441 lines
14 KiB
C++
441 lines
14 KiB
C++
//===-- llvm/Support/MathExtras.h - Useful math functions -------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains some functions that are useful for math stuff.
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//
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//===----------------------------------------------------------------------===//
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/* Capstone Disassembly Engine */
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/* By Nguyen Anh Quynh <aquynh@gmail.com>, 2013-2014 */
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#ifndef CS_LLVM_SUPPORT_MATHEXTRAS_H
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#define CS_LLVM_SUPPORT_MATHEXTRAS_H
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#if !defined(_MSC_VER) || !defined(_KERNEL_MODE)
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#include <stdint.h>
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#endif
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#ifdef _MSC_VER
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# include <intrin.h>
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#endif
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#ifndef __cplusplus
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#if defined (WIN32) || defined (WIN64) || defined (_WIN32) || defined (_WIN64)
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#define inline /* inline */
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#endif
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#endif
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// NOTE: The following support functions use the _32/_64 extensions instead of
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// type overloading so that signed and unsigned integers can be used without
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// ambiguity.
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/// Hi_32 - This function returns the high 32 bits of a 64 bit value.
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static inline uint32_t Hi_32(uint64_t Value) {
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return (uint32_t)(Value >> 32);
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}
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/// Lo_32 - This function returns the low 32 bits of a 64 bit value.
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static inline uint32_t Lo_32(uint64_t Value) {
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return (uint32_t)(Value);
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}
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/// isUIntN - Checks if an unsigned integer fits into the given (dynamic)
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/// bit width.
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static inline bool isUIntN(unsigned N, uint64_t x) {
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return x == (x & (~0ULL >> (64 - N)));
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}
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/// isIntN - Checks if an signed integer fits into the given (dynamic)
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/// bit width.
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//static inline bool isIntN(unsigned N, int64_t x) {
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// return N >= 64 || (-(INT64_C(1)<<(N-1)) <= x && x < (INT64_C(1)<<(N-1)));
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//}
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/// isMask_32 - This function returns true if the argument is a sequence of ones
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/// starting at the least significant bit with the remainder zero (32 bit
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/// version). Ex. isMask_32(0x0000FFFFU) == true.
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static inline bool isMask_32(uint32_t Value) {
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return Value && ((Value + 1) & Value) == 0;
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}
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/// isMask_64 - This function returns true if the argument is a sequence of ones
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/// starting at the least significant bit with the remainder zero (64 bit
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/// version).
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static inline bool isMask_64(uint64_t Value) {
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return Value && ((Value + 1) & Value) == 0;
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}
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/// isShiftedMask_32 - This function returns true if the argument contains a
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/// sequence of ones with the remainder zero (32 bit version.)
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/// Ex. isShiftedMask_32(0x0000FF00U) == true.
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static inline bool isShiftedMask_32(uint32_t Value) {
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return isMask_32((Value - 1) | Value);
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}
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/// isShiftedMask_64 - This function returns true if the argument contains a
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/// sequence of ones with the remainder zero (64 bit version.)
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static inline bool isShiftedMask_64(uint64_t Value) {
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return isMask_64((Value - 1) | Value);
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}
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/// isPowerOf2_32 - This function returns true if the argument is a power of
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/// two > 0. Ex. isPowerOf2_32(0x00100000U) == true (32 bit edition.)
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static inline bool isPowerOf2_32(uint32_t Value) {
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return Value && !(Value & (Value - 1));
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}
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/// CountLeadingZeros_32 - this function performs the platform optimal form of
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/// counting the number of zeros from the most significant bit to the first one
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/// bit. Ex. CountLeadingZeros_32(0x00F000FF) == 8.
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/// Returns 32 if the word is zero.
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static inline unsigned CountLeadingZeros_32(uint32_t Value) {
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unsigned Count; // result
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#if __GNUC__ >= 4
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// PowerPC is defined for __builtin_clz(0)
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#if !defined(__ppc__) && !defined(__ppc64__)
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if (!Value) return 32;
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#endif
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Count = __builtin_clz(Value);
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#else
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unsigned Shift;
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if (!Value) return 32;
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Count = 0;
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// bisection method for count leading zeros
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for (Shift = 32 >> 1; Shift; Shift >>= 1) {
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uint32_t Tmp = Value >> Shift;
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if (Tmp) {
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Value = Tmp;
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} else {
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Count |= Shift;
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}
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}
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#endif
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return Count;
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}
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/// CountLeadingOnes_32 - this function performs the operation of
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/// counting the number of ones from the most significant bit to the first zero
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/// bit. Ex. CountLeadingOnes_32(0xFF0FFF00) == 8.
