NAME
        AllocExpansionMem - allocate expansion memory

   SYNOPSIS
        startSlot = AllocExpansionMem( numSlots, slotOffset )
        D0                             D0        D1

   FUNCTION
        (Not typically called by user code)

        This function allocates numslots of expansion space (each slot
        is E_SLOTSIZE bytes).  It returns the slot number of the
        start of the expansion memory.  The EC_MEMADDR macro may be
        used to convert this to a memory address.

        Boards that fit the expansion architecture have alignment
        rules.  Normally a board must be on a binary boundary of its
        size.  Four and Eight megabyte boards have special rules.
        User defined boards might have other special rules.

        If AllocExpansionMem() succeeds, the startSlot will satisfy
        the following equation:

                (startSlot - slotOffset) MOD slotAlign = 0

   INPUTS
        numSlots - the number of slots required.
        slotOffset - an offset from that boundary for startSlot.

   RESULTS
        startSlot - the slot number that was allocated, or -1 for error.

   EXAMPLES

                AllocExpansionMem( 2, 0 )

        Tries to allocate 2 slots on a two slot boundary.

                AllocExpansionMem( 64, 32 )

        This is the allocation rule for 4 meg boards.  It allocates
        4 megabytes (64 slots) on an odd 2 meg boundary.

   EXCEPTIONS

   SEE ALSO
        freeexpansionmem()

   BUGS