mtd_cpl question

Matthew Dillon dillon at
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.

					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>

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