Intel 80287, 80286 manual MovSiW

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
and	01·,7
cmp	a 1,7
pop	ax
Jn!	b a d_d I_II mI I
rei
bad_dl_Ilmll:
hit

Save lenglh

Look a I low order bit! MUlt be all one! Restore length

AII DK

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~!

	proc
mov	IS X t!!II
mov	e! , II X
mov	!1:1bxl.accell,DS_ACCESS;
mov	e I ': [ b x I . rei , 0
II I	a x, b x
mov	ex, II I
call	I e I t_d I_II mI I
mov	dl,gdt~delc-Inltlal_gdt
mov	d I , d I
mov	d I , t em p_d e I c - I nit I a I_g d I ;
pUlh	d I
lodlw
call
ItO!W
movSiW
mOV!iW
mOV5W
pop	e!
mov	d I , b x

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 Fa I I I n I 0 cop y_w I I h_ f I I I

endp

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