| 摘要 |
PURPOSE:To quickly process the instruction following a branch instruction by preventing the execution of the instructions prefetched after the branching instruction when a branching predictive failure signal is outputted and prefetching the instructions following the branching instruction in the correct branching direction via an advancing control circuit. CONSTITUTION:An input indicator 1 is set by the operand input data and held in an executing cycle. A through register 2 holds only '1' as an executing cycle as long as the arithmetic result is equal to the operand input data. Then a branching predictive register 3 holds the branching instruction at '1' if it is decided that the advancing control circuit prefetches the instruction following the branching instruction from the branch side and then at '0' as long as said instruction is not prefetched. A type register 4 holds the type of the branching instruction and a branching predictive failure detecting circuit 5 decides the branch or non-branch between both registers 2 and 4 during a data transfer cycle. The result of said decision is compared with the output of the register 3 and this discordant result is outputted through the circuit 5.
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