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Added musings about where to deal with debug registers.

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git-svn-id: file:///srv/svn/repos/haiku/trunk/current@11506 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Ingo Weinhold 2005-02-28 00:42:01 +00:00
parent d906f5fc4b
commit 336b15cf0f
1 changed files with 12 additions and 0 deletions
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12
src/kernel/core/arch/x86/arch_int.c
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@ -306,6 +306,18 @@ i386_handle_trap(struct iframe frame)
if (thread)
i386_pop_iframe(thread);
// ToDo: Somewhere around here (maybe in int_bottom), we need to update some of
// the debug registers, if the thread is a userland thread.
// * (t_to->debug_info.flags & B_THREAD_DEBUG_SINGLE_STEP) indicates whether we
// shall set the TF flags in EFLAGS. We probably best manipulate the
// value on the stack, so that the flag is set by iret and applies to the
// next userland instruction first.
// * Break- and watchpoints are probably best dealt with in
// arch_thread_context_switch(). At least DR0-DR3 should be set there.
// DR7 (the debug control register) is better updated here.
// * int_bottom should always disable break- and watchpoints (by setting
// DR7 accordingly).
}