NAME
        CacheControl - Instruction & data cache control

   SYNOPSIS
        oldBits = CacheControl(cacheBits,cacheMask)
        D0                     D0        D1

        ULONG CacheControl(ULONG,ULONG);

   FUNCTION
        This function provides global control of any instruction or data
        caches that may be connected to the system.  All settings are
        global -- per task control is not provided.

        The action taken by this function will depend on the type of
        CPU installed.  This function may be patched to support external
        caches, or different cache architectures.  In all cases the function
        will attempt to best emulate the provided settings.  Use of this
        function may save state specific to the caches involved.

        The list of supported settings is provided in the exec/execbase.i
        include file.  The bits currently defined map directly to the Motorola
        68030 CPU CACR register.  Alternate cache solutions may patch into
        the Exec cache functions.  Where possible, bits will be interpreted to
        have the same meaning on the installed cache.

   INPUTS
        cacheBits - new values for the bits specified in cacheMask.

        cacheMask - a mask with ones for all bits to be changed.

   RESULT
        oldBits   - the complete prior values for all settings.

   NOTE
        As a side effect, this function clears all caches.

   SEE ALSO
        exec/execbase.i, cacheclearu(), cachecleare()