Copy variable value and print

;this is completely by me
;if you want to know more, visit
;http://www.oocities.org/codeteacher/x86asm/asml1002.html
;and
;http://www.tutorialspoint.com/assembly_programming/assembly_arithmetic_instructions.htm

section .data           ;initialized variables
    letraA db 'A',0xa   ;our letter and \n
    lenletraA equ $-letraA  ;length in bits

segment .bss            ;uninitialized variables
    letra resw 1    ;reserve memory space for one letter

section .text
    global _start

_start:

    mov ax, [letraA]    ;mov the letter A to ax
    mov [letra], ax     ;mov ax to new variable
    ;we also can use eax, but i use ax because it
    ;use just 16bits and eax use 32
    ;to print without \n you also can use al (8bits)

    mov eax, 4      ;sys_write
    mov ebx, 1      ;stdout
    mov ecx, letra      ;our variable to output
    mov edx, lenletraA  ;length of output
    int 0x80        ;call hernel to print

    mov eax, 1      ;sys_exit
    mov ebx, 0      ;tell the system it's everything ok
    int 0x80        ;call kernel to finisih program