isb

Instruction Synchronization Barrier

ISB {<option>}

Flushes the pipeline and prefetches.

Pseudocode Operation

Instruction pipeline ← flushed; Prefetched instructions ← discarded

Example

ISB

Encoding

Binary Layout

11010101000000110011

31:12

CRm

11:8

1

7

10

6:5

11111

4:0

 

Format System

Opcode 0xD50330DF

Extension Base

Operands

• option
  Option (usually 15)

Related

Other forms of isb

• isb Instruction Synchronization Barrier (Thumb)
• isb Instruction Synchronization Barrier (A32)

More in Base

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0xD50330DF	ISB {<option>|#<imm>}		A64		11010101000000110011 | CRm | 1 | 10 | 11111

Description

Instruction Synchronization Barrier flushes the pipeline in the PE and is a context synchronization event. For more information, see Instruction Synchronization Barrier (ISB).

Operation

InstructionSynchronizationBarrier();
if IsFeatureImplemented(FEAT_BRBE) && BRBEBranchOnISB() then
    BRBEISB();