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1. Fix last bug in KnuthDiv. All divide tests pass up to 1024 bits now.
2. Clean up comments, style, coding standards, etc. 3. Simplify a constructor. Extended testing revealed some additional bugs in shifting. I'll fix these tomorrow. llvm-svn: 34559
This commit is contained in:
Reid Spencer
parent
a2a4a55915
commit
e2bb0cf83e
@ -2,8 +2,9 @@
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Sheng Zhou and is distributed under the
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// University of Illinois Open Source License. See LICENSE.TXT for details.
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// This file was developed by Sheng Zhou and Reid Spencer and is distributed
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// under the // University of Illinois Open Source License. See LICENSE.TXT
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// for details.
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//
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//===----------------------------------------------------------------------===//
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//
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@ -20,14 +21,13 @@
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#include <cstring>
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#include <cstdlib>
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#ifndef NDEBUG
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#include <iostream>
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#include <iomanip>
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#endif
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using namespace llvm;
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// A utility function for allocating memory, checking for allocation failures,
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// and ensuring the contents is zeroed.
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// and ensuring the contents are zeroed.
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inline static uint64_t* getClearedMemory(uint32_t numWords) {
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uint64_t * result = new uint64_t[numWords];
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assert(result && "APInt memory allocation fails!");
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@ -36,6 +36,7 @@ inline static uint64_t* getClearedMemory(uint32_t numWords) {
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}
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// A utility function for allocating memory and checking for allocation failure.
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// The content is not zero'd
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inline static uint64_t* getMemory(uint32_t numWords) {
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uint64_t * result = new uint64_t[numWords];
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assert(result && "APInt memory allocation fails!");
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@ -60,38 +61,31 @@ APInt::APInt(uint32_t numBits, uint32_t numWords, uint64_t bigVal[])
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assert(BitWidth <= IntegerType::MAX_INT_BITS && "bitwidth too large");
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assert(bigVal && "Null pointer detected!");
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if (isSingleWord())
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VAL = bigVal[0] & (~uint64_t(0ULL) >> (APINT_BITS_PER_WORD - BitWidth));
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VAL = bigVal[0];
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else {
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pVal = getMemory(getNumWords());
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// Calculate the actual length of bigVal[].
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uint32_t maxN = std::max<uint32_t>(numWords, getNumWords());
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uint32_t minN = std::min<uint32_t>(numWords, getNumWords());
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memcpy(pVal, bigVal, (minN - 1) * APINT_WORD_SIZE);
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pVal[minN-1] = bigVal[minN-1] &
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(~uint64_t(0ULL) >>
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(APINT_BITS_PER_WORD - BitWidth % APINT_BITS_PER_WORD));
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if (maxN == getNumWords())
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memset(pVal+numWords, 0, (getNumWords() - numWords) * APINT_WORD_SIZE);
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// Get memory, cleared to 0
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pVal = getClearedMemory(getNumWords());
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// Calculate the number of words to copy
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uint32_t words = std::min<uint32_t>(numWords, getNumWords());
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// Copy the words from bigVal to pVal
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memcpy(pVal, bigVal, words * APINT_WORD_SIZE);
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}
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// Make sure unused high bits are cleared
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clearUnusedBits();
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}
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/// @brief Create a new APInt by translating the char array represented
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/// integer value.
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APInt::APInt(uint32_t numbits, const char StrStart[], uint32_t slen,
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uint8_t radix)
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: BitWidth(numbits), VAL(0) {
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fromString(numbits, StrStart, slen, radix);
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}
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/// @brief Create a new APInt by translating the string represented
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/// integer value.
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APInt::APInt(uint32_t numbits, const std::string& Val, uint8_t radix)
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: BitWidth(numbits), VAL(0) {
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assert(!Val.empty() && "String empty?");
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fromString(numbits, Val.c_str(), Val.size(), radix);
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}
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/// @brief Copy constructor
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APInt::APInt(const APInt& that)
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: BitWidth(that.BitWidth), VAL(0) {
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if (isSingleWord())
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@ -107,8 +101,6 @@ APInt::~APInt() {
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delete[] pVal;
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}
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/// @brief Copy assignment operator. Create a new object from the given
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/// APInt one by initialization.
