signature C_CALL = sig

  structure T : MLTREE

  (* multiple calling conventions on a single architecture *)
(*  type calling_convention *)

  (* prototype describing C function *)
  type  c_proto = 
    { (* conv : calling_convention, *)
      retTy : CTypes.c_type,
      paramTys : CTypes.c_type list
     }

  exception ArgParamMismatch

  datatype  c_arg 
    = ARG of T.rexp	
	(* rexp specifies integer or pointer; if the 
         * corresponding parameter is a C struct, then 
	 * this argument is the address of the struct. 
	 *)
    | FARG of T.fexp
	(* fexp specifies floating-point argument *)
    | ARGS of c_arg list
	(* list of arguments corresponding to  contents of a C struct *)

  (* translate a C function call with the given argument list into
   * a MLRISC statement list.  The structRet function is called
   * to allocate space for returning a C struct.  The result of
   * genCall is a mlrisc list specifying where the result is and the
   * MLRisc statements that implement the calling sequence.  Functions
   * with void return type have no result, most others have one result,
   * but some conventions may flatten larger arguments into multiple
   * registers (e.g., a register pair for long long results).
   *)
  val genCall :
      { name  : T.rexp,
        proto : c_proto,
        structRet :  {szb : int, align : int} -> T.rexp,
        args : c_arg list
       }
      ->
      { callseq : T.stm list,
        result: T.mlrisc list
       }
end