SQL & PL/SQL

When we explicitly RAISE an error, it looks like the CALL STACK is removed from the errror message. Why does that happen? Here's a simple example of what I'm seeing:

SQL> create or replace procedure proc2 
  2  is
  3    v number;
  4  begin
  5    v := 1/0;
  6  end;
  7  /

Procedure created.

SQL> create or replace procedure proc1
  2  is
  3  begin
  4    proc2();
  5  end;
  6  /

Procedure created.

SQL> exec proc1();
BEGIN proc1(); END;

*
ERROR at line 1:
ORA-01476: divisor is equal to zero
ORA-06512: at "XRFOR.PROC2", line 5
ORA-06512: at "XRFOR.PROC1", line 4
ORA-06512: at line 1

This is what I like. I can see that the error occured in PROC2 in this case. But if I put an EXCEPTION HANDLER in PROC1, I lose that information:

SQL> create or replace procedure proc1
  2  is
  3  begin
  4    proc2();
  5  exception when others then
  6    raise;
  7  end;
  8  /

Procedure created.

SQL> exec proc1();
BEGIN proc1(); END;

*
ERROR at line 1:
ORA-01476: divisor is equal to zero
ORA-06512: at "XRFOR.PROC1", line 6
ORA-06512: at line 1

I'm left erroneously thinking that the error came out of PROC1. I'm not sure why, but I've never noticed this before. How do I intervene in an EXCEPTION HANDLER (to write the error to a log) without losing the contents of the stack in the error message?

Thanks,
--=Chuck