CHECK POINTING A SHIFT REGISTER

摘要

A hardware structure provides a way for check pointing a main shift register one or more times. The hardware structure includes an extended shift register used to store the data elements most recently shifted onto the main shift register which has an extra data position for each check point. An update history shift register has a data position for each check point which is used to store information indicating whether the extended shift register was updated. Check point generation logic derives each check point by selecting a subset of the data elements stored in the extended shift register based on the information stored in the update history shift register.

主权项

1. A hardware structure configured to derive one or more check points for a main shift register, the check points being triggered by trigger events, the hardware structure comprising:
an extended shift register having a plurality of data positions for storing data elements, the plurality of data positions including a first subset of data positions which represent the main shift register and an additional data position for each check point; an update history shift register having a data position for each check point, each data position of the update history shift register storing information indicating whether the extended shift register was updated in a same clock cycle as a particular check point trigger event; and check point generation logic configured to derive each check point by selecting a subset of the plurality of data positions of the extended shift register based on the information stored in the update history shift register.