ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Assembler syntax
SMC #
where:
See Standard assembler syntax fields on page A8-7.
System Instructions
Is a 4-bit immediate value. This is ignored by the ARM processor. It can be used by the SMC
exception handler (Secure Monitor code) to determine what service is being requested, but
this is not recommended.
The pre-UAL syntax SMI is equivalent to SMC.
Operation
if ConditionPassed() then
EncodingSpecificOperations();
if HaveSecurityExt() && CurrentModeIsPrivileged() then
TakeSMCException(); // Secure Monitor Call if privileged
else
UNDEFINED;
Exceptions
Secure Monitor Call.
ARM DDI 0406B Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. B6-19