Renesas Technology Corp.

Tomomi Ishikura

Hiromichi Yamada

Takanaga Yamazaki

Takeshi Kataoka

Yasuo Sugure

Kazuya Hirayanagi

Seiji Takeuchi

The present invention prevents a data processor from undesirable operation stop due to an overflow of a plurality of register banks. A status register includes an overflow flag to indicate an overflow of the plurality of register banks. When an interrupt exception occurs in a state in which data has been saved to all banks of the register banks, and the accepted interrupt exception is permitted to use the register banks, a central processing unit saves data of a register set to a stack area and reflects an overflow state in the overflow flag. When the overflow flag indicates an overflow state, if data restoration from the register banks to the register set is directed, the central processing unit restores the data from the stack area to the register set.

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Kokubunji, Japan

Tomomi Ishikura