Differential D2058 Diff 11314 ps/trunk/source/maths/Fixed.h

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ps/trunk/source/maths/Fixed.h

/* Copyright (C) 2013 Wildfire Games.		/* Copyright (C) 2020 Wildfire Games.
* This file is part of 0 A.D.		* This file is part of 0 A.D.
*		*
* 0 A.D. is free software: you can redistribute it and/or modify		* 0 A.D. is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by		* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or		* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.		* (at your option) any later version.
*		*
* 0 A.D. is distributed in the hope that it will be useful,		* 0 A.D. is distributed in the hope that it will be useful,
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#ifndef NDEBUG		#ifndef NDEBUG
#define USE_FIXED_OVERFLOW_CHECKS		#define USE_FIXED_OVERFLOW_CHECKS
#endif		#endif

#if MSC_VERSION		#if MSC_VERSION
// i32*i32 -> i64 multiply: MSVC x86 doesn't optimise i64 multiplies automatically, so use the intrinsic		// i32*i32 -> i64 multiply: MSVC x86 doesn't optimise i64 multiplies automatically, so use the intrinsic
#include <intrin.h>		#include <intrin.h>
#define FIXED_MUL_I64_I32_I32(a, b) (__emul((a), (b)))		#define MUL_I64_I32_I32(a, b)\
		(__emul((a), (b)))
		#define SQUARE_U64_FIXED(a)\
		static_cast<u64>(__emul((a).GetInternalValue(), (a).GetInternalValue()))
#else		#else
#define FIXED_MUL_I64_I32_I32(a, b) ((i64)(a) * (i64)(b))		#define MUL_I64_I32_I32(a, b)\
		static_cast<i64>(a) * static_cast<i64>(b)
		#define SQUARE_U64_FIXED(a)\
		static_cast<u64>(static_cast<i64>((a).GetInternalValue()) * static_cast<i64>((a).GetInternalValue()))
#endif		#endif

//define overflow macros		//define overflow macros
#ifndef USE_FIXED_OVERFLOW_CHECKS		#ifndef USE_FIXED_OVERFLOW_CHECKS

#define CheckSignedSubtractionOverflow(type, left, right, overflowWarning, underflowWarning)		#define CheckSignedSubtractionOverflow(type, left, right, overflowWarning, underflowWarning)
#define CheckSignedAdditionOverflow(type, left, right, overflowWarning, underflowWarning)		#define CheckSignedAdditionOverflow(type, left, right, overflowWarning, underflowWarning)
#define CheckCastOverflow(var, targetType, overflowWarning, underflowWarning)		#define CheckCastOverflow(var, targetType, overflowWarning, underflowWarning)
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CFixed Absolute() const { return CFixed(abs(value)); }		CFixed Absolute() const { return CFixed(abs(value)); }

/**		/**
* Multiply by a CFixed. Likely to overflow if both numbers are large,		* Multiply by a CFixed. Likely to overflow if both numbers are large,
* so we use an ugly name instead of operator* to make it obvious.		* so we use an ugly name instead of operator* to make it obvious.
*/		*/
CFixed Multiply(CFixed n) const		CFixed Multiply(CFixed n) const
{		{
i64 t = FIXED_MUL_I64_I32_I32(value, n.value);		i64 t = MUL_I64_I32_I32(value, n.value);
t >>= fract_bits;		t >>= fract_bits;

CheckCastOverflow(t, T, L"Overflow in CFixed::Multiply(CFixed n)", L"Underflow in CFixed::Multiply(CFixed n)")		CheckCastOverflow(t, T, L"Overflow in CFixed::Multiply(CFixed n)", L"Underflow in CFixed::Multiply(CFixed n)")
return CFixed((T)t);		return CFixed((T)t);
}		}

/**		/**
* Multiply the value by itself. Might overflow.		* Multiply the value by itself. Might overflow.
*/		*/
CFixed Square() const		CFixed Square() const
{		{
return (this).Multiply(this);		return (this).Multiply(this);
}		}

/**		/**
* Compute this*m/d. Must not have d == 0. Won't overflow if the result can be represented as a CFixed.		* Compute this*m/d. Must not have d == 0. Won't overflow if the result can be represented as a CFixed.
*/		*/
CFixed MulDiv(CFixed m, CFixed d) const		CFixed MulDiv(CFixed m, CFixed d) const
{		{
i64 t = FIXED_MUL_I64_I32_I32(value, m.value) / (i64)d.value;		i64 t = MUL_I64_I32_I32(value, m.value) / static_cast<i64>(d.value);
CheckCastOverflow(t, T, L"Overflow in CFixed::Multiply(CFixed n)", L"Underflow in CFixed::Multiply(CFixed n)")		CheckCastOverflow(t, T, L"Overflow in CFixed::Multiply(CFixed n)", L"Underflow in CFixed::Multiply(CFixed n)")
return CFixed((T)t);		return CFixed((T)t);
}		}

CFixed Sqrt() const		CFixed Sqrt() const
{		{
if (value <= 0)		if (value <= 0)
return CFixed(0);		return CFixed(0);
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