User's Manual

80286 SYSTEM INITIALIZATION
Telt Ihe ~elcrlptor lable Ilze In AX 10 yerlfy Ihat It II an
even number of delcrlptor! In [englh.
tel t_dt_Ilml I proc
pUlh
ax
Save lenglh
and
01·,7
Look a I low
order bit!
cmp
a 1,7
MUlt be all one!
pop
ax
Restore
length
Jn!
b a d_d I_II m I I
rei
A II DK
bad_dl_Ilmll:
hit
Die!
tell_dt_Ilmll endp
Copy the EPROM DT al leleclor ax In Ihe temporary GDT 10 Ihe allal
data legmenl 01 lel~ctor 51. Any Improper delcrlptors Dr Ilmltl
will caule Ihuldow~!
mov
mov
mov
mov
II I
mov
call
mov
mov
mov
pUlh
lodlw
call
ItO!W
movSiW
mOV!iW
mOV5W
pop
mov
proc
IS X t!!II
e! , II X
!1:1bxl.accell,DS_ACCESS;
e I ': [ b x I . rei , 0
a x, b x
ex, II I
I e I t_d I_II m I I
dl,gdt~delc-Inltlal_gdt
d I , d I
d I , t em p_d e I c - I nit I a I_g d I ;
d I
e!
d I , b x
endp
A-8
Polnl ES:DI at temporary delcrlptor
Mark delcrlplor .1 a dala segmenl
Clear re.erved word
Get limit of EPROM DT
Save for later
Ve r I f,y I t I I apr 0 per I I mit
Addrell EPROM GDT In DS
Gel leleclor tor temporary d~lcrlplor
Save offsel for laler ule ~I leleclor
Get allal legment Ilze
Verify II Is an eVen muiliple of
delcrlptors In length '
Pul length Into temporary
Copy remaining entrlel Into iemporary
ES now polnll al Ihe GDT allal area
DS now polnll al EPROM DT 01 dala
Copy segmenl 10 allal wllh zero fill
CX II copy counl, AX-CX II fill count
F a I I I n I 0 cop y_w I I h_ f I I I