bl

Branch with Link

BL <label>

Function call. Branches to label and stores return address in LR (X30).

Pseudocode Operation

LR ← PC + 4
PC ← PC + (SignExtend(imm26, 64) << 2)

Example

BL label

Encoding

Binary Layout

1

31

00101

30:26

imm26

25:0

 

Format Branch

Opcode 0x94000000

Extension Base

Operands

• label
  Label

Related

Other forms of bl

• bl Branch with Link (A32)

More in Base

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x94000000	BL <label>		A64		1 | 00101 | imm26

Description

Branch with Link branches to a PC-relative offset, setting the register X30 to PC+4. It provides a hint that this is a subroutine call.

Operation

if IsFeatureImplemented(FEAT_GCS) && GCSPCREnabled(PSTATE.EL) then
    AddGCSRecord(PC64 + 4);
X[30, 64] = PC64 + 4;

BranchTo(PC64 + offset, BranchType_DIRCALL, FALSE);