| 摘要 |
PURPOSE:To completely check the normality of a shift count by providing a comparing circuit for comparing the contents of a shift count register and a count check register. CONSTITUTION:The count check register 3 can set data 102 for comparing and checking the contents of the shift count register 2 under the instruction of a microprogram and a check mode register 4 instructs a comparing method in the comparison circuit 5 by the register of two bits. When the shift count for shifting by a shifter 1 according to the type of an executed instruction is the value of a previously limited range, a suitable value is set to the count check register 3 and the check mode register 4 according to the microprogram, thereby, an abnormality on a hardware or the microprogram can be understood. Thereby, the normality of the shift count can be effectively checked and an omission in detecting the abnormality of data can be reduced. |
