Low-latency interrupt handling during memory access delay periods in microprocessors

Abstract

A method and processor configured to handle an exception may employ a “retry” signal, which may be associated with a memory access attempt by the processor. The retry signal determines if an exception is to be serviced during a period in which the memory access is delayed. In one embodiment for which the exception is an interrupt, the retry signal is asserted when memory access is delayed and the processor may proceed to service an interrupt request during this period of delayed memory access, regardless of the degree of completion of an instruction by the processor. During a period of delayed memory access, the processor may suspend instruction execution until the memory access becomes available. Upon completion of servicing the interrupt, the processor may resume instruction execution beginning with the last instruction attempted before the suspension of the instruction execution due to the delayed memory access. In one embodiment, the processor may include interrupt handling logic to enable initiation of interrupt service in response to an interrupt request and may further include address selection logic to select an instruction address associated with a delayed memory access.