. a) It is a common practice to use a symbolic representation of machine instructions to write a 2+2+3+8 machine-language program. Consider the following high-level language instruction: (A + BXC) D-EXF x (G++/ ) What are the common sources of these operands? What are the basic elements of a machine instruction? Draw an instruction cycle state diagram showing all the steps involved in instruction execution i. ii. iii. iv. Write two separate programs using two- and one-address machine instruction formats respectively to compute the above expression. Values of given operands should not be changed during execution. b) A procedure is the most significant invention in the evolution of programming languages. It is an independent computer program that is embedded within a bigger program. The procedure may be invoked or called at any time within the program. An example program where procedures are called multiple times during its execution is illustrated in Figure 1. Main memory X = i. ii. Addresses 4000 4100 4101 4500 4600 4601 4650 4651 4800 CALL Procl CALL Proc2 CALL Proc2 RETURN RETURN Main program Procedure Procl Procedure Proc2 (CO2) (POI) 5+5 (CO3) (PO2) Figure 1: A program with procedure calls. Draw an execution sequence diagram illustrating how the procedures are called at different addresses during program execution. Based on the given scenario, demonstrate how a processor employs a stack data structure to store return addresses and implement nested procedure calls.