//===-- llvm/Support/MathExtras.h - Useful math functions -------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file 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; } /// CountLeadingOnes_32 - this function performs the operation of /// counting the number of ones from the most significant bit to the first zero /// bit. Ex. CountLeadingOnes_32(0xFF0FFF00) == 8. /// Returns 32 if the word is all ones. inline unsigned CountLeadingOnes_32(uint32_t Value) { return CountLeadingZeros_32(~Value); } /// 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; } /// CountLeadingOnes_64 - This function performs the operation /// of counting the number of ones from the most significant bit to the first /// zero bit (64 bit edition.) /// Returns 64 if the word is all ones. inline unsigned CountLeadingOnes_64(uint64_t Value) { return CountLeadingZeros_64(~Value); } /// 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 } /// CountTrailingOnes_32 - this function performs the operation of /// counting the number of ones from the least significant bit to the first zero /// bit. Ex. CountTrailingOnes_32(0x00FF00FF) == 8. /// Returns 32 if the word is all ones. inline unsigned CountTrailingOnes_32(uint32_t Value) { return CountTrailingZeros_32(~Value); } /// 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 } /// CountTrailingOnes_64 - This function performs the operation /// of counting the number of ones from the least significant bit to the first /// zero bit (64 bit edition.) /// Returns 64 if the word is all ones. inline unsigned CountTrailingOnes_64(uint64_t Value) { return CountTrailingZeros_64(~Value); } /// 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 uint64_t MinAlign(uint64_t A, uint64_t B) { // The largest power of 2 that divides both A and B. return (A | B) & -(A | B); } } // End llvm namespace #endif