> the easy, obvious and completely bad way...

another bad way:) and untested as well:

/* eventually use:  unsigned char xdata *
 * as return type instead of unsigned int
 */
unsigned int get_eo_xiseg(void) __naked
{
  __asm
        mov     a,#s_XISEG      ; start
        add     a,#l_XISEG      ; length
        mov     dpl,a
        ;
        mov     a,#(s_XISEG>>8) ; start
        addc    a,#(l_XISEG>>8) ; length
        mov     dph,a
        ;
        ret
  __endasm;
}

(Assuming XISEG is the last used xdata segment)

Unfortunatly the linker does not output
a symbol for the end of the segment
(as Russ suggested ) so an addition is
needed.

Greetings,
Frieder