Central Processing Unit Q.27
- Option : D
- Explanation : Given: A sequence of micro operations
MBR ⇽ PC
MAR ⇽ X
PC ⇽ Y
Memory ⇽ MBR
To find: What these micro operation represents?
Analysis: On conver ting these operations to normal english
1. First micro operation stores the value of PC into memory Base register (MBR)
2. Second micro operation stores value of X into Memory Address register (MAR)
3. Third micro operation stores value of Y into PC
4. Fourth micro operation stores value of MBR to memory.
So before execution of these instructions PC holds the value of next instruction to be executed. We first stores the value of PC to MBR and then through MBR to memory i.e. we are saving the value of PC in memory and then load PC with a new value. This can be done only in two types of operations conditional branch and interrupt service. As we are not checking here for any conditions so it is interrupt service.
