-//===-- 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 (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.
+// 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) + 32;
+ } else {
+ // get lo portion
+ unsigned Lo = Lo_32(Value);
+ // same as 32 bit value
+ Count = CountLeadingZeros_32(Lo);
+ }
+ }
+#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((uint64_t)C);
- return true;
+// 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);
}
- return false;
+// 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(unsigned Value) {
+ return 63 - CountLeadingZeros_64(Value);
}
+// 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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