Generating design structure for microprocessor with arithmetic logic units and an efficiency logic unit

A method in a computer-aided design system for generating a functional design model of a processor, said method comprising:

• generating a functional representation of an efficiency logic unit in the processor to receive an instruction and determine whether the instruction is an updating fixed point instruction or a non-updating fixed point instruction based on a number of general registers to be used to execute the instruction;
• wherein the efficiency logic is to compare the instruction to a predetermined list or table of instructions that indicates that a first arithmetic logic unit (ALU) or a second ALU executes each of the instructions;
• and
• generating a functional representation of the first ALU coupled to the efficiency logic unit and the first ALU coupled to the general registers in the processor to read data from the general registers and write data to the general registers, wherein the efficiency logic unit is to receive and execute the instruction, and, if the instruction is the updating fixed point instruction, store an update value in a general register coupled to the first ALU;
• and
• generating a functional representation of the second ALU, the efficiency logic unit and the second ALU coupled to the general registers in the processor to only read data from a general register file and the efficiency logic unit to receive and fully execute the instruction only if the instruction is the non-updating fixed point instruction, wherein the non-updating fixed point instruction belongs to a set of non-updating fixed point instructions comprising an arithmetic operation.