MathExtras.h revision 2be12faabb3ce2d2d3979c73ac65d466fdea5ec5
1551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer//===-- llvm/Support/MathExtras.h - Useful math functions -------*- C++ -*-===// 263b3afa98460ce38a1c48d3c44ef6edfdaf37b77Misha Brukman// 3b2109ce97881269a610fa4afbcbca350e975174dJohn Criswell// The LLVM Compiler Infrastructure 4b2109ce97881269a610fa4afbcbca350e975174dJohn Criswell// 5b2109ce97881269a610fa4afbcbca350e975174dJohn Criswell// This file was developed by the LLVM research group and is distributed under 6b2109ce97881269a610fa4afbcbca350e975174dJohn Criswell// the University of Illinois Open Source License. See LICENSE.TXT for details. 763b3afa98460ce38a1c48d3c44ef6edfdaf37b77Misha Brukman// 8b2109ce97881269a610fa4afbcbca350e975174dJohn Criswell//===----------------------------------------------------------------------===// 954ea60c69e69b8e5a464a1d7688ceec5c68bacd5Chris Lattner// 1054ea60c69e69b8e5a464a1d7688ceec5c68bacd5Chris Lattner// This file contains some functions that are useful for math stuff. 1154ea60c69e69b8e5a464a1d7688ceec5c68bacd5Chris Lattner// 1254ea60c69e69b8e5a464a1d7688ceec5c68bacd5Chris Lattner//===----------------------------------------------------------------------===// 13cee8f9ae67104576b2028125b56e9ba4856a1d66Chris Lattner 14551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#ifndef LLVM_SUPPORT_MATHEXTRAS_H 15551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#define LLVM_SUPPORT_MATHEXTRAS_H 16cee8f9ae67104576b2028125b56e9ba4856a1d66Chris Lattner 17551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/DataTypes.h" 18cee8f9ae67104576b2028125b56e9ba4856a1d66Chris Lattner 19d0fde30ce850b78371fd1386338350591f9ff494Brian Gaekenamespace llvm { 20d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 2189bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// NOTE: The following support functions use the _32/_64 extensions instead of 2289bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// type overloading so that signed and unsigned integers can be used without 2389bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// ambiguity. 2488c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 2588c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 2688c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// Hi_32 - This function returns the high 32 bits of a 64 bit value. 2788c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline unsigned Hi_32(uint64_t Value) { 2888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return (unsigned)(Value >> 32); 2988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner} 3088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 3188c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// Lo_32 - This function returns the low 32 bits of a 64 bit value. 3288c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline unsigned Lo_32(uint64_t Value) { 3388c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return (unsigned)Value; 3488c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner} 3588c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 3688c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// is?Type - these functions produce optimal testing for integer data types. 3788c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline bool isInt8 (int Value) { return ( signed char )Value == Value; } 3888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline bool isUInt8 (int Value) { return (unsigned char )Value == Value; } 3988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline bool isInt16 (int Value) { return ( signed short)Value == Value; } 4088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline bool isUInt16(int Value) { return (unsigned short)Value == Value; } 4188c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline bool isInt32 (int64_t Value) { return ( signed int )Value == Value; } 4288c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline bool isUInt32(int64_t Value) { return (unsigned int )Value == Value; } 4388c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 4489bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// isMask_32 - This function returns true if the argument is a sequence of ones 4589bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// starting at the least significant bit with the remainder zero (32 bit version.) 4688c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// Ex. isMask_32(0x0000FFFFU) == true. 4788c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline const bool isMask_32(unsigned Value) { 4888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return Value && ((Value + 1) & Value) == 0; 4988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner} 5088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 5189bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// isMask_64 - This function returns true if the argument is a sequence of ones 5289bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// starting at the least significant bit with the remainder zero (64 bit version.) 5388c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline const bool isMask_64(uint64_t Value) { 5488c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return Value && ((Value + 1) & Value) == 0; 5588c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner} 5688c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 5789bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// isShiftedMask_32 - This function returns true if the argument contains a 5889bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// sequence of ones with the remainder zero (32 bit version.) 