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/// Returns 32 if the word is all ones.
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static inline unsigned CountLeadingOnes_32(uint32_t Value) {
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return CountLeadingZeros_32(~Value);
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}
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/// CountLeadingZeros_64 - This function performs the platform optimal form
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/// of counting the number of zeros from the most significant bit to the first
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/// one bit (64 bit edition.)
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/// Returns 64 if the word is zero.
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static inline unsigned CountLeadingZeros_64(uint64_t Value) {
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unsigned Count; // result
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#if __GNUC__ >= 4
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// PowerPC is defined for __builtin_clzll(0)
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#if !defined(__ppc__) && !defined(__ppc64__)
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if (!Value) return 64;
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#endif
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Count = __builtin_clzll(Value);
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#else
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#ifndef _MSC_VER
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unsigned Shift;
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if (sizeof(long) == sizeof(int64_t))
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{
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if (!Value) return 64;
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Count = 0;
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// bisection method for count leading zeros
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for (Shift = 64 >> 1; Shift; Shift >>= 1) {
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uint64_t Tmp = Value >> Shift;
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if (Tmp) {
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Value = Tmp;
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} else {
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Count |= Shift;
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}
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}
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}
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else
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#endif
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{
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// get hi portion
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uint32_t Hi = Hi_32(Value);
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// if some bits in hi portion
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if (Hi) {
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// leading zeros in hi portion plus all bits in lo portion
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Count = CountLeadingZeros_32(Hi);
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} else {
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// get lo portion
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uint32_t Lo = Lo_32(Value);
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// same as 32 bit value
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Count = CountLeadingZeros_32(Lo)+32;
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}
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}
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#endif
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return Count;
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}
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/// CountLeadingOnes_64 - This function performs the operation
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/// of counting the number of ones from the most significant bit to the first
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/// zero bit (64 bit edition.)
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/// Returns 64 if the word is all ones.
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static inline unsigned CountLeadingOnes_64(uint64_t Value) {
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return CountLeadingZeros_64(~Value);
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}
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/// CountTrailingZeros_32 - this function performs the platform optimal form of
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/// counting the number of zeros from the least significant bit to the first one
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/// bit. Ex. CountTrailingZeros_32(0xFF00FF00) == 8.
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/// Returns 32 if the word is zero.
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static inline unsigned CountTrailingZeros_32(uint32_t Value) {
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#if __GNUC__ >= 4
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return Value ? __builtin_ctz(Value) : 32;
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#else
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static const unsigned Mod37BitPosition[] = {
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32, 0, 1, 26, 2, 23, 27, 0, 3, 16, 24, 30, 28, 11, 0, 13,
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4, 7, 17, 0, 25, 22, 31, 15, 29, 10, 12, 6, 0, 21, 14, 9,
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5, 20, 8, 19, 18
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};
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// Replace "-Value" by "1+~Value" in the following commented code to avoid
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// MSVC warning C4146
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// return Mod37BitPosition[(-Value & Value) % 37];
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return Mod37BitPosition[((1 + ~Value) & Value) % 37];
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#endif
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}
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/// CountTrailingOnes_32 - this function performs the operation of
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/// counting the number of ones from the least significant bit to the first zero
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/// bit. Ex. CountTrailingOnes_32(0x00FF00FF) == 8.
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/// Returns 32 if the word is all ones.
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static inline unsigned CountTrailingOnes_32(uint32_t Value) {
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return CountTrailingZeros_32(~Value);
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}
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/// CountTrailingZeros_64 - This function performs the platform optimal form
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/// of counting the number of zeros from the least significant bit to the first
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/// one bit (64 bit edition.)
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/// Returns 64 if the word is zero.
