Method Tan

TSMath.cpp:301–344

}

float Terathon::Tan(float x)
{
	#ifndef TERATHON_NO_SIMD

		float	cosine, sine;

		vec_float b = VecMulScalar(VecAndc(VecLoadScalar(&x), VecFloatGetMinusZero()), VecLoadScalarConstant<0x4222F983>());
		vec_float i = VecPositiveFloorScalar(b);
		b = VecMulScalar(VecSubScalar(b, i), VecLoadScalarConstant<0x3CC90FDB>());

		const TrigPair& cossin = GetTrigTable()[VecTruncateConvert(i) & 255];
		vec_float cosine_alpha = VecLoadScalar(&cossin.x);
		vec_float sine_alpha = VecLoadScalar(&cossin.y);

		vec_float b2 = VecMulScalar(b, b);
		vec_float sine_beta = VecNmsubScalar(VecMulScalar(b, b2), VecNmsubScalar(b2, VecLoadScalarConstant<0x3E2AAAAB>(), VecLoadScalarConstant<0x3C088889>()), b);
		vec_float cosine_beta = VecNmsubScalar(b2, VecNmsub(b2, VecLoadScalarConstant<0x3D2AAAAB>(), VecLoadScalarConstant<0x3F000000>()), VecLoadScalarConstant<0x3F800000>());

		VecStoreX(VecMaddScalar(sine_alpha, cosine_beta, VecMulScalar(cosine_alpha, sine_beta)), &sine);
		VecStoreX(VecSubScalar(VecMulScalar(cosine_alpha, cosine_beta), VecMulScalar(sine_alpha, sine_beta)), &cosine);

		float result = sine / cosine;
		return ((x < 0.0F) ? -result : result);

	#else

		float b = Fabs(x) * 40.74366543F;	// 256 / tau
		float i = PositiveFloor(b);
		b = (b - i) * 0.0245436926F;		// tau / 256

		const TrigPair& cossin_alpha = GetTrigTable()[int32(i) & 255];

		float b2 = b * b;
		float sine_beta = b - b * b2 * (0.1666666667F - b2 * 0.008333333333F);
		float cosine_beta = 1.0F - b2 * (0.5F - b2 * 0.04166666667F);

		float sine = cossin_alpha.y * cosine_beta + cossin_alpha.x * sine_beta;
		float cosine = cossin_alpha.x * cosine_beta - cossin_alpha.y * sine_beta;

		float result = sine / cosine;
		return ((x < 0.0F) ? -result : result);

	#endif
}

void Terathon::CosSin(float x, float *c, float *s)
{