int m_apm_is_even_mt(M_APM m)
{
int i;
m_apm_enter();
i=m_apm_is_even(m);
m_apm_leave();
return(i);
}
static int Biseven(lua_State *L) /** iseven(x) */
{
M_APM a=Bget(L,1);
lua_pushboolean(L,m_apm_is_integer(a) && m_apm_is_even(a));
return 1;
}
int MAPM::is_even(void) const
{
return m_apm_is_even(cval());
}
/*
* From Knuth, The Art of Computer Programming:
*
* This is the binary GCD algorithm as described
* in the book (Algorithm B)
*/
void m_apm_gcd(M_APM r, M_APM u, M_APM v)
{
M_APM tmpM, tmpN, tmpT, tmpU, tmpV;
int kk, kr, mm;
long pow_2;
/* 'is_integer' will return 0 || 1 */
if ((m_apm_is_integer(u) + m_apm_is_integer(v)) != 2)
{
M_apm_log_error_msg(M_APM_RETURN,
"Warning! \'m_apm_gcd\', Non-integer input");
M_set_to_zero(r);
return;
}
if (u->m_apm_sign == 0)
{
m_apm_absolute_value(r, v);
return;
}
if (v->m_apm_sign == 0)
{
m_apm_absolute_value(r, u);
return;
}
tmpM = M_get_stack_var();
tmpN = M_get_stack_var();
tmpT = M_get_stack_var();
tmpU = M_get_stack_var();
tmpV = M_get_stack_var();
m_apm_absolute_value(tmpU, u);
m_apm_absolute_value(tmpV, v);
/* Step B1 */
kk = 0;
while (TRUE)
{
mm = 1;
if (m_apm_is_odd(tmpU))
break;
mm = 0;
if (m_apm_is_odd(tmpV))
break;
m_apm_multiply(tmpN, MM_0_5, tmpU);
m_apm_copy(tmpU, tmpN);
m_apm_multiply(tmpN, MM_0_5, tmpV);
m_apm_copy(tmpV, tmpN);
kk++;
}
/* Step B2 */
if (mm)
{
m_apm_negate(tmpT, tmpV);
goto B4;
}
m_apm_copy(tmpT, tmpU);
/* Step: */
B3:
m_apm_multiply(tmpN, MM_0_5, tmpT);
m_apm_copy(tmpT, tmpN);
/* Step: */
B4:
if (m_apm_is_even(tmpT))
goto B3;
/* Step B5 */
if (tmpT->m_apm_sign == 1)
m_apm_copy(tmpU, tmpT);
else
m_apm_negate(tmpV, tmpT);
/* Step B6 */
m_apm_subtract(tmpT, tmpU, tmpV);
if (tmpT->m_apm_sign != 0)
goto B3;
/*
* result = U * 2 ^ kk
*/
if (kk == 0)
m_apm_copy(r, tmpU);
else
{
if (kk == 1)
m_apm_multiply(r, tmpU, MM_Two);
if (kk == 2)
m_apm_multiply(r, tmpU, MM_Four);
if (kk >= 3)
{
mm = kk / 28;
kr = kk % 28;
pow_2 = 1L << kr;
if (mm == 0)
{
m_apm_set_long(tmpN, pow_2);
m_apm_multiply(r, tmpU, tmpN);
}
else
{
m_apm_copy(tmpN, MM_One);
m_apm_set_long(tmpM, 0x10000000L); /* 2 ^ 28 */
while (TRUE)
{
m_apm_multiply(tmpT, tmpN, tmpM);
m_apm_copy(tmpN, tmpT);
if (--mm == 0)
break;
}
if (kr == 0)
{
m_apm_multiply(r, tmpU, tmpN);
}
else
{
m_apm_set_long(tmpM, pow_2);
m_apm_multiply(tmpT, tmpN, tmpM);
m_apm_multiply(r, tmpU, tmpT);
}
}
}
}
M_restore_stack(5);
}
