Question

Draw the stack (use, word/pdf) before every instruction that is marked red is executed to show your understanding of the call and return functions.   Use N/A to represent unpredictable values.

            
            Main Proc
            4040018          mov ecx, 0000000Ch
            404001C          mov ebx, 0000000Bh
            4040020          call FADD
            4040026          mov eax, ebx
                      …
                      …                    

            Main EndP

            FADD  PROC
            4041040          Push ecx
            4041044          Push ebx
            4041048          mov eax, edx
                      …
                      …
            404A060         Pop ebx
            404A062         Pop ecx
            404A064         ret
            FADD EndP

Answer 1

Answer:

Main Process will start

At instruction 4040018 the ecx variable will be having 0000000Ch as a value

At instruction 404001C the ebx variable will be having 0000000Bh as a value

ecx

0000000Bh

ebx

0000000Ch

At instruction 4040020 the FMul process will be called

The control will be under the FMul process now

At instruction 4041040 the value of variable ecx will be pushed in Stack

At instruction 4041044 the value of variable ebx will be pushed in Stack

At instruction 4041048 the value(N/A) of variable edx will be moved to eax variable

At instruction 404A060 the value of variable ebx will be poped out from Stack

At instruction 404A062 the value of variable ecx will be poped out from Stack

At instruction 404A064 the value of variable ebx and ecx will be returned and provided to the Main Process

Now the control will be under Main Process once the execution of FMul Process is completed

At instruction 4040026 the value of variable ebx will be moved to the variable eax.