Selective timer control during single-step instruction execution
View Patent ↗A processing device includes a timer and a processor core configured to execute an instruction during a debug session. The processing device further includes a timer control module configured to selectively enable/disable the timer based on a characteristic of the instruction. Another processing device includes a timer, a processor core configured to single step execute a sequence of instructions during a debug session, and a timer control module configured to selectively enable/disable the timer during single step execution of each instruction of the sequence of instructions.
1. A processing device comprising:
a first timer;
a processor core configured to single step execute a sequence of instructions during a debug session;
an external debug interface;
a debug control register accessible via the external debug interface; and
a timer control module configured to selectively enable/disable the first timer during single step execution of each instruction of the sequence of instructions based on a first field of the debug control register, the first field identifying whether the first timer is to be enabled during a single step execution mode of the processor core.
2. The processing device of claim 1 , wherein the first timer is selected from a group consisting of: a watchdog timer; a decrement timer; and a time-base timer.
3. The processing device of claim 1 , further comprising:
a second timer; and
wherein the timer control module is configured to selectively enable/disable the second timer during single step execution of each instruction of the sequence of instructions.
4. The processing device of claim 3 ,
wherein the timer control module further is configured to selectively enable/disable the second timer based on a second field of the debug control register, the second field identifying whether the second timer is to be enabled during the single step execution mode of the processor core.
5. The processing device of claim 1 , wherein the timer control module further is configured to selectively enable/disable the first timer during single step execution of an instruction of the sequence of instructions based on a characteristic of the instruction.
6. The processing device of claim 5 , wherein the timer control module is configured to selectively enable/disable the first timer in response to a comparison of the characteristic to a criterion.
7. The processing device of claim 5 , wherein the characteristic is selected from a group consisting of: an instruction address; an instruction address range; an instruction type; a privilege level; and an instruction source.
8. A method comprising:
receiving an instruction for execution at a processing device during a debug session;
performing a single step execution of the instruction during the debug session;
selectively enabling/disabling a first timer of the processing device during the single step execution based on a first control input, wherein the first control input comprises a first field of a debug control register; and
configuring the first field of the debug control register to have one of a first value or a second value in preparation for the single step execution of the instruction, the first value indicating that the first timer is to be enabled and the second value indicating that the first timer is to be disabled.
9. The method of claim 8 , wherein configuring the first field of the debug control register comprises:
configuring the first field via an external debug interface of the processing device.
10. The method of claim 8 , wherein selectively enabling/disabling the first timer comprises:
determining a value stored at the first field of the debug control register;
selectively enabling/disabling the first timer prior to the single-step execution of the instruction based on the value stored at the first field.
11. The method of claim 8 , further comprising:
disabling the first timer in response to concluding the single step execution of the instruction.
12. The method of claim 8 , further comprising:
selectively enabling/disabling a second timer of the processing device during the single step execution based on a second control input.
13. The method of claim 8 , wherein t the second control input comprises a second field of the debug control register.
14. The method of claim 8 , wherein selectively enabling/disabling the first timer comprises selectively enabling/disabling the first timer further based on a characteristic of the instruction.
15. The method of claim 14 , wherein the characteristic is selected from a group consisting of: an instruction address; an instruction address range; an instruction type; a privilege level; and an instruction source.