2.2.10 Exclusive attribute

This attribute selects exclusive access, and the response attribute indicates the success or failure of the exclusive access.

The method set_exclusive() must set this attribute to the value passed as argument. The method is_exclusive() must return the value of this attribute.

The AMBA-PV package provides an exclusive monitor model that supports exclusive access and that can be added before your slave. It removes the requirement for your slave to model additional logic to support exclusive access.

Arm recommends that masters do not use the direct memory interface for exclusive accesses.

The address of an exclusive access must be aligned to the total number of bytes in the transaction as determined by the value of the burst size attribute multiplied by the value of the burst length attribute.

The number of bytes to be transferred in an exclusive access must be a power of 2 and less than or equal to 128.

Arm recommends that every exclusive write has an earlier outstanding exclusive read with the same value for the ID attribute.

Arm recommends that the value of the address, burst size, and burst length attributes of an exclusive write with a given value for the ID attribute is the same as the value of the address, burst size, and burst length attributes of the preceding exclusive read with the same value for the ID attribute.

An AMBA_PV_EXOKAY value for the response attribute can only be given to an exclusive access.

This attribute must not have the value true together with the locked attribute.

The default value of this attribute must be false.

This attribute is specific to the AXI and ACE buses. It is ignored for transactions modeling transfers on the AHB and APB buses.

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