Question 1

a) Every assembly language statement will be translated to the respective RTL statements for an instruction cycle with fetch-execute phases. Which phase has the same steps for all assembly language statements and which has various steps depending the statement nature?

b) According to the format specified in Unit 2, write down the RTL steps for the STO instruction of LMC and specify part belongs to fetch phase and which belongs to execute phase.

d) What type of action in a program requires the usage of stack instructions? Explain the function of the stack in such action.

c) Given the following LMC assembly program: 00 LDA 90; 01 ADD 91; 02 OUT; 03 COB; 90 DAT 11; 91 DAT 12; Write the RTL statements for the first two assembly statements in the program and state the contents of PC, IR, ACC, MAR and MDR after executing the RTL statement. (8 marks) First Statement Second Statement