Abstract: A system is provided that includes an instruction buffer that stores bytes representative of one or more macroinstructions and instruction length decoder circuitry. The instruction length decoder circuitry includes a non-sequential first multiplexer circuitry having first input lines receiving a first input data representative of a speculative length of a first macroinstruction of the macroinstructions, and first selector that selects from the first input lines via a one-hot selector vector. The instruction length decoder circuitry also includes a first output line communicatively coupled to second selector, wherein the first output line causes the selector to select from a second input data representative of a first location of a first ending byte for the first macroinstruction with respect to a value x. The first multiplexer circuitry and the second selector may output start and end byte locations for the macroinstructions.