1 Code Generation Code generator phase ... - VTU e-Learning

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eturn Three address code that will be generated for the above set of statements is as follows. 10: action 1 20: MOV # 40, 200 /* Save return address 40 at location 200 */ 30: GOTO 100 40: Action 2 50: end /* code for function */ 100: action 3 100: GOTO * 200 200: 40(return address) Stack allocation: Whenever the function is called the activation record of called fun c is stored on Stack, once the function returns, it is removed from Stack. Final code that will be generated for stack area for initialize the Stack is MOV # Stack.begin, SP /* initialize the Stack Pointer */ SP denotes Stack Pointer. <strong>Code</strong> for Call statement is as follows Add # main.record size, SP /*main.recordsize referes to record size of caller function*/ MOV # current +16, *SP /*Save return address*/ GOTO function.code_area Return statement has the following target code. GOTO *0(SP) SUB # main.recordsize, SP Example: For the below three address code /* code for a */ action1 call c action 2 end 6
* code for b */ action 3 return /* code for c */ action 4 call b action 5 call c action 6 call c return The final code generated will be as follows: /* code for a * / 100: MOV # 600, SP // initialize stack 110: action 1 120: ADD # a.size, SP 130: MOV # 150, * SP 140: GOTO 300 150: SUB # a_size, SP 160: action 2 170: end /* code for b */ 200: action 3 210: GOTO * 0(SP) /* code for c */ 300: action 4 310: ADD # c_size, SP 7
Page 1 and 2: Code Generation Code generator phas
Page 3 and 4: d. Index addressing mode- this is o
Page 5: 1. Call. 2. Return 3. end 4. action
Page 9 and 10: Code Optimization has to mainly ach
Page 11 and 12: In order to generate more optimized
Page 13 and 14: Each instruction takes some machine
Page 15 and 16: 6 H go to 13 B6 7 8 9 10 11 12 13 1
Page 17 and 18: Fig 9.4 DAG for the three address c
Page 19: After topological sorting t2 = b -

1 Code Generation Code generator phase ... - VTU e-Learning

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