include/llvm/Support/MathExtras.h - llvm - Git at Google

 //===-- 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));
 }

 // 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
	//===-- 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));
	}

	// 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