5988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// Ex. isShiftedMask_32(0x0000FF00U) == true. 6088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline const bool isShiftedMask_32(unsigned Value) { 6188c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return isMask_32((Value - 1) | Value); 6288c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner} 6388c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 6489bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// isShiftedMask_64 - This function returns true if the argument contains a 6589bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// sequence of ones with the remainder zero (64 bit version.) 6688c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline const bool isShiftedMask_64(uint64_t Value) { 6788c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return isMask_64((Value - 1) | Value); 6888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner} 6988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 7089bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// isPowerOf2_32 - This function returns true if the argument is a power of 7189bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// two > 0. Ex. isPowerOf2_32(0x00100000U) == true (32 bit edition.) 7288c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline bool isPowerOf2_32(unsigned Value) { 7388c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return Value && !(Value & (Value - 1)); 7488c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner} 7588c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 76e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner// isPowerOf2_64 - This function returns true if the argument is a power of two 77e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner// > 0 (64 bit edition.) 7888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline bool isPowerOf2_64(uint64_t Value) { 7988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return Value && !(Value & (Value - 1LL)); 8088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner} 8188c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner 82e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner// CountLeadingZeros_32 - this function performs the platform optimal form of 83e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner// counting the number of zeros from the most significant bit to the first one 84e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner// bit. Ex. CountLeadingZeros_32(0x00F000FF) == 8. 85e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner// Returns 32 if the word is zero. 8688c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// CountLeadingZeros_32 - this function performs the platform optimal form 87e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner// of counting the number of zeros from the most significant bit to the first 88e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner// one bit. Ex. CountLeadingZeros_32(0x00F000FF) == 8. 8988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// Returns 32 if the word is zero. 9088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline unsigned CountLeadingZeros_32(unsigned Value) { 9188c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner unsigned Count; // result 92e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner#if __GNUC__ >= 4 93e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner // PowerPC is defined for __builtin_clz(0) 94e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner#if !defined(__ppc__) && !defined(__ppc64__) 95e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner if (!Value) return 32; 96e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner#endif 97e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner Count = __builtin_clz(Value); 98e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner#else 99e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner if (!Value) return 32; 100e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner Count = 0; 101e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner // bisecton method for count leading zeros 102e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner for (unsigned Shift = 32 >> 1; Shift; Shift >>= 1) { 103e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner unsigned Tmp = Value >> Shift; 104e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner if (Tmp) { 105e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner Value = Tmp; 106e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner } else { 107e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner Count |= Shift; 10888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner } 109e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner } 110e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner#endif 11188c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return Count; 11288c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner} 113bb92f6fbf2c36b3530f33eb2e8d1842764ec9fddBrian Gaeke 11488c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// CountLeadingZeros_64 - This function performs the platform optimal form 11589bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// of counting the number of zeros from the most significant bit to the first 11689bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// one bit (64 bit edition.) 