%macro scall 4          
        mov rax,%1  ; func num for o/p data
        mov rdi,%2  ; file descriptor ID for monitor
        mov rsi,%3  ; starting address of string
        mov rdx,%4  ; number of bytes to be displayed
        syscall      ; inbulit func             
%endmacro
section .data         ;initialized variable declaration
	msg1 db "Machine is in Protected Mode"
	msg1len equ $-msg1
	msg2 db "Machine is in Real Mode"
	msg2len equ $-msg2
	msg3 db "Contents of GDTR : "
	msg3len equ $-msg3
	msg4 db "   : "
	msg4len equ $-msg4
	msg5 db "Contents of LDTR : "
	msg5len equ $-msg5
	msg6 db "Contents of IDTR: "
	msg6len equ $-msg6
	msg7 db "Contents of TR: "
	msg7len equ $-msg7
	msg8 db "Contents of MSW/CR0: "
	msg8len equ $-msg8
	
	newline db 10

section .bss   ;uninitialized variable declaration
    var resb 4
    gdtr resq 1
    cnt2 resw 1
    value resb 4
    idtr resb 6
    ldtr resw 1
    tr resb 2
    msw resb 4

section .text
	global _start
	_start:
	smsw eax
	mov[msw], eax
	bt eax,0            ;bt copies bit from register to carry flag (instead of and and cmp)
	;and eax,01h
	;cmp eax,01h
    ;je protected
	jc protected
	scall 1,1,msg2,msg2len
	
protected:
	scall 1,1,msg1,msg1len
	
	scall 1,1,newline,10

	
	SGDT [gdtr]      ;Stores the contents of the global descriptor table register (GDTR) in the destination operand. The destination operand specifies a 8-byte memory location. In ;64-bit mode, the operand size is fixed at 8+2 bytes.The instruction stores an 8-byte base ;and a 2-byte limit
	SIDT [idtr]
	SLDT [ldtr]
	STR [tr]
	;GDTR
	mov bx, word[gdtr + 4]
	scall 1,1,msg3,msg3len
	call HtoA
    mov bx, word[gdtr + 2]
	call HtoA
	mov bx, word[gdtr]
	scall 1,1,msg4,msg4len
	call HtoA
    scall 1,1,newline,10
    
    ;LDTR
    scall 1,1,msg5,msg5len
	mov bx,[ldtr]
	call HtoA
    scall 1,1,newline,10
    
    ;IDTR 
    mov bx, word[idtr + 4]
	scall 1,1,msg6,msg6len
	call HtoA
    mov bx, word[idtr + 2]
	call HtoA
	mov bx, word[idtr]
	scall 1,1,msg4,msg4len
	call HtoA
	scall 1,1,newline,10
	
	;TR
	scall 1,1,msg7,msg7len
	mov bx,[tr]
	call HtoA
	scall 1,1,newline,10
	
	;MSW/CR0
	scall 1,1,msg8,msg8len
	mov bx,[msw + 2]
	call HtoA
	mov bx,[msw]
	call HtoA
	
	mov rax,60
	mov rdi,0
	syscall


;----Procedure-----
HtoA:
    mov rdi,value
    mov byte[cnt2],4H
aup:
    rol bx,04
    mov cl,bl
    and cl,0FH
    cmp cl,09H
    jbe next      ;carry 1 is generated if our digit is 0-9, for that we just need to add 30H 
    add cl,07H
next:
    add cl,30H
    mov byte[rdi],cl
    inc rdi
    dec byte[cnt2]
    jnz aup
    scall 1,1,value,4
ret