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APInt& APInt::operator=(const APInt& RHS) {
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assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
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if (isSingleWord())
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@ -118,8 +110,6 @@ APInt& APInt::operator=(const APInt& RHS) {
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return *this;
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}
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/// @brief Assignment operator. Assigns a common case integer value to
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/// the APInt.
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APInt& APInt::operator=(uint64_t RHS) {
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if (isSingleWord())
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VAL = RHS;
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@ -134,15 +124,13 @@ APInt& APInt::operator=(uint64_t RHS) {
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/// "digit" integer array, x[]. x[] is modified to reflect the addition and
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/// 1 is returned if there is a carry out, otherwise 0 is returned.
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/// @returns the carry of the addition.
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static uint64_t add_1(uint64_t dest[],
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uint64_t x[], uint32_t len,
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uint64_t y) {
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static uint64_t add_1(uint64_t dest[], uint64_t x[], uint32_t len, uint64_t y) {
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for (uint32_t i = 0; i < len; ++i) {
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dest[i] = y + x[i];
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if (dest[i] < y)
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y = 1;
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y = 1; // Carry one to next digit.
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else {
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y = 0;
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y = 0; // No need to carry so exit early
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break;
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}
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}
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@ -216,7 +204,7 @@ APInt& APInt::operator+=(const APInt& RHS) {
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}
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/// sub - This function subtracts the integer array x[] by
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/// integer array y[], and returns the borrow-out carry.
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/// integer array y[], and returns the borrow-out.
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static bool sub(uint64_t *dest, const uint64_t *x, const uint64_t *y,
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uint32_t len) {
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bool borrow = false;
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@ -243,10 +231,8 @@ APInt& APInt::operator-=(const APInt& RHS) {
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/// mul_1 - This function performs the multiplication operation on a
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/// large integer (represented as an integer array) and a uint64_t integer.
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/// @returns the carry of the multiplication.
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static uint64_t mul_1(uint64_t dest[],
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uint64_t x[], uint32_t len,
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uint64_t y) {
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// Split y into high 32-bit part and low 32-bit part.
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static uint64_t mul_1(uint64_t dest[], uint64_t x[], uint32_t len, uint64_t y) {
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// Split y into high 32-bit part (hy) and low 32-bit part (ly)
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uint64_t ly = y & 0xffffffffULL, hy = y >> 32;
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uint64_t carry = 0, lx, hx;
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for (uint32_t i = 0; i < len; ++i) {
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@ -277,10 +263,9 @@ static uint64_t mul_1(uint64_t dest[],
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/// mul - This function multiplies integer array x[] by integer array y[] and
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/// stores the result into integer array dest[].
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/// Note the array dest[]'s size should no less than xlen + ylen.
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static void mul(uint64_t dest[], uint64_t x[], uint32_t xlen,
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uint64_t y[], uint32_t ylen) {
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static void mul(uint64_t dest[], uint64_t x[], uint32_t xlen, uint64_t y[],
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uint32_t ylen) {
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dest[xlen] = mul_1(dest, x, xlen, y[0]);
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for (uint32_t i = 1; i < ylen; ++i) {
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uint64_t ly = y[i] & 0xffffffffULL, hy = y[i] >> 32;
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uint64_t carry = 0, lx = 0, hx = 0;
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@ -1053,43 +1038,50 @@ static void KnuthDiv(uint32_t *u, uint32_t *v, uint32_t *q, uint32_t* r,
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if (qp == b || qp*v[n-2] > b*rp + u[j+n-2]) {
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qp--;
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rp += v[n-1];
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if (rp < b && (qp == b || qp*v[n-2] > b*rp + u[j+n-2])) {
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if (rp < b && (qp == b || qp*v[n-2] > b*rp + u[j+n-2]))
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qp--;
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//rp += v[n-1];
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}
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}
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DEBUG(cerr << "KnuthDiv: qp == " << qp << ", rp == " << rp << '\n');
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// D4. [Multiply and subtract.] Replace (u[j+n]u[j+n-1]...u[j]) with
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// (u[j+n]u[j+n-1]..u[j]) - qp * (v[n-1]...v[1]v[0]). This computation
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// consists of a simple multiplication by a one-place number, combined with
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// a subtraction. The digits (u[j+n]...u[j]) should be kept positive;
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bool borrow = false;
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// a subtraction.
