Question

1 . Generate Assembly Codes for the two C programs below

a. Compare the assembly codes generated

b. For code B , analyze and explain how the function call “print_hello()” was materialized inside the computer (compiler, OS and the hardware) for the code B. Use figures and text descriptions if necessary

A)

#include <stdio.h void print hello0; int main(int argc, char *argv[]) print hello0; return 0; void print hello(){ printf("Hello, worldln');

B)

Answer 1

.model small                            ;defines the memory model to be used for the ALP
.data                                   ;data segment begins here
        msg db 10d,13d,"Hello World$"   ;String Hello World gets stored in msg

.code                                   ;code segment begins here
        mov ax,@data                    ;moving base address of data to ax
        mov ds,ax                       ;moving contents of ax into ds
                                        ;data section now gets initialized
        lea dx,msg                      ;load the offset address of msg
        mov ah,09h                      ;to display contents at dx
        int 21h                         ;call the kernel

        mov ah,4ch                      ;to terminate the program
        int 21h                         ;call the kernel
end

32 bit code

section .data                           ;.data starts here
        msg db 10d,"Hello World"        ;String gets initialized
        l equ $-msg                     ;Length Of String
section .text                           ;.text starts here
        global _start                   ;Moving to _start
_start:                                 ;_start label
        mov eax,4                      ;Sys_Write Function
        mov ebx,1                      ;Std_Out File Descriptor
        mov ecx,msg                    ;Offset of msg
        mov edx,l                      ;Length Of msg
        int 80h                                ;Call the Kernel

        mov eax,1                      ;Sys_Exit Function
        mov ebx,0                      ;Sucessful Termination
        int 80h                                ;Call The Kernel
end: