Merge remote-tracking branch 'Kernel/master'

Kernel/include_std/cmath

@@ -0,0 +1,181 @@
+/*
+	This file is part of Fennix Kernel.
+
+	Fennix Kernel 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, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix Kernel 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 for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <cfloat>
+#include <type_traits>
+
+namespace std
+{
+	constexpr double sin(double x)
+	{
+		const int NUM_TERMS = 10;
+
+		double result = 0.0;
+		double term = x;
+
+		for (int i = 1; i <= NUM_TERMS; ++i)
+		{
+			result += term;
+			term *= -x * x / ((2 * i) * (2 * i + 1));
+		}
+
+		return result;
+	}
+
+	constexpr float powf(float base, float exp)
+	{
+		float result = 1.0;
+		for (int i = 0; i < (int)exp; ++i)
+			result *= base;
+		return result;
+	}
+
+	constexpr double pow(double base, double exp)
+	{
+		double result = 1.0;
+		for (int i = 0; i < (int)exp; ++i)
+			result *= base;
+		return result;
+	}
+
+	constexpr long double powl(long double base, long double exp)
+	{
+		long double result = 1.0;
+		for (long i = 0; i < (long)exp; ++i)
+			result *= base;
+		return result;
+	}
+
+	constexpr float fabsf(float num)
+	{
+		if (num < 0)
+			return -num;
+		return num;
+	}
+
+	constexpr double fabs(double num)
+	{
+		if (num < 0)
+			return -num;
+		return num;
+	}
+
+	constexpr long double fabsl(long double num)
+	{
+		if (num < 0)
+			return -num;
+		return num;
+	}
+
+	template <class Integer>
+	constexpr bool isinf(Integer num)
+	{
+		union
+		{
+			unsigned long u;
+			double f;
+		} ieee754;
+		ieee754.f = num;
+
+		bool a = ((unsigned)(ieee754.u >> 32) & 0x7fffffff) == 0x7ff00000;
+		bool b = ((unsigned)ieee754.u == 0);
+		return a && b;
+	}
+
+	template <class Integer>
+	constexpr bool isnan(Integer num)
+	{
+		return num != num;
+	}
+
+	template <class Integer>
+	constexpr double fabs(Integer num)
+	{
+		return num < 0 ? -num : num;
+	}
+
+	template <class Integer>
+	constexpr double remainder(Integer x, Integer y)
+	{
+		return x - (int)(x / y) * y;
+	}
+
+	template <class Integer>
+	constexpr double copysign(Integer mag, Integer sgn)
+	{
+		return (sgn < 0) ? -mag : mag;
+	}
+
+	template <class Integer>
+	constexpr bool signbit(Integer num)
+	{
+		return num < 0;
+	}
+
+	template <class Integer>
+	constexpr double fmod(Integer x, Integer y)
+	{
+		double result = std::remainder(std::fabs(x), y = std::fabs(y));
+		if (std::signbit(result))
+			result += (double)y;
+		return std::copysign(result, x);
+	}
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wfloat-equal"
+
+	template <class Integer>
+	constexpr double ceil(Integer num)
+	{
+		// int i = (int)num;
+		// return i + (i < num);
+
+		double remainder = std::fmod((double)num, 1.0);
+		return num >= 0 ? (remainder == 0 ? num : num + 1 - remainder) : num - remainder;
+	}
+
+#pragma GCC diagnostic pop
+
+	template <class Integer>
+	constexpr double trunc(Integer num)
+	{
+		if (std::isinf(num))
+			return num;
+
+		if (std::isnan(num))
+			return num;
+
+		return static_cast<int>(num);
+	}
+
+	template <class Integer>
+	constexpr double exp(Integer num)
+	{
+		double result = 1.0;
+		double term = 1.0;
+
+		for (int i = 1; i <= 10; ++i)
+		{
+			term *= static_cast<double>(num) / i;
+			result += term;
+		}
+
+		return result;
+	}
+}