| 摘要 |
PURPOSE:To reduce the quantity of hardware by checking whether a branching source address and a branched address are included within previously set upper and lower limit addresses by an existing arithmetic circuit. CONSTITUTION:The upper and lower limit addressed of the branching source address and the branched address are stored in an LS area 51 of a main storage in addition to a pointer and a byte counter. When a branching condition is formed and branching is executed, the branching source address and the branched address are set up on one input of the arithmetic circuit (ALU) 1 and the upper and lower limit addresses stored in the specific area are extracted and set up to the other input to execute four operations. A carry/output zero detecting circuit 9 inputs a carry output to be '1' when the calculated result of the ALU 1 is a negative value and a zero output to be '1' when the calculated result is zero to test the input.
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