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bool isNegative = false;
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for (uint32_t i = 0; i < n; ++i) {
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uint64_t u_tmp = borrow ? uint64_t(u[j+i] - 1) : uint64_t(u[j+i]);
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uint64_t u_tmp = uint64_t(u[j+i]) | (uint64_t(u[j+i+1]) << 32);
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uint64_t subtrahend = uint64_t(qp) * uint64_t(v[i]);
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bool borrow = subtrahend > u_tmp;
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DEBUG(cerr << "KnuthDiv: u_tmp == " << u_tmp
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<< ", subtrahend == " << subtrahend << '\n');
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<< ", subtrahend == " << subtrahend
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<< ", borrow = " << borrow << '\n');
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borrow = subtrahend > u_tmp || (borrow && u[j+i] == 0);
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u[j+i] = u_tmp - subtrahend;
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}
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if (borrow) {
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borrow = u[j+n] == 0; // Was result negative?
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u[j+n]--; // handle the borrow
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uint64_t result = u_tmp - subtrahend;
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uint32_t k = j + i;
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u[k++] = result & (b-1); // subtract low word
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u[k++] = result >> 32; // subtract high word
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while (borrow && k <= m+n) { // deal with borrow to the left
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borrow = u[k] == 0;
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u[k]--;
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k++;
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}
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isNegative |= borrow;
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DEBUG(cerr << "KnuthDiv: u[j+i] == " << u[j+i] << ", u[j+i+1] == " <<
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u[j+i+1] << '\n');
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}
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DEBUG(cerr << "KnuthDiv: after subtraction:");
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DEBUG(for (int i = m+n; i >=0; i--) cerr << " " << u[i]);
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DEBUG(cerr << '\n');
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// if the result of this step is actually negative, (u[j+n]...u[j]) should
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// be left as the true value plus b**(n+1), namely as the b's complement of
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// The digits (u[j+n]...u[j]) should be kept positive; if the result of
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// this step is actually negative, (u[j+n]...u[j]) should be left as the
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// true value plus b**(n+1), namely as the b's complement of
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// the true value, and a "borrow" to the left should be remembered.
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//
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if (borrow) {
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bool carry = true;
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for (uint32_t i = 0; i <= n; ++i) {
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u[j+i] = ~u[j+i] + carry; // b's complement
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carry = u[j+i] == 0;
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if (isNegative) {
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bool carry = true; // true because b's complement is "complement + 1"
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for (uint32_t i = 0; i <= m+n; ++i) {
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u[i] = ~u[i] + carry; // b's complement
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carry = carry && u[i] == 0;
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}
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}
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DEBUG(cerr << "KnuthDiv: after complement:");
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@ -1099,7 +1091,7 @@ static void KnuthDiv(uint32_t *u, uint32_t *v, uint32_t *q, uint32_t* r,
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// D5. [Test remainder.] Set q[j] = qp. If the result of step D4 was
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// negative, go to step D6; otherwise go on to step D7.
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q[j] = qp;
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if (borrow) {
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if (isNegative) {
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// D6. [Add back]. The probability that this step is necessary is very
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// small, on the order of only 2/b. Make sure that test data accounts for
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// this possibility. Decrease q[j] by 1
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@ -1516,12 +1508,12 @@ std::string APInt::toString(uint8_t radix, bool wantSigned) const {
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#ifndef NDEBUG
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void APInt::dump() const
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{
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std::cerr << "APInt(" << BitWidth << ")=" << std::setbase(16);
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cerr << "APInt(" << BitWidth << ")=" << std::setbase(16);
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if (isSingleWord())
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std::cerr << VAL;
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cerr << VAL;
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else for (unsigned i = getNumWords(); i > 0; i--) {
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std::cerr << pVal[i-1] << " ";
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cerr << pVal[i-1] << " ";
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}
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std::cerr << " (" << this->toString(10, false) << ")\n" << std::setbase(10);
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cerr << " (" << this->toString(10, false) << ")\n" << std::setbase(10);
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}
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#endif
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