| [SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [K] [L] [M] [N] [P] [Q] [R] [S] [T] [U] [V] [W] EIEM 2nd 3rd 4th EIRR 2nd 3rd 4th EISA ENTRY_INIT ENTRY_IO exit_lock External Interrupt Enable Mask [See EIEM] External Interrupt Request Register [See EIRR] external_interrupt |