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Int64Math.cpp
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158 lines (138 loc) · 3.43 KB
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//-------------------------------------------------------------------------------------------------------
// Copyright (C) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE.txt file in the project root for full license information.
//-------------------------------------------------------------------------------------------------------
#include "CommonCommonPch.h"
#include "Common\Int64Math.h"
#include <intrin.h>
#if _M_X64
#pragma intrinsic(_mul128)
#endif
bool
Int64Math::Add(int64 left, int64 right, int64 *pResult)
{
// Overflow occurs when the result has a different sign from both the left and right operands
*pResult = left + right;
return ((left ^ *pResult) & (right ^ *pResult)) < 0;
}
bool
Int64Math::Mul(int64 left, int64 right, int64 *pResult)
{
#if _M_X64
int64 high;
*pResult = _mul128(left, right, &high);
return high != 0;
#else
*pResult = left * right;
return (left != 0 && right != 0 && (*pResult / left) != right);
#endif
}
bool
Int64Math::Shl(int64 left, int64 right, int64 *pResult)
{
*pResult = left << (right & 63);
return (left != (int64)((uint64)*pResult >> right));
}
bool
Int64Math::Sub(int64 left, int64 right, int64 *pResult)
{
// Overflow occurs when the result has a different sign from the left operand, and the result has the same sign as the
// right operand
*pResult = left - right;
return ((left ^ *pResult) & ~(right ^ *pResult)) < 0;
}
bool
Int64Math::Div(int64 left, int64 right, int64 *pResult)
{
AssertMsg(right != 0, "Divide by zero...");
if (right == -1 && left == MININT64)
{
//Special check for INT64_MIN/-1
return true;
}
*pResult = left / right;
return false;
}
bool
Int64Math::Mod(int64 left, int64 right, int64 *pResult)
{
AssertMsg(right != 0, "Mod by zero...");
if (right == -1 && left == MININT64)
{
//Special check for INT64_MIN/-1
return true;
}
*pResult = left % right;
return false;
}
bool
Int64Math::Shr(int64 left, int64 right, int64 *pResult)
{
*pResult = left >> (right & 63);
return false;
}
bool
Int64Math::ShrU(int64 left, int64 right, int64 *pResult)
{
uint64 uResult = ((uint64)left) >> (right & 63);
*pResult = uResult;
return false;
}
bool
Int64Math::And(int64 left, int64 right, int64 *pResult)
{
*pResult = left & right;
return false;
}
bool
Int64Math::Or(int64 left, int64 right, int64 *pResult)
{
*pResult = left | right;
return false;
}
bool
Int64Math::Xor(int64 left, int64 right, int64 *pResult)
{
*pResult = left ^ right;
return false;
}
bool
Int64Math::Neg(int64 val, int64 *pResult)
{
*pResult = -val;
return *pResult == MININT64;
}
bool
Int64Math::Not(int64 val, int64 *pResult)
{
*pResult = ~val;
return false;
}
bool
Int64Math::Inc(int64 val, int64 *pResult)
{
*pResult = val + 1;
// Overflow if result ends up less than input
return *pResult <= val;
}
bool
Int64Math::Dec(int64 val, int64 *pResult)
{
*pResult = val - 1;
// Overflow if result ends up greater than input
return *pResult >= val;
}
uint64
Int64Math::Log2(int64 val)
{
uint64 uval = (uint64)val;
uint64 ret;
for (ret = 0; uval >>= 1; ret++);
return ret;
}
int64
Int64Math::NearestInRangeTo(const int64 value, const int64 minimum, const int64 maximum) // inclusive
{
Assert(minimum <= maximum);
return minimum >= value ? minimum : maximum <= value ? maximum : value;
}