1. A method for populating a first data structure by using a register template, the method comprising: receiving an incoming instruction sequence using a global front end; grouping instructions from the incoming instruction sequence to form instruction blocks, wherein each instruction block includes a group of instructions; using a register template to track instruction destinations and instruction sources by populating the register template with block numbers corresponding to the instruction blocks, wherein the block numbers corresponding to the instruction blocks indicate interdependencies among the instruction blocks, and wherein an incoming instruction block writes its respective block number into fields of the register template corresponding to destination registers referred to by the incoming instruction block; populating the first data structure, wherein the first data structure stores instructions corresponding to the instruction blocks as recorded by the register template; and using the first data structure to feed instructions to a plurality of stacked execution units of an execution stage of a multistage processor in accordance with a readiness of instruction sources of the instruction blocks.