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| IFF1 || 1-bit || Main Instruction Fetch Flip-Flop || Set when interrupts are enabled, cleared on disable.
When the CPU accepts a maskable interrupt, both IFF1 and IFF2 are automatically resetcleared, inhibiting further interrupts.
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| IFF2 || 1-bit || Stores the state of IFF1 during Non-Maskable Interrupts (NMI) || When an NMI occurs, the processor clears IFF1 to disable interrupts temporarily.