brk

Breakpoint

BRK #<imm>

Generates a Breakpoint instruction exception.

Pseudocode Operation

AArch64.SystemSideEffect()
ESR_ELx.EC ← 0x3C
ESR_ELx.ISS ← imm16
TakeSynchronousException(Breakpoint)

Example

BRK #16

Encoding

Binary Layout

11010100

31:24

001

23:21

imm16

20:5

000

4:2

1:0

Format Exception

Opcode 0xD4200000

Extension Base

Operands

imm
ID (16-bit)

Across architectures

Breakpoint Trap : how x86, ARM, RISC-V, and PowerISA each do this.

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0xD4200000	BRK #<imm>		A64		11010100 \| 001 \| imm16 \| 000 \| 00

Description

Breakpoint instruction. A BRK instruction generates a Breakpoint Instruction exception. The PE records the exception in ESR_ELx, using the EC value 0x3C, and captures the value of the immediate argument in ESR_ELx.ISS. Within a guarded memory region, while PSTATE.BTYPE != 0b00, a BRK instruction will not generate a Branch Target Exception and will generate a Breakpoint Instruction exception as normal. For more information, see PSTATE.BTYPE.

Operation

AArch64.SoftwareBreakpoint(imm16);

brk