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Int32Math.cpp
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197 lines (171 loc) · 4.27 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\Int32Math.h"
bool
Int32Math::Add(int32 left, int32 right, int32 *pResult)
{
if (sizeof(void *) == 4)
{
// 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;
}
Assert(sizeof(void *) == 8);
int64 result64 = (int64)left + (int64)right;
*pResult = (int32)result64;
return result64 != (int64)(*pResult);
}
bool
Int32Math::Mul(int32 left, int32 right, int32 *pResult)
{
bool fOverflow;
#if _M_IX86
__asm
{
mov eax, left
imul right
seto fOverflow
mov ecx, pResult
mov[ecx], eax
}
#else
int64 result64 = (int64)left * (int64)right;
*pResult = (int32)result64;
fOverflow = (result64 != (int64)(*pResult));
#endif
return fOverflow;
}
bool
Int32Math::Mul(int32 left, int32 right, int32 *pResult, int32* pOverflowValue)
{
bool fOverflow;
#if _M_IX86
__asm
{
mov eax, left
imul right
seto fOverflow
mov ecx, pResult
mov[ecx], eax
mov ecx, pOverflowValue
mov[ecx], edx
}
#else
int64 result64 = (int64)left * (int64)right;
*pResult = (int32)result64;
*pOverflowValue = (int32)(result64 >> 32);
fOverflow = (result64 != (int64)(*pResult));
#endif
return fOverflow;
}
bool
Int32Math::Shl(int32 left, int32 right, int32 *pResult)
{
*pResult = left << (right & 0x1F);
return (left != (int32)((uint32)*pResult >> right));
}
bool
Int32Math::Sub(int32 left, int32 right, int32 *pResult)
{
if(sizeof(void *) == 4)
{
// 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;
}
Assert(sizeof(void *) == 8);
int64 result64 = (int64)left - (int64)right;
*pResult = (int32)result64;
return result64 != (int64)(*pResult);
}
bool
Int32Math::Div(int32 left, int32 right, int32 *pResult)
{
AssertMsg(right != 0, "Divide by zero...");
if (right == -1 && left == INT_MIN)
{
//Special check for INT_MIN/-1
return true;
}
*pResult = left / right;
return false;
}
bool
Int32Math::Mod(int32 left, int32 right, int32 *pResult)
{
AssertMsg(right != 0, "Mod by zero...");
if (right == -1 && left == INT_MIN)
{
//Special check for INT_MIN/-1
return true;
}
*pResult = left % right;
return false;
}
bool
Int32Math::Shr(int32 left, int32 right, int32 *pResult)
{
*pResult = left >> (right & 0x1F);
return false;
}
bool
Int32Math::ShrU(int32 left, int32 right, int32 *pResult)
{
uint32 uResult = ((uint32)left) >> (right & 0x1F);
*pResult = uResult;
return false;
}
bool
Int32Math::And(int32 left, int32 right, int32 *pResult)
{
*pResult = left & right;
return false;
}
bool
Int32Math::Or(int32 left, int32 right, int32 *pResult)
{
*pResult = left | right;
return false;
}
bool
Int32Math::Xor(int32 left, int32 right, int32 *pResult)
{
*pResult = left ^ right;
return false;
}
bool
Int32Math::Neg(int32 val, int32 *pResult)
{
*pResult = -val;
return *pResult == INT_MIN;
}
bool
Int32Math::Not(int32 val, int32 *pResult)
{
*pResult = ~val;
return false;
}
bool
Int32Math::Inc(int32 val, int32 *pResult)
{
*pResult = val + 1;
// Overflow if result ends up less than input
return *pResult <= val;
}
bool
Int32Math::Dec(int32 val, int32 *pResult)
{
*pResult = val - 1;
// Overflow if result ends up greater than input
return *pResult >= val;
}
int32
Int32Math::NearestInRangeTo(const int32 value, const int32 minimum, const int32 maximum) // inclusive
{
Assert(minimum <= maximum);
return minimum >= value ? minimum : maximum <= value ? maximum : value;
}