fixed_point cos(fixed_point fp){
fixed_point tmp(0);
for( int i = 0; i <= 3; i++){
int32_t tmpSi = (std::pow(-1,i)*0x10000);
fixed_point si(tmpSi);
fixed_point divend = pow(fp, (2*i));
int32_t fac = factorial(2*i);
fixed_point divsor(fac*0x10000);
tmp = tmp + si * (divend/divsor);
}
return tmp;
}
BigInt& BigInt::operator /= (const BigInt &bi)
{
if( bi == 0 )
throw std::logic_error("can't div 0");
bool sign = m_sign;
m_sign = false;
BigInt res(0);
BigInt divsor(bi), count(1);
while( absCompare(divsor) >= 0 )
{
divsor.selfLeftShift(10);//fast
count.selfLeftShift(10);
}
while(absCompare(bi) >= 0)
{
while(absCompare(divsor) < 0)
{
divsor.selfRightShift(1);//slow
count.selfRightShift(1);
}
res += count;
(*this) -= divsor;
}
m_vec = std::move(res.m_vec);
if( m_vec.size() == 1 && m_vec[0] == 0 )
m_sign = false;
else
m_sign = sign ^ bi.m_sign;
return *this;
}
