Have you founded yet? testTask: jz

testTask:
jz      skipTask
mov     di, offset postTaskReturn
mov     ax, cs:[bx]
inc     bx
inc     bx
mov     cx, ax
or      al, al
jz      postNoTestPoint
mov     cx, dx
mov     dx, cs:_diagnostic_port
out     dx, al          ; manufacture's diagnostic checkpoint
mov     dx, cx
mov     cx, ax          ;
jmp     $+3             ;
postNoTestPoint:
jmp     $+3             ;
jmp     $+3             ;
jmp     postDispatch