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/*
* Copyright (c) 2001, 2003-2005 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Nathan Binkert
*/
#ifndef __BASE_INTMATH_HH__
#define __BASE_INTMATH_HH__
#include <cassert>
#include "base/logging.hh"
#include "base/types.hh"
// Returns the prime number one less than n.
int prevPrime(int n);
// Determine if a number is prime
template <class T>
inline bool
isPrime(const T& n)
{
T i;
if (n == 2 || n == 3)
return true;
// Don't try every odd number to prove if it is a prime.
// Toggle between every 2nd and 4th number.
// (This is because every 6th odd number is divisible by 3.)
for (i = 5; i*i <= n; i += 6) {
if (((n % i) == 0 ) || ((n % (i + 2)) == 0) ) {
return false;
}
}
return true;
}
template <class T>
inline T
leastSigBit(const T& n)
{
return n & ~(n - 1);
}
template <class T>
inline bool
isPowerOf2(const T& n)
{
return n != 0 && leastSigBit(n) == n;
}
inline uint64_t
power(uint32_t n, uint32_t e)
{
if (e > 20)
warn("Warning, power() function is quite slow for large exponents\n");
if (e == 0)
return 1;
uint64_t result = n;
uint64_t old_result = 0;
for (int x = 1; x < e; x++) {
old_result = result;
result *= n;
if (old_result > result)
warn("power() overflowed!\n");
}
return result;
}
inline int
floorLog2(unsigned x)
{
assert(x > 0);
int y = 0;
if (x & 0xffff0000) { y += 16; x >>= 16; }
if (x & 0x0000ff00) { y += 8; x >>= 8; }
if (x & 0x000000f0) { y += 4; x >>= 4; }
if (x & 0x0000000c) { y += 2; x >>= 2; }
if (x & 0x00000002) { y += 1; }
return y;
}
inline int
floorLog2(unsigned long x)
{
assert(x > 0);
int y = 0;
#if defined(__LP64__)
if (x & ULL(0xffffffff00000000)) { y += 32; x >>= 32; }
#endif
if (x & 0xffff0000) { y += 16; x >>= 16; }
if (x & 0x0000ff00) { y += 8; x >>= 8; }
if (x & 0x000000f0) { y += 4; x >>= 4; }
if (x & 0x0000000c) { y += 2; x >>= 2; }
if (x & 0x00000002) { y += 1; }
return y;
}
inline int
floorLog2(unsigned long long x)
{
assert(x > 0);
int y = 0;
if (x & ULL(0xffffffff00000000)) { y += 32; x >>= 32; }
if (x & ULL(0x00000000ffff0000)) { y += 16; x >>= 16; }
if (x & ULL(0x000000000000ff00)) { y += 8; x >>= 8; }
if (x & ULL(0x00000000000000f0)) { y += 4; x >>= 4; }
if (x & ULL(0x000000000000000c)) { y += 2; x >>= 2; }
if (x & ULL(0x0000000000000002)) { y += 1; }
return y;
}
inline int
floorLog2(int x)
{
assert(x > 0);
return floorLog2((unsigned)x);
}
inline int
floorLog2(long x)
{
assert(x > 0);
return floorLog2((unsigned long)x);
}
inline int
floorLog2(long long x)
{
assert(x > 0);
return floorLog2((unsigned long long)x);
}
template <class T>
inline int
ceilLog2(const T& n)
{
if (n == 1)
return 0;
return floorLog2(n - (T)1) + 1;
}
template <class T>
inline T
floorPow2(const T& n)
{
return (T)1 << floorLog2(n);
}
template <class T>
inline T
ceilPow2(const T& n)
{
return (T)1 << ceilLog2(n);
}
template <class T, class U>
inline T
divCeil(const T& a, const U& b)
{
return (a + b - 1) / b;
}
template <class T, class U>
inline T
roundUp(const T& val, const U& align)
{
T mask = (T)align - 1;
return (val + mask) & ~mask;
}
template <class T, class U>
inline T
roundDown(const T& val, const U& align)
{
T mask = (T)align - 1;
return val & ~mask;
}
inline bool
isHex(char c)
{
return (c >= '0' && c <= '9') ||
(c >= 'A' && c <= 'F') ||
(c >= 'a' && c <= 'f');
}
inline bool
isOct(char c)
{
return c >= '0' && c <= '7';
}
inline bool
isDec(char c)
{
return c >= '0' && c <= '9';
}
inline int
hex2Int(char c)
{
if (c >= '0' && c <= '9')
return (c - '0');
if (c >= 'A' && c <= 'F')
return (c - 'A') + 10;
if (c >= 'a' && c <= 'f')
return (c - 'a') + 10;
return 0;
}
#endif // __BASE_INTMATH_HH__