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static inline unsigned CountTrailingZeros_64(uint64_t Value) {
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#if __GNUC__ >= 4
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return Value ? __builtin_ctzll(Value) : 64;
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#else
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static const unsigned Mod67Position[] = {
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64, 0, 1, 39, 2, 15, 40, 23, 3, 12, 16, 59, 41, 19, 24, 54,
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4, 64, 13, 10, 17, 62, 60, 28, 42, 30, 20, 51, 25, 44, 55,
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47, 5, 32, 65, 38, 14, 22, 11, 58, 18, 53, 63, 9, 61, 27,
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29, 50, 43, 46, 31, 37, 21, 57, 52, 8, 26, 49, 45, 36, 56,
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7, 48, 35, 6, 34, 33, 0
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};
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// Replace "-Value" by "1+~Value" in the following commented code to avoid
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// MSVC warning C4146
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// return Mod67Position[(-Value & Value) % 67];
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return Mod67Position[((1 + ~Value) & Value) % 67];
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#endif
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}
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/// CountTrailingOnes_64 - This function performs the operation
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/// of counting the number of ones from the least significant bit to the first
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/// zero bit (64 bit edition.)
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/// Returns 64 if the word is all ones.
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static inline unsigned CountTrailingOnes_64(uint64_t Value) {
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return CountTrailingZeros_64(~Value);
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}
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/// CountPopulation_32 - this function counts the number of set bits in a value.
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/// Ex. CountPopulation(0xF000F000) = 8
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/// Returns 0 if the word is zero.
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static inline unsigned CountPopulation_32(uint32_t Value) {
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#if __GNUC__ >= 4
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return __builtin_popcount(Value);
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#else
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uint32_t v = Value - ((Value >> 1) & 0x55555555);
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v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
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return (((v + (v >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24;
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#endif
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}
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/// CountPopulation_64 - this function counts the number of set bits in a value,
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/// (64 bit edition.)
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static inline unsigned CountPopulation_64(uint64_t Value) {
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#if __GNUC__ >= 4
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return __builtin_popcountll(Value);
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#else
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uint64_t v = Value - ((Value >> 1) & 0x5555555555555555ULL);
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v = (v & 0x3333333333333333ULL) + ((v >> 2) & 0x3333333333333333ULL);
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v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL;
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return (uint64_t)((v * 0x0101010101010101ULL) >> 56);
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#endif
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}
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/// Log2_32 - This function returns the floor log base 2 of the specified value,
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/// -1 if the value is zero. (32 bit edition.)
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/// Ex. Log2_32(32) == 5, Log2_32(1) == 0, Log2_32(0) == -1, Log2_32(6) == 2
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static inline unsigned Log2_32(uint32_t Value) {
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return 31 - CountLeadingZeros_32(Value);
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}
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/// Log2_64 - This function returns the floor log base 2 of the specified value,
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/// -1 if the value is zero. (64 bit edition.)
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static inline unsigned Log2_64(uint64_t Value) {
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return 63 - CountLeadingZeros_64(Value);
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}
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/// Log2_32_Ceil - This function returns the ceil log base 2 of the specified
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/// value, 32 if the value is zero. (32 bit edition).
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/// Ex. Log2_32_Ceil(32) == 5, Log2_32_Ceil(1) == 0, Log2_32_Ceil(6) == 3
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static inline unsigned Log2_32_Ceil(uint32_t Value) {
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return 32-CountLeadingZeros_32(Value-1);
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}
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/// Log2_64_Ceil - This function returns the ceil log base 2 of the specified
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/// value, 64 if the value is zero. (64 bit edition.)
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static inline unsigned Log2_64_Ceil(uint64_t Value) {
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return 64-CountLeadingZeros_64(Value-1);
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}
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/// GreatestCommonDivisor64 - Return the greatest common divisor of the two
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/// values using Euclid's algorithm.
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static inline uint64_t GreatestCommonDivisor64(uint64_t A, uint64_t B) {
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while (B) {
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uint64_t T = B;
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B = A % B;
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A = T;
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}
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return A;
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}
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/// BitsToDouble - This function takes a 64-bit integer and returns the bit
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/// equivalent double.
