SQL & PL/SQL

i want to update the table by using a decrementor and row id as below.
my_line_count := 0;
select count(*) into my_line_count from emp where empno = in_empno
For line_rec in ( select rowid from emp where empno = in_empno order by countline desc)
loop
update emp set countline = my_line_count where ROWID = line_rec.ROWID;
my_line_count = my_line_count -1;
end loop;
This procedure will be called for suppose 314 times, by another procedure( based on count in emp table i:e for each row);

Before data is like
select countline from emp where empno = in_empno ;
countline
1
1
1
1
1
-- so on

Expected result
select countline from emp where empno = in_empno ; (For exapmle there are 314 rows)
countline
314
313
312
311
.
.
.
3
2
1

Is there any way to perform above logic without loop?