compiler Design

Question

Please Answer this question 

4. Discuss design issues in code generation. Generate target code for the following basic block.   

           t1 : = a + b

           t2 : = c + d

           t3 : = e - t2

           t4 : = t1 - t3

 

Answer 1

 

 ⦁ Issues in Code Generation are:

1. Input to code generator

2. Target program

3. Memory management

4. Instruction selection

5. Register allocation

6. Choice of evaluation

7. Approaches to code generation

 

 

Generate target code for the basic block:

Statement	L	Code Generated	Register descriptor	Address descriptor
			All Register empty
t1 : = a + b	R0	MOV a, R0 ADD b, R0	R0 contains t1	T1 in R0
t2 : = c + d	R1	MOV c, R1 ADD d, R1	R1 contains t2	T2 in R2
t3 : = e - t2	R1	SUB e, R1	R1 contains t3	T3 in R1
t4 : = t1 - t3	R0	SUB  R0, R1	R0 contains t4	T4 in R0
		MOV R0, Result		Result in R0 and memory