
Result.pVal[0] = 1;
return Result;
} else if (lhsWords == 1 && rhsWords == 1) {
// All high words are zero, just use native divide
Result.pVal[0] /= RHS.pVal[0];
return Result;
}
// We have to compute it the hard way. Invoke the Knuth divide algorithm.
APInt Quotient(1,0); // to hold result.
divide(*this, lhsWords, RHS, rhsWords, &Quotient, 0);
return Quotient;
}
/// Unsigned remainder operation on APInt.
/// @brief Function for unsigned remainder operation.
APInt APInt::urem(const APInt& RHS) const {
assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
if (isSingleWord()) {
assert(RHS.VAL != 0 && "Remainder by zero?");
return APInt(BitWidth, VAL % RHS.VAL);
}
// Make a temporary to hold the result
APInt Result(*this);
// Get some facts about the RHS
uint32_t rhsBits = RHS.getActiveBits();
uint32_t rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1);
assert(rhsWords && "Performing remainder operation by zero ???");
// Get some facts about the LHS
uint32_t lhsBits = Result.getActiveBits();
uint32_t lhsWords = !lhsBits ? 0 : (Result.whichWord(lhsBits - 1) + 1);
// Check the degenerate cases
if (lhsWords == 0) {
// 0 % Y == 0
memset(Result.pVal, 0, Result.getNumWords() * APINT_WORD_SIZE);
return Result;
} else if (lhsWords < rhsWords || Result.ult(RHS)) {
// X % Y == X iff X < Y
return Result;
} else if (Result == RHS) {
// X % X == 0;
memset(Result.pVal, 0, Result.getNumWords() * APINT_WORD_SIZE);
return Result;
} else if (lhsWords == 1) {
// All high words are zero, just use native remainder
Result.pVal[0] %= RHS.pVal[0];
return Result;
}
// We have to compute it the hard way. Invoke the Knute divide algorithm.
APInt Remainder(1,0);
divide(*this, lhsWords, RHS, rhsWords, 0, &Remainder);
return Remainder;
}
/// @brief Converts a char array into an integer.
void APInt::fromString(uint32_t numbits, const char *StrStart, uint32_t slen,
uint8_t radix) {
assert((radix == 10 || radix == 8 || radix == 16 || radix == 2) &&
"Radix should be 2, 8, 10, or 16!");
assert(StrStart && "String is null?");
uint32_t size = 0;
// If the radix is a power of 2, read the input
// from most significant to least significant.
if ((radix & (radix - 1)) == 0) {
uint32_t nextBitPos = 0;
uint32_t bits_per_digit = radix / 8 + 2;
uint64_t resDigit = 0;
BitWidth = slen * bits_per_digit;
if (getNumWords() > 1)
pVal = getMemory(getNumWords());
for (int i = slen - 1; i >= 0; --i) {
uint64_t digit = StrStart[i] - '0';
resDigit |= digit << nextBitPos;
nextBitPos += bits_per_digit;
if (nextBitPos >= APINT_BITS_PER_WORD) {
if (isSingleWord()) {
VAL = resDigit;
break;
}
pVal[size++] = resDigit;
nextBitPos -= APINT_BITS_PER_WORD;
resDigit = digit >> (bits_per_digit - nextBitPos);
}
}
if (!isSingleWord() && size <= getNumWords())
pVal[size] = resDigit;
} else { // General case. The radix is not a power of 2.
// For 10-radix, the max value of 64-bit integer is 18446744073709551615,
// and its digits number is 20.
const uint32_t chars_per_word = 20;
if (slen < chars_per_word ||
(slen == chars_per_word && // In case the value <= 2^64 - 1
strcmp(StrStart, "18446744073709551615") <= 0)) {
BitWidth = APINT_BITS_PER_WORD;
VAL = strtoull(StrStart, 0, 10);
} else { // In case the value > 2^64 - 1
BitWidth = (slen / chars_per_word + 1) * APINT_BITS_PER_WORD;
pVal = getClearedMemory(getNumWords());
uint32_t str_pos = 0;
while (str_pos < slen) {
uint32_t chunk = slen - str_pos;
if (chunk > chars_per_word - 1)
chunk = chars_per_word - 1;
uint64_t resDigit = StrStart[str_pos++] - '0';
uint64_t big_base = radix;
while (--chunk > 0) {
resDigit = resDigit * radix + StrStart[str_pos++] - '0';
big_base *= radix;
}
uint64_t carry;
if (!size)
carry = resDigit;
else {
carry = mul_1(pVal, pVal, size, big_base);
carry += add_1(pVal, pVal, size, resDigit);
}
if (carry) pVal[size++] = carry;
}
}
}
}
/// to_string - This function translates the APInt into a string.
std::string APInt::toString(uint8_t radix, bool wantSigned) const {
assert((radix == 10 || radix == 8 || radix == 16 || radix == 2) &&
"Radix should be 2, 8, 10, or 16!");
static const char *digits[] = {
"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"
};
std::string result;
uint32_t bits_used = getActiveBits();
if (isSingleWord()) {
char buf[65];
const char *format = (radix == 10 ? (wantSigned ? "%lld" : "%llu") :
(radix == 16 ? "%llX" : (radix == 8 ? "%llo" : 0)));
if (format) {
if (wantSigned) {
int64_t sextVal = (int64_t(VAL) << (APINT_BITS_PER_WORD-BitWidth)) >>
(APINT_BITS_PER_WORD-BitWidth);
sprintf(buf, format, sextVal);
} else
sprintf(buf, format, VAL);
} else {
memset(buf, 0, 65);
uint64_t v = VAL;
while (bits_used) {
uint32_t bit = v & 1;
bits_used--;
buf[bits_used] = digits[bit][0];
v >>=1;
}
}
result = buf;
return result;
}
if (radix != 10) {
uint64_t mask = radix - 1;
uint32_t shift = (radix == 16 ? 4 : radix == 8 ? 3 : 1);
uint32_t nibbles = APINT_BITS_PER_WORD / shift;
for (uint32_t i = 0; i < getNumWords(); ++i) {
uint64_t value = pVal[i];
for (uint32_t j = 0; j < nibbles; ++j) {
result.insert(0, digits[ value & mask ]);
value >>= shift;
}
}
return result;
}
APInt tmp(*this);
APInt divisor(4, radix);
APInt zero(tmp.getBitWidth(), 0);
size_t insert_at = 0;
if (wantSigned && tmp[BitWidth-1]) {
// They want to print the signed version and it is a negative value
// Flip the bits and add one to turn it into the equivalent positive
// value and put a '-' in the result.
tmp.flip();
tmp++;
result = "-";
insert_at = 1;
}
if (tmp == 0)
result = "0";
else while (tmp.ne(zero)) {
APInt APdigit(1,0);
divide(tmp, tmp.getNumWords(), divisor, divisor.getNumWords(), 0, &APdigit);
uint32_t digit = APdigit.getValue();
assert(digit < radix && "urem failed");
result.insert(insert_at,digits[digit]);
APInt tmp2(tmp.getBitWidth(), 0);
divide(tmp, tmp.getNumWords(), divisor, divisor.getNumWords(), &tmp2, 0);
tmp = tmp2;
}
return result;
}
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