bigbrain

.section .text
.global main
.intel_syntax noprefix

convert:
  push rbp
  mov rbp, rsp
  sub rsp, 16

  lea rdi, qword ptr [rip+.fmt_scanf]
  lea rsi, qword ptr [rip+input]
  xor rax, rax
  call scanf@plt

  lea rdi, qword ptr [rip+.fmt_printf_message]
  xor rax, rax
  call printf@plt

  # copy 'n' to rdx
  mov r13, [rip+input]

  // bool display = false;
  mov r14, 0

  // int i = 63
  mov r12, 63
  .loop:
    // int bit = r13;
    mov rsi, r13

    // bit = (bit >> i) & 1;
    mov rcx, r12
    shr rsi, cl
    and rsi, 1

    // if (bit)
    cmp rsi, 1
    je .set_display_to_true
    jne .check_if_display

    // display = true
    .set_display_to_true:
      mov r14, 1

    // if (display)
    .check_if_display:
      cmp r14, 1
      jne .decrement

    // printf("%d", bit)
    .show_bit:
      lea rdi, qword ptr [rip+.fmt_printf]
      xor rax, rax
      call printf@plt

    .decrement:
      // i--
      sub r12, 1

    // i >= 0
    cmp r12, 0
    jge .loop

  lea rdi, qword ptr [rip+.newline]
  xor rax, rax
  call printf@plt

  add rsp, 16
  pop rbp

  ret

main:
  push rbp
  mov rbp, rsp
  sub rsp, 16

  .conversion:
    call convert
  jmp .conversion

  add rsp, 16
  pop rbp

  # return 0
  xor rax, rax
  ret

.section .rodata
.fmt_scanf:
  .asciz "%llu"

.fmt_printf_message:
  .asciz "Binary: "

.fmt_printf:
  .asciz "%d"

.newline:
  .asciz "\n"

.section .bss
input: .zero 8