Execution of a full Instruction:

Regard as the instruction:

Add (R3), R1

• Executing this particular instruction needed the below described actions:

a) Fetch the instruction

b) Fetch the primary operand (the contents of the memory location pointed to by R3)

c) Perform the addition operation

d) Load the result into R1register

Control Sequence for instruction Add (R3), R1:

• PCout, MARin, Read, Select4, Add, Zin
• Zout, PCin, Yin, Wait for the MFC
• MDRout, IRin
• R3out, MARin, Read
• R1out, Yin, Wait for MFC
• MDRout, Select Y, Add, Zin
• Zout, R1in, End

Branch Instructions:

• PCout, MARin, Read, Select4, Add, Zin
• Zout, PCin, Yin, Wait for the MFC (WFMC)
• MDRout, Irin
• offset_field_of_IRout, Add, Zin
• Zout, PCin, End