svc

Supervisor Call (Thumb)

SVC #<imm>

System Call (Thumb encoding).

Pseudocode Operation

SupervisorCallException(imm8)

Example

SVC #16

Encoding

Binary Layout

1101111

15:9

imm8

7:0

Format Thumb System

Opcode 0xDF00

Extension T32 (Thumb)

Operands

imm
ID

Other forms of svc

svc Supervisor Call
svc Supervisor Call (A32)

Across architectures

System Call : how x86, ARM, RISC-V, and PowerISA each do this.

Reference

View in Arm A64 ISA Reference ↗ Arm AArch32 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x0F000000	SVC{<c>}{<q>} {#}<imm>		A32		cond \| 1111 \| imm24
0xDF00	SVC{<c>}{<q>} {#}<imm>		T32		1101111 \| 1 \| imm8

Description

Supervisor Call causes a Supervisor Call exception. For more information, see Supervisor Call (SVC) exception. Software can use this instruction as a call to an operating system to provide a service. In the following cases, the Supervisor Call exception generated by the SVC instruction is taken to Hyp mode: In these cases, the HSR, Hyp Syndrome Register identifies that the exception entry was caused by a Supervisor Call exception, EC value 0x11, see Use of the HSR. The immediate field in the HSR:

Operation

if ConditionPassed() then
    EncodingSpecificOperations();
    AArch32.CheckForSVCTrap(imm32<15:0>);
    AArch32.CallSupervisor(imm32<15:0>);

svc