A method of deterministically generating maximal nonlinear block substitution tables for a predetermined block size is disclosed. The modified diffusion layer will be typically on the cathode side of the fuel cell and its use is to eliminate or minimize flooding of the cathode diffusion layer area, which is a performance limiting condition in direct methanol fuel cells. Instruction-cache in-use indications associated with the instruction-cache lines storing the instructions are updated upon micro-op cache hits. The system exhibits good control over the melt flow index of the copolymer products.