Abstract: A trace module traces changes in a subset of architectural state of a data processing apparatus. A trace generation unit receives input signals from components of the data processing apparatus indicative of a change in the subset of architectural state and generates a number of trace elements indicative of the change to enable a recipient of the trace elements to subsequently reconstruct the subset of architectural state. A table maintained by the trace generation unit identifies an architectural state derivable from previously generated trace elements. The trace generation unit references the table to determine which trace elements to generate. The table reduces the number of trace elements that need to be generated by providing a record of the architectural state which has already been provided to the recipient. Only those trace elements relating to changes in architectural state which are not derivable by the recipient need be generated.

Abstract: The present invention provides a data processing apparatus and method for generating trace signals. The data processing apparatus comprises a component whose behaviour is to be traced, and a trace generation unit for receiving input signals from the component indicative of the behaviour, and for generating from the input signals high priority and low priority trace signals for outputting to a trace receiving device. The trace generation unit is responsive to assertion of a suppression signal from the trace receiving device to suppress generation of the low priority trace signals, with the aim of avoiding overflow of the trace receiving device.