directiveArg :: Parser Expr
directiveArg = try mathExpr
            <|> asmstring
            <|> parens directiveArg
directiveArg :: Parser Expr
directiveArg = try mathExpr
            <|> asmstring
            <|> parens directiveArg
directiveArg = try mathExpr
            <|> asmstring
            <|> parens directiveArg