-//===-- Support/MathExtras.h - Useful math functions ------------*- C++ -*-===//
-//
+//===-- 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 SUPPORT_MATHEXTRAS_H
-#define SUPPORT_MATHEXTRAS_H
+#ifndef LLVM_SUPPORT_MATHEXTRAS_H
+#define LLVM_SUPPORT_MATHEXTRAS_H
-#include "Support/DataTypes.h"
+#include "llvm/Support/DataTypes.h"
namespace llvm {
-inline unsigned log2(uint64_t C) {
- unsigned getPow;
- for (getPow = 0; C > 1; ++getPow)
- C >>= 1;
- return getPow;
+// 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 static_cast<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 static_cast<unsigned>(Value);
+}
+
+// is?Type - these functions produce optimal testing for integer data types.
+inline bool isInt8 (int Value) {
+ return static_cast<signed char>(Value) == Value;
+}
+inline bool isUInt8 (int Value) {
+ return static_cast<unsigned char>(Value) == Value;
+}
+inline bool isInt16 (int Value) {
+ return static_cast<signed short>(Value) == Value;
+}
+inline bool isUInt16(int Value) {
+ return static_cast<unsigned short>(Value) == Value;
+}
+inline bool isInt32 (int64_t Value) {
+ return static_cast<signed int>(Value) == Value;
+}
+inline bool isUInt32(int64_t Value) {
+ return static_cast<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 - int64_t(1L)));
+}
+
+// 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;
}
-inline bool isPowerOf2(int64_t C, unsigned &getPow) {
- if (C < 0) C = -C;
- if (C > 0 && C == (C & ~(C - 1))) {
- getPow = log2(static_cast<uint64_t>(C));
- return true;
+// 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));
+}
- return false;
+// 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(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);
+}
+
+// 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(unsigned 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);
+}
+
+// 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
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