| //===-- llvm/Support/MathExtras.h - Useful math functions -------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains some functions that are useful for math stuff. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_SUPPORT_MATHEXTRAS_H |
| #define LLVM_SUPPORT_MATHEXTRAS_H |
| |
| #include "llvm/Support/DataTypes.h" |
| |
| namespace llvm { |
| |
| // NOTE: The following support functions use the _32/_64 extensions instead of |
| // type overloading so that signed and unsigned integers can be used without |
| // ambiguity. |
| |
| /// Hi_32 - This function returns the high 32 bits of a 64 bit value. |
| inline uint32_t Hi_32(uint64_t Value) { |
| return static_cast<uint32_t>(Value >> 32); |
| } |
| |
| /// Lo_32 - This function returns the low 32 bits of a 64 bit value. |
| inline uint32_t Lo_32(uint64_t Value) { |
| return static_cast<uint32_t>(Value); |
| } |
| |
| /// is?Type - these functions produce optimal testing for integer data types. |
| inline bool isInt8 (int64_t Value) { |
| return static_cast<int8_t>(Value) == Value; |
| } |
| inline bool isUInt8 (int64_t Value) { |
| return static_cast<uint8_t>(Value) == Value; |
| } |
| inline bool isInt16 (int64_t Value) { |
| return static_cast<int16_t>(Value) == Value; |
| } |
| inline bool isUInt16(int64_t Value) { |
| return static_cast<uint16_t>(Value) == Value; |
| } |
| inline bool isInt32 (int64_t Value) { |
| return static_cast<int32_t>(Value) == Value; |
| } |
| inline bool isUInt32(int64_t Value) { |
| return static_cast<uint32_t>(Value) == Value; |
| } |
| |
| /// isMask_32 - This function returns true if the argument is a sequence of ones |
| /// starting at the least significant bit with the remainder zero (32 bit |
| /// version). Ex. isMask_32(0x0000FFFFU) == true. |
| inline bool isMask_32(uint32_t Value) { |
| return Value && ((Value + 1) & Value) == 0; |
| } |
| |
| /// isMask_64 - This function returns true if the argument is a sequence of ones |
| /// starting at the least significant bit with the remainder zero (64 bit |
| /// version). |
| inline bool isMask_64(uint64_t Value) { |
| return Value && ((Value + 1) & Value) == 0; |
| } |
| |
| /// isShiftedMask_32 - This function returns true if the argument contains a |
| /// sequence of ones with the remainder zero (32 bit version.) |
| /// Ex. isShiftedMask_32(0x0000FF00U) == true. |
| inline bool isShiftedMask_32(uint32_t Value) { |
| return isMask_32((Value - 1) | Value); |
| } |
| |
| /// isShiftedMask_64 - This function returns true if the argument contains a |
| /// sequence of ones with the remainder zero (64 bit version.) |
| inline bool isShiftedMask_64(uint64_t Value) { |
| return isMask_64((Value - 1) | Value); |
| } |
| |
| /// isPowerOf2_32 - This function returns true if the argument is a power of |
| /// two > 0. Ex. isPowerOf2_32(0x00100000U) == true (32 bit edition.) |
| inline bool isPowerOf2_32(uint32_t Value) { |
| return Value && !(Value & (Value - 1)); |
| } |
| |
| /// isPowerOf2_64 - This function returns true if the argument is a power of two |
| /// > 0 (64 bit edition.) |
| inline bool isPowerOf2_64(uint64_t Value) { |
| return Value && !(Value & (Value - int64_t(1L))); |
| } |
| |
| /// ByteSwap_16 - This function returns a byte-swapped representation of the |
| /// 16-bit argument, Value. |
| inline uint16_t ByteSwap_16(uint16_t Value) { |
| #if defined(_MSC_VER) && !defined(_DEBUG) |
| // The DLL version of the runtime lacks these functions (bug!?), but in a |
| // release build they're replaced with BSWAP instructions anyway. |
| return _byteswap_ushort(Value); |
| #else |
| uint16_t Hi = Value << 8; |
| uint16_t Lo = Value >> 8; |
| return Hi | Lo; |
| #endif |
| } |
| |
| /// ByteSwap_32 - This function returns a byte-swapped representation of the |
| /// 32-bit argument, Value. |
| inline uint32_t ByteSwap_32(uint32_t Value) { |
| #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) |
| return __builtin_bswap32(Value); |
| #elif defined(_MSC_VER) && !defined(_DEBUG) |
| return _byteswap_ulong(Value); |
| #else |
| uint32_t Byte0 = Value & 0x000000FF; |
| uint32_t Byte1 = Value & 0x0000FF00; |
