STI              Set Interrupt Enable Flag           Flags: O D I T S Z A P C
Logic:    IF   1

STI sets the Interrupt Enable Flag, permitting the processor to
recognize maskable interrupts. No other flags are affected. (Non-
maskable interrupts are recognized no matter what the state of the
interrupt enable flag.)

Operands                  Clocks   Transfers  Bytes   Example
no operands                 2          -        1     STI

Notes:         A pending interrupt will not be recognized until
after the instruction following the STI executes.

See also: CLI
See also: STC
See also: CLC
See also: CMC
See also: STD
See also: CLD
See also: Flags

STI Set Interrupt Enable Flag