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Enable Interrupts

General Form

STI

Syntax

STI Dreg ; /* previous state of IMASK restored from Dreg (a) */

Syntax Terminology

Dreg: R7–0

Instruction Length

In the syntax, comment (a) identifies 16-bit instruction length.

Functional Description

The Enable Interrupts instruction globally enables interrupts by restoring the previous state of the interrupt system back into IMASK.

Flags Affected

None

Required Mode

The Enable Interrupts instruction executes only in Supervisor mode. If execution is attempted in User mode, the instruction produces an Illegal Use of Protected Resource exception.

Parallel Issue

The Enable Interrupts instruction cannot be issued in parallel with other instructions.

Example

sti r3 ;

Also See

Special Applications

This instruction is often located after an IDLE instruction so that it will execute after a wake-up event from the idle state.