How to Write an Assembly Code that Prints Numbers from 1 to 5 Three Times on the Screen

This article explains how to write an assembly code for the x86 architecture that prints the numbers from 1 to 5 three times with each sequence of numbers separated by a new line. The code utilizes the NASM Netwide Assembler and is designed to run on a Linux environment.

Explanation of the Code

The example provided below is an assembly code that achieves the desired functionality:

Assembly Code (NASM Syntax)

section .data    newline db 10, 0          ; New line character     numbers db 1, 2, 3, 4, 5, 0  ; String of numberssection .text    global _start_start:    mov ecx, 3             ; Loop counter for 3 repetitionsprint_numbers:    push ecx              ; Save the loop counter on the stack    mov eax, 4            ; Syscall number for sys_write    mov ebx, 1            ; File descriptor 1: stdout    mov edx, 5            ; Number of bytes to write    lea esi, [numbers]    ; Load address of numbers    int 80h               ; Call kernel    mov edx, 1            ; Number of bytes to write for newline    lea esi, [newline]    ; Load address of newline    int 80h               ; Call kernel    pop ecx               ; Restore loop counter    loop print_numbers    ; Decrement ecx and loop if not zero    mov eax, 1            ; Syscall number for sys_exit    xor ebx, ebx          ; Exit code 0    int 80h               ; Call kernel

Explanation

Data Section

newline db 10, 0 - Contains the newline character (ASCII 10). numbers db 1, 2, 3, 4, 5, 0 - Contains the string representation of the numbers 1 to 5.

Text Section

_start - The entry point of the program. mov ecx, 3 - Initializes the loop counter to 3 for three repetitions. print_numbers - Label marked the beginning of the loop. push ecx - Saves the loop counter on the stack. mov eax, 4 - Calls the Linux syscall for writing (sys_write). mov ebx, 1 - Specifies file descriptor 1 (stdout). mov edx, 5 - Sets the number of bytes to write. lea esi, [numbers] - Loads the address of the numbers array. int 80h - Calls the kernel. mov edx, 1 - Sets the number of bytes to write for a newline. lea esi, [newline] - Loads the address of the newline character. int 80h - Calls the kernel again. pop ecx - Restores the loop counter. loop print_numbers - Decrements the loop counter and loops if it is not zero. mov eax, 1 - Calls the Linux syscall for exiting (sys_exit). xor ebx, ebx - Sets the exit code to 0. int 80h - Calls the kernel to exit the program.

Assembling and Running the Code

To assemble and run this code on a Linux system with NASM installed, follow these commands in the terminal:

nasm -f elf32 -o print_numbers.o print_

ld -m elf_i386 -o print_numbers print_numbers.o

./print_numbers

This will print the numbers from 1 to 5 three times, each sequence on a new line.

Conclusion

By following the provided assembly code and instructions, you can create a program that prints the numbers from 1 to 5 three times with each sequence separated by a new line. This example can be adapted and used in various scenarios to print sequences of numbers or other data in a loop.