mtd_cpl question
Matthew Dillon
dillon at apollo.backplane.com
Tue May 24 16:10:22 PDT 2005
:
:sys/i386/include/thread.h defines a structure md_thread which contains
:a variable called mtd_cpl that I think is a mask of the current
:software and hardware interrupts. Is the size of this variable tied to
:some x86 architecture constraint or can it be arbitrarily increased to
:something bigger? For instance
:
: unsigned int mtd_cpl[8];
:
:so that the mask can represent all 256 vectors defined in IA.
:
:--
:Chuck Tuffli
:Agilent Technologies
It's constrained to 32 bits at the moment, because all the
interrupt handling assembly uses a bit-test-and-set (btsl)
and bit-test-and-reset (btrl) to mess with it.
The cpl will be going away soon anyway. It's part of the
whole spl system and the spl system is going away. I'm
working on fixing the various subsystems that depend on
e.g. splimp(), and other places... they will all be
replaced by critical sections and other mechanisms.
-Matt
Matthew Dillon
<dillon at xxxxxxxxxxxxx>
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