| 摘要 |
PROBLEM TO BE SOLVED: To provide a microprocessor which reduces processes for saving the contents of a general register to a stack of a data memory or reloading them. SOLUTION: From a protection flag indicating whether or not a general register 6 is written, it is judged whether or not an instruction execution result is written to the general register 6. An instruction decoding part 19 outputs a select signal selecting the instruction execution result held in the general register to a multiplexer 15 when the protection flag shows a write request state and outputs the select signal selecting the instruction execution result transferred through a bypass path to the multiplexer 15 when the value of the protection flag indicates a write stop state to pass and receive the instruction execution result, and also stops the writing to the general register 6 by regarding the address of the write destination as the address of a read-only register.
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