option casemap:none

ifndef __SOMECLASS_CLASS__
__SOMECLASS_CLASS__   equ 1

  ;; Once again, HeapAlloc/Free is REQUIRED by the class extention for windows.
  ;; Malloc/Free are used by Linux and OSX. So the function prototypes have to
  ;; be defined somewhere. If you have include files where they're defined, just
  ;; include them in the usual way and remove the option dllimports.
  if @Platform eq 1             ;; Windows 64
    ;; include windows.inc
    ;; includelib kernel32.lib
    option dllimport:<kernel32>
      HeapAlloc       proto :qword, :dword, :qword
      HeapFree        proto :qword, :dword, :qword
      ExitProcess     proto :dword
      GetProcessHeap  proto
    option dllimport:none
      exit            equ ExitProcess
  elseif @Platform eq 3         ;; Linux 64
    ;;include libc.inc
    malloc            proto SYSTEMV :qword
    free              proto SYSTEMV :qword
    exit              proto SYSTEMV :dword
  endif

  printf              proto :qword, :VARARG

  CLASS someClass
    CMETHOD someMethod
  ENDMETHODS
    var dd ?
  ENDCLASS

  ;; The OS' ABI has an effect on this class extention. That is, the class self pointetr
  ;; is usually refferenced in the first arg register. So for Windows it would be rcx and
  ;; Linux would be rdi. So to write code that will assemble on both we use a register
  ;; that ISN'T used to pass arguments in either ABI(Not sure about OSX's ABI however)
  METHOD someClass, Init, <VOIDARG>, <>, a:dword
    mov rbx, thisPtr
    assume rbx:ptr someClass
    mov [rbx].var, a
    mov rax, rbx
    assume rbx:nothing
    ret
  ENDMETHOD

  METHOD someClass, someMethod, <dword>, <>
    mov rbx, thisPtr
    assume rbx:ptr someClass
    mov eax, [rbx].var
    assume rbx:nothing
    ret
  ENDMETHOD

  METHOD someClass, Destroy, <VOIDARG>, <>
    ret
  ENDMETHOD
endif                         ;; __CLASS_CLASS_

.code
main proc
  local meh:ptr someClass
  ;; Create a new instance of someClass with an arg of 7
  mov meh, _NEW(someClass, 7)
  meh->someMethod()              ;;Get meh->var value and return it in RAX
  invoke printf, CSTR("class->someMethod = %i",10), rax
  _DELETE(meh)                   ;; DIIIIIIIE!
  invoke exit, 0                 ;; Crashy crashy without it.
  ret
main endp

end