6.8.1 CPSR Register and Interrupt Intrinsics

The intrinsics in Table 6-7 enable you to get/set the CPSR register and to enable/disable interrupts. All but the _call_swi() function are only available when compiling in ARM mode. Additional intrinsices for ARM assembly instructions are provided in Section 5.14.

Table 6-7 CPSR and Interrupt C/C++ Compiler Intrinsics

C/C++ Compiler Intrinsic Assembly
Instruction		 Description
void _call_swi(unsigned int src); SWI$src Call a software interrupt. The src must be an immediate.
unsigned int dst = _disable_FIQ( ); Cortex-R4/A8:
MRSdst, FAULTMASK
CPSIDf 		Disable FIQ interrupts and return previous FAULTMASK or CPSR setting.
unsigned int dst = _disable_interrupts( ); Cortex-M0:
MRSdst, PRIMASK
CPSIDi
Cortex-M3/M4/R4/A8:
MRSdst, FAULTMASK
CPSIDf 		Disable all interrupts and return previous PRIMASK or FAULTMASK setting. The assembly instructions are dependent on the architecture.
unsigned int dst = _disable_IRQ( ); MRSdst, PRIMASK
CPSIDi 		Disable IRQ interrupts and return previous PRIMASK setting.
unsigned int dst = _enable_FIQ( ); Cortex-R4/A8:
MRSdst, FAULTMASK
CPSIEf 		Enable FIQ interrupts and return previous FAULTMASK or CPSR setting.
unsigned int dst = _enable_interrupts( ); Cortex-M0:
MRSdst, PRIMASK
CPSIEi
Cortex-M3/M4/R4/A8:
MRSdst, FAULTMASK
CPSIEf 		Enable all interrupts and return previous PRIMASK or FAULTMASK setting. The assembly instructions are dependent on the architecture.
unsigned int dst = _enable_IRQ( ); MRSdst, PRIMASK
CPSIEi 		Enable IRQ interrupts and return previous PRIMASK setting.
unsigned int dst = _get_CPSR( ); MRSdst, CPSR Get the CPSR register.
void _restore_interupts(unsigned int src); Cortex-M0:
MSR PRIMASKsrc
Cortex-M3/M4:
MSR FAULTMASKsrc
Cortex-R4:
MSR CPSR_cf ,src 		Restores interrupts to state indicated by value returned from _disable_interrupts. The assembly instructions are dependent on the architecture.
void _set_CPSR(unsigned int src); MSR CPSR, src Set the CPSR register.
void _set_CPSR_flg(unsigned int src); MSRdst, CPSR Set the CPSR flag bits. The src is rotated by the intrinsic.
unsigned int dst = _set_interrupt_priority( unsigned int src) ; Cortex-M0/M3/M4 only:
MRSdst, BASEPRI
MSR BASEPRI,src 		Set interrupt priority and return the previous setting.