; NASM 64 bit X86-64 assembly on Linux

global main
extern printf

segment .data

printffmt db `%ld\n`,0

segment .text

main:	
    push rbp
    mov rbp,rsp

; used rbx and r12 because printf preserves these values

    mov rbx,1024                 ; start with 1024
    mov r12,2                    ; load 2 as divisor

.toploop                         ; top of while loop
    cmp rbx,0                    ; compare to 0
    jle .done                    ; exit 0 or less

    lea rdi,[printffmt]          ; print number in rsi
    mov rsi,rbx                  ; mov to rsi as argument
    call printf

; calculate n/2 and save
    xor rdx,rdx                  ; clear rdx for division
    mov rax,rbx                  ; mov number to rax for division
    idiv r12                     ; divide by 2
    mov rbx,rax                  ; save n/2

    jmp .toploop                 ; next loop

.done
    xor rax,rax                  ; return code 0
    leave                        ; fix stack
    ret                          ; return