comparison64Bit.asm

; assembly code when comparison using 64-bit registers

section	.data
   samemsg db "They are the same: ", 10
   samelen equ $- samemsg 
   answer dq 'h' ; correct answer this line changed to have 64 bits
   notsamemsg db "They are not the same: ", 10
   notsamelen equ $- notsamemsg 
segment .bss
   guess resb 1
section	.text
global _start         ;must be declared for using gcc
_start:	                 ;tell linker entry point

mov eax, 3 ; read from keyboard
mov ebx, 2;  
mov ecx, guess ; move guess into ecx
mov edx, 1 ;  As single letter using 1 byte
int 80h	; call interrupt
   mov   rax, [guess] ; move guess by user into rax
   cmp   rax, [answer]  ; compare correct answer with what in rax
   je    same ; if they are the same jump to same
   call notSame ; else jump to notSame
	same:
   mov   ecx,samemsg ; same message
   mov   edx, samelen ; length of same message
   mov   ebx,1	;file descriptor (stdout)
   mov   eax,4	;system call number (sys_write)
   int   0x80	;call kernel 
   mov   eax, 1
   int   80h
notSame: 
   mov   ecx,notsamemsg ; not same message
   mov   edx, notsamelen ; not same message length
   mov   ebx,1	;file descriptor (stdout)
   mov   eax,4	;system call number (sys_write)
   int   0x80	;call kernel 
   mov   eax, 1
   int   80h