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Quality of Service attribute

This attribute supports Quality of Service (QoS) schemes.

The bus protocol does not specify the exact use of the QoS identifier but recommends that it is used as a priority indicator.

The method set_qos() sets this attribute to the value passed as argument. The method get_qos() returns the value of this attribute.

The default value of this attribute is 0, which indicates that the interface is not participating in any QoS scheme.

This attribute is specific to the AXI4 and ACE buses. It is ignored for transactions modeling transfers on the AXI3, AHB and APB buses.

For AXI4 and ACE this indicator attribute value must be between 0 and 15 inclusive.