Abstract: A multi-core microprocessor includes first and second processing cores and a bus coupling the first and second processing cores. The bus conveys messages between the first and second processing cores. The cores are configured such that: the first core stops executing user instructions and interrupts the second core via the bus, in response to detecting a predetermined event; the second core stops executing user instructions, in response to being interrupted by the first core; each core outputs its state after it stops executing user instructions; and each core waits to begin fetching and executing user instructions until it receives a notification from the other core via the bus that the other core is ready to begin fetching and executing user instructions. In one embodiment, the predetermined event comprises detecting that the first core has retired a predetermined number of instructions. In one embodiment, microcode waits for the notification.

Abstract: A microprocessor integrated circuit includes first and second processors. The first processor is configured to detect that the second processor has not retired an instruction for a predetermined amount of clock cycles and to responsively reset the second processor. The microprocessor integrated circuit also includes microcode. The second processor is configured to execute the microcode in response to a reset of the second processor. The microcode is configured to read debug information within the microprocessor integrated circuit and to output the debug information external to the microprocessor integrated circuit in response to determining that the reset was performed by the first processor.

Abstract: A microprocessor integrated circuit includes first and second processors, an internal memory accessible by the first and second processors, and a bus interface unit configured to interface to a bus external to the microprocessor for providing access to a memory external to the microprocessor. The bus interface unit, external bus, and external memory are accessible by the second processor but are inaccessible by the first processor. The first processor writes debug information to the internal memory. The first processor detects an event and provides a notification of the event to the second processor. The second processor, coupled to the bus interface unit, executes microcode in response to the event notification received from the first processor. The microcode reads the debug information from the internal memory and writes the debug information to the external memory via the bus interface unit and external bus for use in debugging the second processor.

Abstract: A multi-core microprocessor includes first and second processing cores and a bus coupling the first and second processing cores. The bus conveys messages between the first and second processing cores. The cores are configured such that: the first core stops executing user instructions and interrupts the second core via the bus, in response to detecting a predetermined event; the second core stops executing user instructions, in response to being interrupted by the first core; each core outputs its state after it stops executing user instructions; and each core waits to begin fetching and executing user instructions until it receives a notification from the other core via the bus that the other core is ready to begin fetching and executing user instructions. In one embodiment, the predetermined event comprises detecting that the first core has retired a predetermined number of instructions. In one embodiment, microcode waits for the notification.

Abstract: A microprocessor integrated circuit includes first and second processors, an internal memory accessible by the first and second processors, and a bus interface unit configured to interface to a bus external to the microprocessor for providing access to a memory external to the microprocessor. The bus interface unit, external bus, and external memory are accessible by the second processor but are inaccessible by the first processor. The first processor writes debug information to the internal memory. The first processor detects an event and provides a notification of the event to the second processor. The second processor, coupled to the bus interface unit, executes microcode in response to the event notification received from the first processor. The microcode reads the debug information from the internal memory and writes the debug information to the external memory via the bus interface unit and external bus for use in debugging the second processor.

Abstract: A microprocessor integrated circuit includes first and second processors. The first processor is configured to detect that the second processor has not retired an instruction for a predetermined amount of clock cycles and to responsively reset the second processor. The microprocessor integrated circuit also includes microcode. The second processor is configured to execute the microcode in response to a reset of the second processor. The microcode is configured to read debug information within the microprocessor integrated circuit and to output the debug information external to the microprocessor integrated circuit in response to determining that the reset was performed by the first processor.

Abstract: An apparatus for counting microcode instruction execution in a microprocessor includes a first register, a second register, a comparator, and a counter. The first register stores an address of a microcode instruction. The microcode instruction is stored in a microcode memory of the microprocessor. The second register stores an address of the next microcode instruction to be retired by a retire unit of the microprocessor. The comparator compares the addresses stored in the first and second registers to indicate a match between them. The counter counts the number of times the comparator indicates a match between the addresses stored in the first register and the second register. The first register is user-programmable and the counter is user-readable. A mask register may be included to create a range of microcode memory addresses so that executions of microcode instructions within the range are counted.