11788c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// Returns 64 if the word is zero. 11888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline unsigned CountLeadingZeros_64(uint64_t Value) { 11988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner unsigned Count; // result 120e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner#if __GNUC__ >= 4 121e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner // PowerPC is defined for __builtin_clzll(0) 12289bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner#if !defined(__ppc__) && !defined(__ppc64__) 123e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner if (!Value) return 64; 124e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner#endif 125e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner Count = __builtin_clzll(Value); 126e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner#else 1273b65576527b7e0098a401289f9245eb5266fda31Chris Lattner if (sizeof(long) == sizeof(int64_t)) { 12888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner if (!Value) return 64; 12988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner Count = 0; 13088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner // bisecton method for count leading zeros 13188c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner for (uint64_t Shift = 64 >> 1; Shift; Shift >>= 1) { 13288c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner uint64_t Tmp = Value >> Shift; 13388c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner if (Tmp) { 13488c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner Value = Tmp; 135e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner } else { 136e6ec587059eb142467cc8a5915946a3b308cb9b7Chris Lattner Count |= Shift; 13788c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner } 1383b65576527b7e0098a401289f9245eb5266fda31Chris Lattner } 1393b65576527b7e0098a401289f9245eb5266fda31Chris Lattner } else { 14088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner // get hi portion 14188c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner unsigned Hi = Hi_32(Value); 142cee8f9ae67104576b2028125b56e9ba4856a1d66Chris Lattner 14388c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner // if some bits in hi portion 14488c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner if (Hi) { 14588c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner // leading zeros in hi portion plus all bits in lo portion 146865dc8f64f50b72dbc8acb7851e606357f9d81f1Chris Lattner Count = CountLeadingZeros_32(Hi); 14788c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner } else { 14888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner // get lo portion 14988c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner unsigned Lo = Lo_32(Value); 15088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner // same as 32 bit value 151865dc8f64f50b72dbc8acb7851e606357f9d81f1Chris Lattner Count = CountLeadingZeros_32(Lo)+32; 15288c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner } 1533b65576527b7e0098a401289f9245eb5266fda31Chris Lattner } 1543b65576527b7e0098a401289f9245eb5266fda31Chris Lattner#endif 15588c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return Count; 156e265504e82310266271fa2329b6ef8115bbe8244Chris Lattner} 157e265504e82310266271fa2329b6ef8115bbe8244Chris Lattner 15889bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// Log2_32 - This function returns the floor log base 2 of the specified value, 15989bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// -1 if the value is zero. (32 bit edition.) 16088c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner// Ex. Log2_32(32) == 5, Log2_32(1) == 0, Log2_32(0) == -1 16188c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattnerinline unsigned Log2_32(unsigned Value) { 16288c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return 31 - CountLeadingZeros_32(Value); 16354ea60c69e69b8e5a464a1d7688ceec5c68bacd5Chris Lattner } 16454ea60c69e69b8e5a464a1d7688ceec5c68bacd5Chris Lattner 16589bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// Log2_64 - This function returns the floor log base 2 of the specified value, 16689bfcd34cbd2f4c6bb2cafff0a5c2bff147fae11Chris Lattner// -1 if the value is zero. (64 bit edition.) 1672be12faabb3ce2d2d3979c73ac65d466fdea5ec5Chris Lattnerinline unsigned Log2_64(uint64_t Value) { 16888c606eb0cc5415ed367c24e073f7bb478501d34Chris Lattner return 63 - CountLeadingZeros_64(Value); 169cee8f9ae67104576b2028125b56e9ba4856a1d66Chris Lattner} 170cee8f9ae67104576b2028125b56e9ba4856a1d66Chris Lattner 1717764f4b2e0e550dc23f3c536f236f9abf86879dcBrian Gaeke// Platform-independent wrappers for the C99 isnan() function. 1727764f4b2e0e550dc23f3c536f236f9abf86879dcBrian Gaekeint IsNAN (float f); 1737764f4b2e0e550dc23f3c536f236f9abf86879dcBrian Gaekeint IsNAN (double d); 1747764f4b2e0e550dc23f3c536f236f9abf86879dcBrian Gaeke 175a7d03b466a41e68e11480ae6ca275140fe4c4507Brian Gaeke// Platform-independent wrappers for the C99 isinf() function. 176a7d03b466a41e68e11480ae6ca275140fe4c4507Brian Gaekeint IsInf (float f); 177a7d03b466a41e68e11480ae6ca275140fe4c4507Brian Gaekeint IsInf (double d); 178a7d03b466a41e68e11480ae6ca275140fe4c4507Brian Gaeke 179d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke} // End llvm namespace 180d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 18154ea60c69e69b8e5a464a1d7688ceec5c68bacd5Chris Lattner#endif 182