Question

3- please convert the following. show all work

a) convert this into one-address machine instruction (load,store,add,sub,mult): E = (A*C) + (B*D)

b) convert this into two-address machine instruction: A= C+B*D*E+A.

c) convert this expression using zero-address machine: a=b-c*d.

Answer 1

(a)Expression:- E= (A*C)+(B*D)

AC is accumulator

M[ ] is memory Location

M[T] is Temporary Location

LOAD	A	AC=M[A]
ADD	B	AC=AC+M[B]
STORE	T	M[T]=AC
LOAD	C	AC=M[C]
ADD	D	AC=AC+M[D]
MUL	T	AC=AC*M[T]
STORE	X	M[X]=AC

(b) Two Address Instruction contains opcode,destination address,source address,mode

A=C+B*D*E+A

R1,R2 are the registers

M[ ] is the memory Location

MOV R1,B R1=M[B]
MOV R2,D R2=M[B]
MUL R1,R2 R1=R1*R2
MOV R2,E R2=M[E]
MUL R1,R2 R1=R1*R2
ADD R1,C R1=R1+C
ADD R1,A R1=R1+A
MOV X,R1 M[X]=R1

(c)

Expression: a=b-c*d
Postfixed : a = BC-D*
TOP means top of stack
M[X] is any memory location

PUSH B TOP=B
PUSH C TOP=C
SUB TOP=B-C
PUSH D TOP=D
MUL TOP=B-C*D
POP X M[X]=TOP