Processor loop buffer

Abstract

A method and apparatus for executing program loops. A processor, includes an execution unit and an instruction fetch buffer. The execution unit is configured to execute instructions. The instruction fetch buffer is configured to store instructions for execution by the execution unit. The instruction fetch buffer includes a loop buffer configured to store instructions of an instruction loop for repeated execution by the execution unit. The loop buffer includes buffer control logic. The buffer control logic includes pointers, and is configured to predecode a loop jump instruction, identify loop start and loop end instructions using the predecoded loop jump instruction and pointers; and to control non-sequential instruction execution of the instruction loop. The width of the pointers is determined by loop buffer length and is less than a width of an address bus for fetching the instructions stored in the loop buffer from an instruction memory.