Lock Linear Region

Locks the specified linear address range.

Call With:

   AX     = 0600H
   BX:CX  = starting linear address of memory to lock
   SI:DI  = size of region to lock (bytes)

Returns:

   if function successful
   Carry flag= clear

   if function unsuccessful
   Carry flag= set
   AX     = error code
           8013H   physical memory unavailable
           8017H   lock count exceeded
           8025H   invalid linear address (unallocated
                   pages)

Notes:

o  If the function returns an error, none of the memory has
   been locked.
o  If the specified region overlaps part of a page at the
   beginning or end of the region, the page(s) will be
   locked.
o  This function may be called more than once for a given
   page; the DPMI host maintains a lock count for each page.
o  This function is ignored by DPMI implementations that do
   not support virtual memory; the function will return the
   Carry flag clear to indicate success, but has no other
   effect.  DPMI hosts which support virtual memory may also
   choose to ignore this function, but such hosts must be
   able to handle page faults transparently at arbitrary
   points during a client's execution, including within
   interrupt and exception handlers.