Variable tracking word recognizer for detecting the occurrence of a

Abstract

A variable tracking word recognizer generates an indicating signal when a microprocessor has accessed a memory stack location storing a dynamically addressed variable, the address of the variable being the sum of a dynamically assigned base address of the memory stack and a known address offset where the variable is stored on the stack in relation to the base address. The variable tracking word recognizer stores the dynamically assigned base address, when determined by a space allocation subroutine of a program running on the microprocessor, and then monitors the addresses subsequently appearing on the microprocessor address bus, generating the indicating signal when the current address matches the combination of stored base address and known address offset. The variable tracking word recognizer comprises circuitry to generate a storage control signal when the base address appears on the data bus of the microprocessor, a base register for storing the base address on occurrence of the storage control signal, an arithmetic logic unit for determining the difference between the number stored in the base register and each address appearing on the microprocessor address bus, and a conventional word recognizer to generate the indicating signal when the difference so generated equals the known offset.