uvxy_field
unsigned long base = uvxy_field(mmioh0, base, 0);
int m_io = uvxy_field(mmioh0, m_io, 0);
int n_io = uvxy_field(mmioh0, n_io, 0);
unsigned long base = uvxy_field(mmioh1, base, 0);
int m_io = uvxy_field(mmioh1, m_io, 0);
int n_io = uvxy_field(mmioh1, n_io, 0);