Circuits and methods are provided for detecting, identifying and/or removing undesired content. According to one embodiment, a method for virus processing content objects is provided. A type associated with a content object is determined. Based on the type, a subset of instructions is read from a virus signature memory containing intermixed op-codes of a first instruction type associated with primitive instructions and of a second instruction type associated with Content Pattern Recognition (CPR) instructions. Then, instructions of the first instruction type are assigned for execution to a primitive instruction pipe of a virus co-processor and instructions of the second instruction type are assigned for execution to a CPR instruction pipe of the virus co-processor. An instruction is executed by the CPR instruction pipe, including accessing a portion of the content object from a system memory and comparing the portion of the content object against a string associated with the instruction.