ping22

section .data
msg times 64 db 0
max equ 64

section .text
global _start

_start:
    Read
    mov rdx,max
    mov rsi,msg
    mov rdi,0
    mov rax,0
    syscall

    mov rcx,rax     ; Copy the string for later
    mov rdi,msg     ; Set RDI and RSI to point at message
    mov rsi,msg     ;
    add rdi,rax     ; RDI should point at last character in message
    dec rdi         ;
    shr rax,1       ; Divide length by 2

    .loop           ; Begin loop:
    mov bl,[rsi]    ; Swap the characters using 8 bit registers
    mov bh,[rdi]    ;
    mov [rsi],bh    ;
    mov [rdi],bl    ;
    inc rsi         ; Increment rsi (which is a pointer)
    dec rdi         ; Decrement rdi (also a pointer)
    dec rax         ; Decrement our counter
    jnz .loop       ; If our counter isn't zero, keep looping

    ; Write
    .write
    mov rdx,rcx ; nbytes
    mov rsi,msg ; *msg
    mov rdi,1 ; stream
    mov rax,1 ; syscall
    syscall

    mov rdi, 0
    mov rax, 60
    syscall