Branching prediction system using branching history table

Abstract

Abstract PURPOSE:To efficiently predict a branching destination address by controlling the effectiveness of the hit of a branching history table in accordance with the changing history of a past branching destination address. CONSTITUTION:At the time of registration, a branching instruction destination address is set in an instruction address register 1, a branching destination changing history table 4 is read, and the changing history of the branching destination address prior by one is read. Information whether or not the branching destination is changed at this time is written in a signal line 105, the address of the branching instruction, which an instruction address register 1 shows is written in a branching instruction address storage 2, and the changing history of the branching destination addresses till this time is written in the branching destination history table 4. At the time of index, the branching instruction address storage 2 is checked based on an instruction taking-out address. When coincident address exists, a signal line 115 goes to '1'. When the branching destination changing history table 4 is checked and the changing history of the past branching destination address is checked. When it is effective, a signal line 109 goes to '1' and a branching destination flag 8 is raised.

Inventors

• 👤 Takeshi Morisada
• 👤 森定　剛
• 👤 Hideshi Ishii
• 👤 石井　英志

Bibliographic Details