PROCESSING DEVICE OF REGISTER WINDOW OVERFLOW/UNDERFLOW

摘要

PURPOSE: A register window overflow/underflow processing apparatus is provided to improve program execution performance of a reduced instruction set computer (RISC) processor, by processing overflow and/or underflow as hardware in the RISC processor having a register window structure. CONSTITUTION: A register window (20) includes local registers and incoming registers, and internal only memories (23,24) store content of the local and incoming register in word unit. A dedicated data bus (25) connects the local and incoming register and the internal only memory. A memory word counter (26) counts storage space of the word unit remaining in the internal only memory. If window overflow or underflow is generated, a logic block controls operation of the dedicated data bus.