Performance counter for microcode instruction execution and counting method

Abstract

The invention provides a performance counter for microcode instruction execution and a counting method. 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 overhead required to commence measuring microcode execution and to subsequently obtain the measurements are a small number of writes / reads to / from control registers without professional exterior tools or deepening into a detector inside the microprocessor.

Description

technical field [0001] The present invention mainly relates to a microprocessor, in particular to a technique for counting the execution times of microcode instructions in the microprocessor. Background technique [0002] Many modern microprocessors include sequences of microcode instructions, or microcode, that implement complex and / or infrequently executed microprocessor instruction sets. The microcode memory located in the microprocessor contains a plurality of sequences of microcode instructions, and when the microprocessor decodes one of the instructions implemented in microcode in the instruction set, the microprocessor does not send the instruction directly to the microprocessor Instead, control is handed over to the appropriate microcode program in the microcode ROM. Then, the microprocessor sends the microcode instructions to the execution unit for execution to implement the above-mentioned complex and / or rarely executed microcode instructions, so that the executio...

AI Technical Summary

Problems solved by technology

However, since the microcode is directly located in the microprocessor, unlike user-defined program instructions, the acquisition of the microcode cannot be directly observed from the external pins of the microprocessor. Microcode is harder to measure than user-defined programs

Furthermore, although microprocessors usually provide debugging and efficiency measurement functions for user-defined programs (see, for example, Intel 32-bit Processor Architecture Software Developer's Manual Volume 3B: System Programming Guide Part II, 2006 June Edition, Chapter 18), but does not provide the same functionality for microcode use

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