| 摘要 |
PURPOSE:To minimize the number of registers which are saved and reset when an interruption is produced by providing a status register where the corresponding bit is set at 1 when the use of this register is detected by a using condition detecting part. CONSTITUTION:When execution of a task is started, a status register 3 is cleared by a microinstruction. Then an instruction is produced. Thus the contents of the register groups other than a general-purpose register group 1 are saved into an external memory. For the register group 1, only the contents of the general-purpose register corresponding to the register 3 are saved. The contents of the register 3 are reset when the interruption processing is through. Then the contents of the general-purpose register 1 corresponding to the bit set at the reset register 3 are reset. In such a way, the time is not required to save and reset a group of registers when an interruption is produced. Thus the overhead is reduced. |
