1. When a new instruction is loaded into the IR, the PC is loaded with the starting address of the microprogram for that instruction.
2. When a branch microinstruction is encountered, and the branch condition is satisfied, the PC is loaded with the branch address.

Let us examine the contents of microprogram memory and how the microprogram of each instruction is stored or organized in microprogram memory. Consider the two example that are used in our previous lecture . First example is the control sequence for execution of the instruction "Add contents of memory location addressed in memory direct mode to register R1".