subject : computer architecture.

(a) The following arithmetic expression has to be evaluated. H[D-(B+C)]/[(E*F)-G] Assume that you cannot use B, C, D, E, F, G for storing the results of an instruction. You can use temporary registers R1, R2. Write an assembly language program for a hypothetical computer using (1) Three-address instructions (ii) One-address instructions (iii) Zero-address instructions (3 marks) The instructions available for use are as follows: Three address One address LOAD X ADD X Y Z STORE X SUB X Y Z ADD X MUL X,Y,Z SUBX DIV XYZ MUL X DIVX Symbolic Representation and interpretation for n-address instructions are given below. Number of Addresses Symbolic Representation Interpretation 3 OP A.B.C A - B OPC 2 , A- A OP B 1 AC ACOPA T - (T-1) OPT OP AC = accumulator T =top of stack (T-1) = second element of stack A.B.C = memory or register locations Continued