Data processing device and method of halting exception processing
View Patent ↗A processor begins exception processing in response to an exception event. Exception processing by the processor is halted during exception processing to facilitate debugging. The exception event can be a reset exception event or an interrupt exception event. Normal exception processing by the data processor can be resumed after debugging, or exception processing by the data processor can be aborted to allow the normal execution of instructions by the data processor to resume. An exception event can be selectively treated as an interrupt or a reset.
1. A method of processing an exception event at a data processor device comprising:
setting a programmable indicator to one of a first state or a second state prior to the exception event;
invalidating a first set of state information at the data processor in response to the exception event;
responsive to the exception event and the programmable indicator being set to the first state:
halting processing of the exception event;
placing the data processor device in a debug mode subsequent to invalidating the first set of information; and
maintaining a second set of state information at the data processor for use during the debug mode; and
responsive to the exception event and the programmable indicator being set to the second state:
invalidating the second set of state information; and
continuing processing of the exception event to place the data processing device in a defined state.
2. The method of claim 1 further comprising:
executing a debug operation subsequent to placing the data processor device in the debug mode, wherein the debug operation is executable only during the debug mode.
3. The method of claim 2 further comprising:
resuming exception processing in response to executing the debug operation, where resuming exception processing places the data processor device in the defined state prior to completing exception processing.
4. The method of claim 1 , further comprising initiating execution of application instructions at a defined location based upon the defined state.
5. The method of claim 1 wherein placing the data processor device in the defined state comprises replacing a set of information at the data processor with a defined set of information.
6. The method of claim 5 wherein continuing exception processing further comprises executing a debug routine at the data processor device subsequent to replacing the set of information to achieve the defined state based upon the defined set of information.
7. The method of claim 5 wherein the exception event is a first exception event, the programmable indicator is a first programmable indicator, and the method further comprises:
setting a second programmable indicator to one of the first state or the second state prior to a second exception event;
invalidating the first set of state information at the data processor at the data processor in response to the second exception event;
responsive to the second exception event and the second programmable indicator being set to the first state:
halting processing of the second exception event;
placing the data processor device in the debug mode subsequent to invalidating the first set of information; and
maintaining a third set of state information at the data processor for use during the debug mode; and
responsive to the second exception event and the second programmable indicator being set to the second state:
invalidating the third set of state information; and
continuing processing of the second exception event to place the data processing device in the defined state.
8. The method of claim 7 wherein the first exception event is a reset exception.
9. The method of claim 8 , wherein the reset exception is in response to a computer operating properly timeout.
10. The method of claim 8 wherein the second exception event is an interrupt exception.
11. The method of claim 7 wherein the exception event is in response to an illegal instruction or an illegal address being detected.
12. The method of claim 1 wherein the exception event is a first exception event, and the method further comprises:
invalidating the first set of state information at the data processor in response to a second exception event; and
placing a portion of the data processor device in the defined state in response to the second exception event and without determining whether a programmable indicator is in the first state or the second state.
13. The method of claim 12 , wherein the second exception event is a power on reset exception event.
14. The method of claim 12 , wherein continuing the exception processing comprises completing the exception process by the data processor at a state to initiate execution of application instructions at a defined location.
15. The method of claim 1 , wherein setting the programmable indicator comprises programming a fuse.
16. In a data processor device comprising an integrated circuit, a method comprising:
setting a programmable indicator of the data processor device to one of at least a first state or a second state prior to a reset exception;
initiating exception processing at the data processor device in response to the reset exception;
responsive to the exception event and the programmable indicator being set to the first state, halting the exception processing; and
responsive to the exception event and the programmable indicator being set to the second state, continuing the exception processing without halting.
17. The method of claim 16 , wherein halting execution comprises placing the data processor in a debug mode of operation.
18. The method of claim 16 , wherein continuing the exception processing comprises placing a set of state information in a defined state.
19. A data processing device comprising:
a first node of an integrated circuit to receive a signal indicating an exception event;
a programmable indicator to be set to one of at least a first state or a second state prior to the exception event; and
an exception processing module at the integrated circuit coupled to the first node to initiate execution of an exception processing routine in response to receiving the signal indicating the exception event, the exception processing module comprising:
a first portion of the exception processing routine to implement a first function executed in response to receiving the signal indicating the occurrence of the exception event; and
a second portion of the exception processing routine to be executed upon completion of the first portion to determine whether to halt operation of the data processing device based on the programmable indicator.
20. The data processor device of claim 19 , wherein the exception processing module further comprises:
a third portion of the exception processing routine to be executed in response to the second portion determining to halt the exception processing routine and execution of application instructions at the data processing device; and
a fourth portion of the exception processing routine to be executed in response to the second portion determining not to halt the exception processing routine, the fourth portion continuing the exception processing routine by the data processor device.
21. The data processor device of claim 19 , wherein the module is a first module, the signal is a first signal, the exception event is a first exception event, the exception processing routine is a first exception processing routine, the data processor device further comprising:
a second node of an integrated circuit to receive a second signal indicating a second exception event; and
the exception processing module coupled to the second node to execute a second exception processing routine in response to receiving the second signal indicating the second exception event, the exception processing module further comprising
a first portion of the second exception processing routine to implement the first function in response to receiving the second signal indicating the second exception event; and
a second portion of the second exception processing routine to be executed subsequent to completion of the first portion of the second exception processing call to initiate execution of application instructions after placing the data processor in a defined state, the second portion to be executed without determining whether to halt operation of the second exception processing routine after execution of the first portion.