Ah yes, takes me back. Page zero is kind of like a large bank of registers with the fast access instructions. The one that I remember puzzling with back in the

Ah yes, takes me back. Page zero is kind of like a large bank of registers with the fast access instructions. The one that I remember puzzling with back in the day was 'SEI' - I mean, why have an interrupt disable bit? Wouldn't it be more sensible to set and clear interrupts, not set and clear disabling interrupts.