| uint32_t Byte2 = Value & 0x00FF0000; |
| uint32_t Byte3 = Value & 0xFF000000; |
| return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24); |
| #endif |
| } |
| |
| /// ByteSwap_64 - This function returns a byte-swapped representation of the |
| /// 64-bit argument, Value. |
| inline uint64_t ByteSwap_64(uint64_t Value) { |
| #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) |
| return __builtin_bswap64(Value); |
| #elif defined(_MSC_VER) && !defined(_DEBUG) |
| return _byteswap_uint64(Value); |
| #else |
| uint64_t Hi = ByteSwap_32(uint32_t(Value)); |
| uint32_t Lo = ByteSwap_32(uint32_t(Value >> 32)); |
| return (Hi << 32) | Lo; |
| #endif |
| } |
| |
| /// CountLeadingZeros_32 - this function performs the platform optimal form of |
| /// counting the number of zeros from the most significant bit to the first one |
| /// bit. Ex. CountLeadingZeros_32(0x00F000FF) == 8. |
| /// Returns 32 if the word is zero. |
| inline unsigned CountLeadingZeros_32(uint32_t Value) { |
| unsigned Count; // result |
| #if __GNUC__ >= 4 |
| // PowerPC is defined for __builtin_clz(0) |
| #if !defined(__ppc__) && !defined(__ppc64__) |
| if (!Value) return 32; |
| #endif |
| Count = __builtin_clz(Value); |
| #else |
| if (!Value) return 32; |
| Count = 0; |
| // bisecton method for count leading zeros |
| for (unsigned Shift = 32 >> 1; Shift; Shift >>= 1) { |
| uint32_t Tmp = Value >> Shift; |
| if (Tmp) { |
| Value = Tmp; |
| } else { |
| Count |= Shift; |
| } |
| } |
| #endif |
| return Count; |
| } |
| |
| /// CountLeadingZeros_64 - This function performs the platform optimal form |
| /// of counting the number of zeros from the most significant bit to the first |
| /// one bit (64 bit edition.) |
| /// Returns 64 if the word is zero. |
| inline unsigned CountLeadingZeros_64(uint64_t Value) { |
| unsigned Count; // result |
| #if __GNUC__ >= 4 |
| // PowerPC is defined for __builtin_clzll(0) |
| #if !defined(__ppc__) && !defined(__ppc64__) |
| if (!Value) return 64; |
| #endif |
| Count = __builtin_clzll(Value); |
| #else |
| if (sizeof(long) == sizeof(int64_t)) { |
| if (!Value) return 64; |
| Count = 0; |
| // bisecton method for count leading zeros |
| for (unsigned Shift = 64 >> 1; Shift; Shift >>= 1) { |
| uint64_t Tmp = Value >> Shift; |
| if (Tmp) { |
| Value = Tmp; |
| } else { |
| Count |= Shift; |
| } |
| } |
| } else { |
| // get hi portion |
| uint32_t Hi = Hi_32(Value); |
| |
| // if some bits in hi portion |
| if (Hi) { |
| // leading zeros in hi portion plus all bits in lo portion |
| Count = CountLeadingZeros_32(Hi); |
| } else { |
| // get lo portion |
| uint32_t Lo = Lo_32(Value); |
| // same as 32 bit value |
| Count = CountLeadingZeros_32(Lo)+32; |
| } |
| } |
| #endif |
| return Count; |
| } |
| |
| /// CountTrailingZeros_32 - this function performs the platform optimal form of |
| /// counting the number of zeros from the least significant bit to the first one |
| /// bit. Ex. CountTrailingZeros_32(0xFF00FF00) == 8. |
| /// Returns 32 if the word is zero. |
| inline unsigned CountTrailingZeros_32(uint32_t Value) { |
| #if __GNUC__ >= 4 |
| return Value ? __builtin_ctz(Value) : 32; |
| #else |
| static const unsigned Mod37BitPosition[] = { |
| 32, 0, 1, 26, 2, 23, 27, 0, 3, 16, 24, 30, 28, 11, 0, 13, |
| 4, 7, 17, 0, 25, 22, 31, 15, 29, 10, 12, 6, 0, 21, 14, 9, |
| 5, 20, 8, 19, 18 |
| }; |
| return Mod37BitPosition[(-Value & Value) % 37]; |
| #endif |
| } |
| |
| /// CountTrailingZeros_64 - This function performs the platform optimal form |
| /// of counting the number of zeros from the least significant bit to the first |
| /// one bit (64 bit edition.) |
| /// Returns 64 if the word is zero. |
| inline unsigned CountTrailingZeros_64(uint64_t Value) { |
| #if __GNUC__ >= 4 |
| return Value ? __builtin_ctzll(Value) : 64; |
| #else |
| static const unsigned Mod67Position[] = { |
| 64, 0, 1, 39, 2, 15, 40, 23, 3, 12, 16, 59, 41, 19, 24, 54, |
| 4, 64, 13, 10, 17, 62, 60, 28, 42, 30, 20, 51, 25, 44, 55, |
| 47, 5, 32, 65, 38, 14, 22, 11, 58, 18, 53, 63, 9, 61, 27, |
| 29, 50, 43, 46, 31, 37, 21, 57, 52, 8, 26, 49, 45, 36, 56, |
