> Actually, that isn't quite true. RF is always set when we get the
> page fault. It turns out there's no way to distinguish a real trace
> trap from an INT 1 or ICEBP/INT01, and that full decoding of the BOUND
> instruction is not necessary because the saved PC points to the BOUND
> instruction itself. Incorporating only these two changes, the
> processing rules I suggested would be more correctly stated as:
I disagree with the above statement. According to my note regarding INT1,
you can always get the INT1 status by DR6 debug register. The following is
the list of the meaning when these bits are set in DR6 (the note is for 386,
but I think it applies to later chips).
Bits - Reason
------------------------------------------------------
B0 - Breakpoint defined by DR0 is triggered.
B1 - Breakpoint defined by DR1 is triggered.
B2 - ...... by DR2 is triggered.
B3 - ...... by DR3 is triggered.
BD - Intel ICE hardware is active and ICE is blocking the use of debug
registers.
BS - Single step (TF is set)
BT - Task switch (T bit in TSS is set).
This is what the bits look like:
_________________________________________________________________
| |B|B|B| |B|B|B|B|
| 0 |T|S|D| 0 |3|2|1|0| DR6
-----------------------------------------------------------------
31 16 0
--Robin Hood Liu Li-Kai, Edwin
ICQ UIN: 1311717 (dolphin)
mailto:robin.hood@ibm.net -----------------------------------
Golden Rules for Living
- If you open it, close it. - If you turn it on, turn it off. - If you unlock it, lock it up. - If you break it, admit it. - If you can't fix it, call in someone who can. - If you borrow it, return it. - If you value it, take care of it. - If you make a mess clean it up. - If you move it, put it back. - If it belongs to someone else and you want to use, get permission. - If you don't know how to operate it, leave it alone. - If it's none of your business, don't ask questions. - If it ain't broke, don't fix it. - If it will brighten someone's day, say it. - If it will tarnish someone's reputation, keep it to yourself.
By Source Unknown from Condensed Chicken Soup for the Soul Copyright 1996 by Jack Canfield, Mark Victor Hansen & Patty Hansen