The cdecl calling convention is the standard convention in C and C++ high-level languages. Parameters are stored on a stack with the rightmost parameter pushed onto stack first and the leftmost parameter pushed onto stack last. It is the caller's responsibility to restore the stack once it regains control.

The simplest macro that emulates the cdecl procedure invocation would be as follows:

macro ccall procName, [args]
{
   common
   a = 0
   if ~args eq
      forward
      a = a + 4
      reverse 
      push args
   end if
   common
   call procName
   if a > 0
      add  esp, a
   end if
}

The if clauses here are self-explanatory; however, you may simply ignore them for now as they will be covered a bit later in this chapter.