| 摘要 |
PURPOSE:To efficiently execute a program by simplifying an instruction to vary a flag in an assembler program in which branch with a flag condition appears frequently by always performing the decision of a zero flag by a signal from a decoder, and setting a decision result on a flag register. CONSTITUTION:This microcomputer is comprised of a processor unit 10, and main memory 20 connected to the processor unit 10, and it is equipped with an ALU 11, a program counter 12, an A register 13, an instruction decoder 14, the flag registers 15, 16, and a decision circuit 17. When an instruction to always instruct decision on a status flag, for example, the zero flag is executed in the program, such execution is detected by the decoder 14, and hereinafter, the decision on the zero flag is always performed at the decision circuit 17 by the signal from the decoder 14 until the instruction of such decision is cancelled. The decision result is set on the zero flag register 16a of the flag register 16. |
