Outline

Unlock the CPU.

C format

ER unl_cpu ( void ); ER iunl_cpu ( void );

Assembly format

CALL !!_unl_cpu CALL !!_iunl_cpu

Parameter(s)

None.

Explanation

These service calls change the system status to the CPU unlocked state.

As a result, acknowledge processing of maskable interrupts prohibited through issuance of either loc_cpu or iloc_cpu is enabled, and the restriction on service call issuance is released.

If a maskable interrupt is created during the interval from when either loc_cpu or iloc_cpu is issued until this service call is issued, the RI78V4 delays transition to the relevant interrupt processing (interrupt handler) until this service call is issued.

Note 1 This service call does not perform queuing of cancellation requests. If the system is in the CPU unlocked state, therefore, no processing is performed but it is not handled as an error.

Note 2 The RI78V4 implements enabling of maskable interrupt acknowledgment bu manipulating the interrupt mask flag register (MKxx) and the in-service priority flag (ISPx) of the program status word (PSW). Therefore, manipulating of these registers from the processing program is prohibited from when loc_cpu or iloc_cpu is issued until this service call is issued.

Return value

Macro	Value	Description
E_OK	0	Normal completion.