.text
        .global _start
_start:
        movl    $3, %eax
        movl    $0, %ebx
        movl    %esp, %ecx
        movl    $1, %edx
        int     $0x80
        test    %eax, %eax
        jle     end
        movzb   (%esp), %eax
        sub     $'a', %eax
        cmp     $25, %eax
        ja      need_no_change
        sub     $'A', %eax
        movb    %eax, (%esp)
need_no_change:
        movl    $4, %eax
        movl    $1, %ebx
        movl    %esp, %ecx
        movl    $1, %edx
        int     $0x80
        call    _start
end:
        movl    $1, %eax
        xorl    %ebx, %ebx
        int     $0x80