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// Copyright 2011 Google Inc. All Rights Reserved.
#ifndef ART_SRC_UTILS_H_
#define ART_SRC_UTILS_H_
#include "globals.h"
namespace art {
template<typename T>
static inline bool IsPowerOfTwo(T x) {
return (x & (x - 1)) == 0;
}
template<typename T>
static inline bool IsAligned(T x, int n) {
CHECK(IsPowerOfTwo(n));
return (x & (n - 1)) == 0;
}
template<typename T>
static inline bool IsAligned(T* x, int n) {
return IsAligned(reinterpret_cast<uintptr_t>(x), n);
}
// Check whether an N-bit two's-complement representation can hold value.
static inline bool IsInt(int N, word value) {
CHECK_LT(0, N);
CHECK_LT(N, kBitsPerWord);
word limit = static_cast<word>(1) << (N - 1);
return (-limit <= value) && (value < limit);
}
static inline bool IsUint(int N, word value) {
CHECK_LT(0, N);
CHECK_LT(N, kBitsPerWord);
word limit = static_cast<word>(1) << N;
return (0 <= value) && (value < limit);
}
static inline bool IsAbsoluteUint(int N, word value) {
CHECK_LT(0, N);
CHECK_LT(N, kBitsPerWord);
if (value < 0) value = -value;
return IsUint(N, value);
}
static inline int32_t Low16Bits(int32_t value) {
return static_cast<int32_t>(value & 0xffff);
}
static inline int32_t High16Bits(int32_t value) {
return static_cast<int32_t>(value >> 16);
}
static inline int32_t Low32Bits(int64_t value) {
return static_cast<int32_t>(value);
}
static inline int32_t High32Bits(int64_t value) {
return static_cast<int32_t>(value >> 32);
}
template<typename T>
static inline T RoundDown(T x, int n) {
CHECK(IsPowerOfTwo(n));
return (x & -n);
}
template<typename T>
static inline T RoundUp(T x, int n) {
return RoundDown(x + n - 1, n);
}
// Implementation is from "Hacker's Delight" by Henry S. Warren, Jr.,
// figure 3-3, page 48, where the function is called clp2.
static inline uint32_t RoundUpToPowerOfTwo(uint32_t x) {
x = x - 1;
x = x | (x >> 1);
x = x | (x >> 2);
x = x | (x >> 4);
x = x | (x >> 8);
x = x | (x >> 16);
return x + 1;
}
// Implementation is from "Hacker's Delight" by Henry S. Warren, Jr.,
// figure 5-2, page 66, where the function is called pop.
static inline int CountOneBits(uint32_t x) {
x = x - ((x >> 1) & 0x55555555);
x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
x = (x + (x >> 4)) & 0x0F0F0F0F;
x = x + (x >> 8);
x = x + (x >> 16);
return static_cast<int>(x & 0x0000003F);
}
} // namespace art
#endif // ART_SRC_UTILS_H_
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