Managing and maintaining multiple debug contexts in a debug execution mode for real-time processors

A method of debugging program code executing on a processor configured with a debug controller performing a debug monitor function, the program code including a plurality of code sections, each code section associated with an execution priority level, the method comprising:

• executing a first code section having a first execution priority on the processor while allowing interrupting code sections of a higher execution priority than the first execution priority to pre-empt execution of the first code section for a period of execution to complete each interrupting code section;
• recognizing a first breakpoint in the first code section at the debug controller;
• setting a first halt indication flag as an indication to establish a first debug context;
• halting the processor at the first breakpoint;
• establishing the first debug context;
• clearing the first halt indication flag in response to the establishing of the first debug context;
• allowing the debug controller to process functions of the debug monitor while the processor is halted at the first breakpoint;
• obtaining information representative of the first debug context at the debug monitor, the first debug context associated with register values attributable to the first code section at the first breakpoint;
• receiving an indication that a second code section, of a higher execution priority than the first execution priority, attempts to pre-empt execution of the first code section while the processor is halted at the first breakpoint of the first code section;
• allowing the processor to execute for a period of execution to complete the second code section while maintaining the first debug context of the debug monitor associated with the first breakpoint of the first code section;
• and
• returning control to the debug controller executing the debug monitor in the first debug context upon completion of the second code section.

A computing device comprising:

• a processing unit;
• and
• a debug controller communicatively coupled to the processing unit and including at least one input/output interface,
• wherein the debug controller contains logic that causes the debug controller to perform a debug monitor function, the debug monitor function configured to:
• recognize a first breakpoint for the processing unit in a first code section having a first execution priority, in part, by pausing the processing unit and setting a first halt indication flag as an indication to establish a first debug context;
• establish the first debug context and clear the first halt indication flag;
• receive an indication that a second code section of a higher execution priority than the first execution priority requires servicing while the processing unit is halted at the first breakpoint;
• allow the processing unit to resume execution to service the second code section while maintaining the first debug context and the current state of the first halt indication flag, wherein at least one information access request received via the at least one input/output interface of the debug controller is held while executing the second code section;
• and
• return to an execution state consistent with the first debug context, in part, by pausing the processing unit in the first code section upon completion of servicing the second code section.