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static inline double BitsToDouble(uint64_t Bits) {
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union {
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uint64_t L;
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double D;
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} T;
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T.L = Bits;
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return T.D;
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}
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/// BitsToFloat - This function takes a 32-bit integer and returns the bit
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/// equivalent float.
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static inline float BitsToFloat(uint32_t Bits) {
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union {
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uint32_t I;
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float F;
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} T;
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T.I = Bits;
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return T.F;
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}
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/// DoubleToBits - This function takes a double and returns the bit
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/// equivalent 64-bit integer. Note that copying doubles around
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/// changes the bits of NaNs on some hosts, notably x86, so this
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/// routine cannot be used if these bits are needed.
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static inline uint64_t DoubleToBits(double Double) {
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union {
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uint64_t L;
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double D;
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} T;
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T.D = Double;
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return T.L;
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}
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/// FloatToBits - This function takes a float and returns the bit
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/// equivalent 32-bit integer. Note that copying floats around
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/// changes the bits of NaNs on some hosts, notably x86, so this
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/// routine cannot be used if these bits are needed.
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static inline uint32_t FloatToBits(float Float) {
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union {
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uint32_t I;
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float F;
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} T;
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T.F = Float;
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return T.I;
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}
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/// MinAlign - A and B are either alignments or offsets. Return the minimum
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/// alignment that may be assumed after adding the two together.
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static inline uint64_t MinAlign(uint64_t A, uint64_t B) {
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// The largest power of 2 that divides both A and B.
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//
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// Replace "-Value" by "1+~Value" in the following commented code to avoid
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// MSVC warning C4146
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// return (A | B) & -(A | B);
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return (A | B) & (1 + ~(A | B));
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}
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/// NextPowerOf2 - Returns the next power of two (in 64-bits)
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/// that is strictly greater than A. Returns zero on overflow.
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static inline uint64_t NextPowerOf2(uint64_t A) {
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A |= (A >> 1);
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A |= (A >> 2);
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A |= (A >> 4);
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A |= (A >> 8);
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A |= (A >> 16);
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A |= (A >> 32);
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return A + 1;
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}
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/// Returns the next integer (mod 2**64) that is greater than or equal to
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/// \p Value and is a multiple of \p Align. \p Align must be non-zero.
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///
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/// Examples:
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/// \code
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/// RoundUpToAlignment(5, 8) = 8
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/// RoundUpToAlignment(17, 8) = 24
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/// RoundUpToAlignment(~0LL, 8) = 0
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/// \endcode
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static inline uint64_t RoundUpToAlignment(uint64_t Value, uint64_t Align) {
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return ((Value + Align - 1) / Align) * Align;
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}
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/// Returns the offset to the next integer (mod 2**64) that is greater than
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/// or equal to \p Value and is a multiple of \p Align. \p Align must be
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/// non-zero.
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static inline uint64_t OffsetToAlignment(uint64_t Value, uint64_t Align) {
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return RoundUpToAlignment(Value, Align) - Value;
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}
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/// abs64 - absolute value of a 64-bit int. Not all environments support
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/// "abs" on whatever their name for the 64-bit int type is. The absolute
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/// value of the largest negative number is undefined, as with "abs".
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static inline int64_t abs64(int64_t x) {
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return (x < 0) ? -x : x;
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}
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/// \brief Sign extend number in the bottom B bits of X to a 32-bit int.
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/// Requires 0 < B <= 32.
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static inline int32_t SignExtend32(uint32_t X, unsigned B) {
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return (int32_t)(X << (32 - B)) >> (32 - B);
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}
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/// \brief Sign extend number in the bottom B bits of X to a 64-bit int.
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/// Requires 0 < B <= 64.
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static inline int64_t SignExtend64(uint64_t X, unsigned B) {
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return (int64_t)(X << (64 - B)) >> (64 - B);
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}
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/// \brief Count number of 0's from the most significant bit to the least
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/// stopping at the first 1.
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///
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/// Only unsigned integral types are allowed.
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///
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/// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are
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/// valid arguments.
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static inline unsigned int countLeadingZeros(int x)
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{
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unsigned count = 0;
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int i;
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const unsigned bits = sizeof(x) * 8;
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for (i = bits; --i; ) {
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if (x < 0) break;
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count++;
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x <<= 1;
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}
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return count;
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}
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#endif
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