double ldexp(double x, int exp);

typedef struct
{
    double** rows;

} d_mat_struct;

typedef d_mat_struct d_mat_t[1];

#define d_mat_entry(mat,i,j) (*((mat)->rows[i] + (j)))

double __attribute__((noinline)) ldxc1_test(int kappa, int zeros, double ctt, int* expo, d_mat_t r, double* s)
{
    int kappa2 = kappa;
    double tmp = 0.0;

    do
    {
        kappa--;
        if (kappa > zeros + 1)
        {
            tmp = d_mat_entry(r, kappa - 1, kappa - 1) * ctt;
            tmp = ldexp(tmp, (expo[kappa - 1] - expo[kappa2]));
        }
    } while ((kappa >= zeros + 2) && (s[kappa - 1] <= tmp));

    return tmp;
}

#define SIZE 20

int main(void)
{
    int kappa = SIZE - 1;
    int zeros = 1;
    double ctt = 2;

    int expo[SIZE];
    double s[SIZE];
    double rows_data[SIZE][SIZE];
    double* rows[SIZE];

    for (int i = 0; i < SIZE; i++)
        rows[i] = rows_data[i];

    d_mat_t r = { rows };

    ldxc1_test(kappa, zeros, ctt, expo, r, s);
    return 0;
}