)
Call DPMI mode switch entry point with:
	AX = flags
	    bit 0: set if 32-bit program
	ES = real mode segment of buffer for DPMI private data (ignored if
		SI was zero)
Return: CF set on error
	    program still in real mode
	    AX = error code (DPMI 1.0+)
	       8011h unable to allocate all necessary descriptors
	       8021h 32-bit program specified, but 16-bit DPMI host
	CF clear if successful
	    CS = 16-bit selector corresponding to real-mode CS
	    SS = selector corresponding to real-mode SS (64K limit)
	    DS = selector corresponding to real-mode DS (64K limit)
	    ES = selector to program's PSP (100h byte limit)
	    FS = GS = 0
	    high word of ESP = 0 if 32-bit program
	    program now in protected mode
Note:	this entry point is only called for the initial switch to protected
	  mode