| 7, 48, 35, 6, 34, 33, 0 |
| }; |
| return Mod67Position[(-Value & Value) % 67]; |
| #endif |
| } |
| |
| /// CountPopulation_32 - this function counts the number of set bits in a value. |
| /// Ex. CountPopulation(0xF000F000) = 8 |
| /// Returns 0 if the word is zero. |
| inline unsigned CountPopulation_32(uint32_t Value) { |
| #if __GNUC__ >= 4 |
| return __builtin_popcount(Value); |
| #else |
| uint32_t v = Value - ((Value >> 1) & 0x55555555); |
| v = (v & 0x33333333) + ((v >> 2) & 0x33333333); |
| return ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24; |
| #endif |
| } |
| |
| /// CountPopulation_64 - this function counts the number of set bits in a value, |
| /// (64 bit edition.) |
| inline unsigned CountPopulation_64(uint64_t Value) { |
| #if __GNUC__ >= 4 |
| return __builtin_popcountll(Value); |
| #else |
| uint64_t v = Value - ((Value >> 1) & 0x5555555555555555ULL); |
| v = (v & 0x3333333333333333ULL) + ((v >> 2) & 0x3333333333333333ULL); |
| v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL; |
| return unsigned((uint64_t)(v * 0x0101010101010101ULL) >> 56); |
| #endif |
| } |
| |
| /// Log2_32 - This function returns the floor log base 2 of the specified value, |
| /// -1 if the value is zero. (32 bit edition.) |
| /// Ex. Log2_32(32) == 5, Log2_32(1) == 0, Log2_32(0) == -1, Log2_32(6) == 2 |
| inline unsigned Log2_32(uint32_t Value) { |
| return 31 - CountLeadingZeros_32(Value); |
| } |
| |
| /// Log2_64 - This function returns the floor log base 2 of the specified value, |
| /// -1 if the value is zero. (64 bit edition.) |
| inline unsigned Log2_64(uint64_t Value) { |
| return 63 - CountLeadingZeros_64(Value); |
| } |
| |
| /// Log2_32_Ceil - This function returns the ceil log base 2 of the specified |
| /// value, 32 if the value is zero. (32 bit edition). |
| /// Ex. Log2_32_Ceil(32) == 5, Log2_32_Ceil(1) == 0, Log2_32_Ceil(6) == 3 |
| inline unsigned Log2_32_Ceil(uint32_t Value) { |
| return 32-CountLeadingZeros_32(Value-1); |
| } |
| |
| /// Log2_64 - This function returns the ceil log base 2 of the specified value, |
| /// 64 if the value is zero. (64 bit edition.) |
| inline unsigned Log2_64_Ceil(uint64_t Value) { |
| return 64-CountLeadingZeros_64(Value-1); |
| } |
| |
| /// GreatestCommonDivisor64 - Return the greatest common divisor of the two |
| /// values using Euclid's algorithm. |
| inline uint64_t GreatestCommonDivisor64(uint64_t A, uint64_t B) { |
| while (B) { |
| uint64_t T = B; |
| B = A % B; |
| A = T; |
| } |
| return A; |
| } |
| |
| /// BitsToDouble - This function takes a 64-bit integer and returns the bit |
| /// equivalent double. |
| inline double BitsToDouble(uint64_t Bits) { |
| union { |
| uint64_t L; |
| double D; |
| } T; |
| T.L = Bits; |
| return T.D; |
| } |
| |
| /// BitsToFloat - This function takes a 32-bit integer and returns the bit |
| /// equivalent float. |
| inline float BitsToFloat(uint32_t Bits) { |
| union { |
| uint32_t I; |
| float F; |
| } T; |
| T.I = Bits; |
| return T.F; |
| } |
| |
| /// DoubleToBits - This function takes a double and returns the bit |
| /// equivalent 64-bit integer. |
| inline uint64_t DoubleToBits(double Double) { |
| union { |
| uint64_t L; |
| double D; |
| } T; |
| T.D = Double; |
| return T.L; |
| } |
| |
| /// FloatToBits - This function takes a float and returns the bit |
| /// equivalent 32-bit integer. |
| inline uint32_t FloatToBits(float Float) { |
| union { |
| uint32_t I; |
| float F; |
| } T; |
| T.F = Float; |
| return T.I; |
| } |
| |
| /// Platform-independent wrappers for the C99 isnan() function. |
| int IsNAN(float f); |
| int IsNAN(double d); |
| |
| /// Platform-independent wrappers for the C99 isinf() function. |
| int IsInf(float f); |
| int IsInf(double d); |
| |
| /// MinAlign - A and B are either alignments or offsets. Return the minimum |
| /// alignment that may be assumed after adding the two together. |
| static inline unsigned MinAlign(unsigned A, unsigned B) { |
| // The largest power of 2 that divides both A and B. |
| return (A | B) & -(A | B); |
| } |
| |
| } // End llvm namespace |
| |
| #endif |