dolphin/Source/Core/Common/Src/MathUtil.h

// Copyright (C) 2003 Dolphin Project.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/

#ifndef _MATH_UTIL_H_
#define _MATH_UTIL_H_

#include "Common.h"

#include <vector>
#include "FPURoundMode.h"

namespace MathUtil
{

static const u64 DOUBLE_SIGN = 0x8000000000000000ULL,
	DOUBLE_EXP  = 0x7FF0000000000000ULL,
	DOUBLE_FRAC = 0x000FFFFFFFFFFFFFULL,
	DOUBLE_ZERO = 0x0000000000000000ULL;

static const u32 FLOAT_SIGN = 0x80000000,
	FLOAT_EXP  = 0x7F800000,
	FLOAT_FRAC = 0x007FFFFF,
	FLOAT_ZERO = 0x00000000;

union IntDouble {
	double d;
	u64 i;
};
union IntFloat {
	float f;
	u32 i;
};

inline bool IsNAN(double d)
{
	IntDouble x; x.d = d;
	return ( ((x.i & DOUBLE_EXP) == DOUBLE_EXP) &&
			 ((x.i & DOUBLE_FRAC) != DOUBLE_ZERO) );
}

inline bool IsQNAN(double d)
{
	IntDouble x; x.d = d;
	return ( ((x.i & DOUBLE_EXP) == DOUBLE_EXP) &&
		     ((x.i & 0x0007fffffffffffULL) == 0x000000000000000ULL) &&
		     ((x.i & 0x000800000000000ULL) == 0x000800000000000ULL) );
}

inline bool IsSNAN(double d)
{
	IntDouble x; x.d = d;
	return( ((x.i & DOUBLE_EXP) == DOUBLE_EXP) &&
			((x.i & DOUBLE_FRAC) != DOUBLE_ZERO) &&
			((x.i & 0x0008000000000000ULL) == DOUBLE_ZERO) );
}

inline float FlushToZero(float f)
{
	IntFloat x; x.f = f;
	if ((x.i & FLOAT_EXP) == 0)
		x.i &= FLOAT_SIGN;  // turn into signed zero
	return x.f;
}

inline double FlushToZeroAsFloat(double d)
{
	IntDouble x; x.d = d;
	if ((x.i & DOUBLE_EXP) < 0x3800000000000000ULL)
		x.i &= DOUBLE_SIGN;  // turn into signed zero
	return x.d;
}

enum PPCFpClass
{
	PPC_FPCLASS_QNAN = 0x11,
	PPC_FPCLASS_NINF = 0x9,
	PPC_FPCLASS_NN   = 0x8,
	PPC_FPCLASS_ND   = 0x18,
	PPC_FPCLASS_NZ   = 0x12,
	PPC_FPCLASS_PZ   = 0x2,
	PPC_FPCLASS_PD   = 0x14,
	PPC_FPCLASS_PN   = 0x4,
	PPC_FPCLASS_PINF = 0x5,
};

// Uses PowerPC conventions for the return value, so it can be easily
// used directly in CPU emulation.
u32 ClassifyDouble(double dvalue);
// More efficient float version.
u32 ClassifyFloat(float fvalue);

template<class T>
struct Rectangle
{
	T left;
	T top;
	T right;
	T bottom;

	Rectangle()
	{ }

	Rectangle(T theLeft, T theTop, T theRight, T theBottom)
		: left(theLeft), top(theTop), right(theRight), bottom(theBottom)
	{ }

	T GetWidth() const { return abs(right - left); }
	T GetHeight() const { return abs(bottom - top); }

	// If the rectangle is in a coordinate system with a lower-left origin, use
	// this Clamp.
	void ClampLL(T x1, T y1, T x2, T y2)
	{
		if (left < x1) left = x1;
		if (right > x2) right = x2;
		if (top > y1) top = y1;
		if (bottom < y2) bottom = y2;
	}

	// If the rectangle is in a coordinate system with an upper-left origin,
	// use this Clamp.
	void ClampUL(T x1, T y1, T x2, T y2) 
	{
		if (left < x1) left = x1;
		if (right > x2) right = x2;
		if (top < y1) top = y1;
		if (bottom > y2) bottom = y2;
	}
};

}  // namespace MathUtil

inline float pow2f(float x) {return x * x;}
inline double pow2(double x) {return x * x;}

float MathFloatVectorSum(const std::vector<float>&);

#define ROUND_UP(x, a)		(((x) + (a) - 1) & ~((a) - 1))
#define ROUND_DOWN(x, a)	((x) & ~((a) - 1))

template <typename T>
T Log2(T val)
{
#if defined(_M_X64)
	T result;
	asm
	(
		"bsr %1, %0"
		: "=r"(result)
		: "r"(val)
	);
	return result;
#else
	T result = -1;
	while (val != 0)
	{
		val >>= 1;
		++result;
	}
	return result;
#endif
}

// Tiny matrix/vector library.
// Used for things like Free-Look in the gfx backend.

class Matrix33
{
public:
    static void LoadIdentity(Matrix33 &mtx);

    // set mtx to be a rotation matrix around the x axis
    static void RotateX(Matrix33 &mtx, float rad);
    // set mtx to be a rotation matrix around the y axis
    static void RotateY(Matrix33 &mtx, float rad);

    // set result = a x b
    static void Multiply(const Matrix33 &a, const Matrix33 &b, Matrix33 &result);
    static void Multiply(const Matrix33 &a, const float vec[3], float result[3]);

    float data[9];
};

class Matrix44
{
public:
    static void LoadIdentity(Matrix44 &mtx);
    static void LoadMatrix33(Matrix44 &mtx, const Matrix33 &m33);
    static void Set(Matrix44 &mtx, const float mtxArray[16]);

    static void Translate(Matrix44 &mtx, const float vec[3]);

    static void Multiply(const Matrix44 &a, const Matrix44 &b, Matrix44 &result);

    float data[16];
};

#endif // _MATH_UTIL_H_