| //===-- 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 unsigned Hi_32(uint64_t Value) { |
| return (unsigned)(Value >> 32); |
| } |
| |
| // Lo_32 - This function returns the low 32 bits of a 64 bit value. |
| inline unsigned Lo_32(uint64_t Value) { |
| return (unsigned)Value; |
| } |
| |
| // is?Type - these functions produce optimal testing for integer data types. |
| inline bool isInt8 (int Value) { return ( signed char )Value == Value; } |
| inline bool isUInt8 (int Value) { return (unsigned char )Value == Value; } |
| inline bool isInt16 (int Value) { return ( signed short)Value == Value; } |
| inline bool isUInt16(int Value) { return (unsigned short)Value == Value; } |
| inline bool isInt32 (int64_t Value) { return ( signed int )Value == Value; } |
| inline bool isUInt32(int64_t Value) { return (unsigned int )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 const bool isMask_32(unsigned 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 const 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 const bool isShiftedMask_32(unsigned 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 const 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(unsigned 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 - 1LL)); |
| } |
| |
| // ByteSwap_16 - This function returns a byte-swapped representation of the |
| // 16-bit argument, Value. |
| inline unsigned short ByteSwap_16(unsigned short Value) { |
| unsigned short Hi = Value << 8; |
| unsigned short Lo = Value >> 8; |
| return Hi | Lo; |
| } |
| |
| // ByteSwap_32 - This function returns a byte-swapped representation of the |
| // 32-bit argument, Value. |
| inline unsigned ByteSwap_32(unsigned Value) { |
| unsigned Byte0 = Value & 0x000000FF; |
| unsigned Byte1 = Value & 0x0000FF00; |
| unsigned Byte2 = Value & 0x00FF0000; |
| unsigned Byte3 = Value & 0xFF000000; |
| return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24); |
| } |
| |
| // ByteSwap_64 - This function returns a byte-swapped representation of the |
| // 64-bit argument, Value. |
| inline uint64_t ByteSwap_64(uint64_t Value) { |
| uint64_t Hi = ByteSwap_32(unsigned(Value)); |
| uint64_t Lo = ByteSwap_32(unsigned(Value >> 32)); |
| return (Hi << 32) | Lo; |
| } |
| |
| // 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(unsigned 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) { |
| unsigned 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 (uint64_t Shift = 64 >> 1; Shift; Shift >>= 1) { |
| uint64_t Tmp = Value >> Shift; |
| if (Tmp) { |
| Value = Tmp; |
| } else { |
| Count |= Shift; |
| } |
| } |
| } else { |
| // get hi portion |
| unsigned 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 |
| unsigned 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(unsigned Value) { |
| return 32 - CountLeadingZeros_32(~Value & (Value - 1)); |
| } |
| |
| // 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) { |
| return 64 - CountLeadingZeros_64(~Value & (Value - 1)); |
| } |
| |
| // 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(unsigned Value) { |
| unsigned x, t; |
| x = Value - ((Value >> 1) & 0x55555555); |
| t = ((x >> 2) & 0x33333333); |
| x = (x & 0x33333333) + t; |
| x = (x + (x >> 4)) & 0x0F0F0F0F; |
| x = x + (x << 8); |
| x = x + (x << 16); |
| return x >> 24; |
| } |
| |
| // CountPopulation_64 - this function counts the number of set bits in a value, |
| // (64 bit edition.) |
| inline unsigned CountPopulation_64(uint64_t Value) { |
| return CountPopulation_32(unsigned(Value >> 32)) + |
| CountPopulation_32(unsigned(Value)); |
| } |
| |
| // 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 |
| inline unsigned Log2_32(unsigned 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); |
| } |
| |
| // 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); |
| |
| } // End llvm namespace |
| |
| #endif |