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Arm Compiler armclang Reference Guide : __enable_fiq intrinsic

__enable_fiq intrinsic

This intrinsic enables FIQ interrupts.

To use this intrinsic, your source file must contain #include <arm_compat.h>. This is only available for targets in AArch32 state.


Typically, this intrinsic enables FIQ interrupts by clearing the F-bit in the CPSR. However, for v7-M and v8-M.mainline, it clears the fault mask register (FAULTMASK). This intrinsic is not supported in v6-M and v8-M.baseline.


void __enable_fiq(void)


The __enable_fiq intrinsic can only be executed in privileged modes, that is, in non-user modes. In User mode this intrinsic does not change the interrupt flags in the CPSR.