section .data
	msg1 db 0xa, 0xb, "enter a Digit (0-9): " ; Message asking for input
	msg2 db 0xa, 0xb, "squared number is: "  ; Message to show squared result
	msg3 db 0xa, 0xb, "Enter between 0 - 9 " ; Error message if input is out of range

section .bss
	inbuf resb 1      ; Buffer for storing single character input
	outbuf resb 2     ; Buffer for storing 2 characters output (square result)

section .text
global _start

_start:

; Print the input prompt message
mov edx, 23         ; Length of msg1
mov ecx, msg1       ; Point to msg1
mov ebx, 1          ; File descriptor (1 = stdout)
mov eax, 4          ; sys_write system call
int 0x80            ; Call kernel

; Read a single character from stdin
mov ebx, 0          ; File descriptor (0 = stdin)
mov ecx, inbuf      ; Buffer to store the input
mov edx, 1          ; Number of bytes to read
mov eax, 3          ; sys_read system call
int 0x80            ; Call kernel

; Validate if input is between '0' and '9'
mov al, byte[inbuf] ; Load input character into AL
cmp al, '0'         ; Check if input is less than '0'
jl ERRORMSG         ; Jump to error if less than '0'
cmp al, '9'         ; Check if input is greater than '9'
jg ERRORMSG         ; Jump to error if greater than '9'

; Print the entered value
mov edx, 1          ; Length of inbuf
mov ecx, inbuf      ; Point to inbuf
mov ebx, 1          ; File descriptor (stdout)
mov eax, 4          ; sys_write
int 0x80            ; Call kernel to print input character

; Convert ASCII character to numerical value
mov al, byte[inbuf] ; Load character again
sub al, '0'         ; Convert ASCII to integer (0-9)

; Square the number (AL * AL)
mul al              ; Multiply AL by itself, result is in AX (AL * AL)

; Split result into tens and units
mov bl, 10          ; Divisor for decimal conversion
div bl              ; Divide AX by 10: AL = quotient, AH = remainder
add al, '0'         ; Convert quotient to ASCII
add ah, '0'         ; Convert remainder to ASCII
mov word[outbuf], ax ; Store the two ASCII characters in outbuf

; Print the output message for the squared number
mov edx, 21         ; Length of msg2
mov ecx, msg2       ; Point to msg2
mov ebx, 1          ; File descriptor (stdout)
mov eax, 4          ; sys_write
int 0x80            ; Call kernel

; Print the squared number
mov edx, 2          ; Length of outbuf
mov ecx, outbuf     ; Point to outbuf
mov ebx, 1          ; File descriptor (stdout)
mov eax, 4          ; sys_write
int 0x80            ; Call kernel

; Exit the program
mov eax, 1          ; sys_exit
mov ebx, 0          ; Exit code 0
int 0x80            ; Call kernel

ERRORMSG:
; Display error message if input is not in range
	mov edx, 21         ; Length of msg3
	mov ecx, msg3       ; Point to msg3
	mov ebx, 1          ; File descriptor (stdout)
	mov eax, 4          ; sys_write
	int 0x80            ; Call kernel
	jmp ENDPROG         ; Jump to program end

ENDPROG:
; Exit program
	mov eax, 1          ; sys_exit
	mov ebx, 5          ; Exit code 5 (error)
	int 0x80            ; Call kernel