| 摘要 |
PURPOSE:To make branch forecasting successful by providing an instruction for loading an address whose branch destination is forecast, on a branch forecasting table. CONSTITUTION:By a loading instruction by Ao, a return destination address (address of A3) of a main program is loaded in a register R1. A branch destination address loading instruction LBR generates a branch instruction address by adding the present instruction address (address by A1) and an immediate address I1, and loads the contents of the register R1 as a branch destination address, to a branch forecasting table. The immediate address I1 of the branch destination address loading instruction LBR sets a value which becomes an address of a branch instruction BCR by adding an a address of the instruction LBR. Therefore, the result of retrieval by the branch forecasting table, which is executed at the same time as read-out of an instruction word by A2 coincides with a return address (the contents of R1) of the branch instruction BCR, and consequently, the retrieval is successful.
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