Intel 80286, 80287 manual System .INITIALIZATION

80286 SYSTEM .INITIALIZATION

Define the templ.te for . temporary GDT u.ed to locate the Initial GDT and .tock. Thl. data will be copied to location O.

Thl5 .pace Is 01.0 u.ed for a temporary stack and finally .erve' a. the T55 wrillen inlo when entering Ihe Initial T55.

Inltlal_gdt gdt_de.c Idl_de!C lemp_de.c

org

de.c <)

de.c <)

de. c <)

de.c <)

Place remaining code below power _u p

Fill e r and nul I IDT de.crlptor De.crlptor for EPROM GDT

De.crlptor for EPROM IDT Temporary de.crlptor

Define a de5Crlptor Ihat will point the GDT at location· D.

Thl. de.crlplor will al.o be loaded Inlo 5510 define Ihe Initial prolected m~de slack .egmenl.

desc	<e n d_g d I - I n I I I a I_g d t - 1 , 0 , 0 , DS_A CCE5 S , 0 )
Define the	TS5 descriptor u.ed to	allow the t •• k .wltch to the
flr . t task to overwrite thl. region		of memory. The TS5 will overlay

the Initial GDT and .tack at ·Iocatlon D.

desc

Define the Initial .tack space and filler fo~ the end of the TSS.

	dw	8 dup (0)
	I abe I	word
.tart_polnter	lobe I	dword
	dw	o, • tar t_ t ask	; Pointer to Inilial la.k

Define	lemplate
ta.k_entry	• I	r u c
T55_.el	dw
T55_alla.	dw
LDT_alla.	dw
ta.k_entry	end.
	ta.k_entry
	d w	0

re.et_.tartup:

cII c I d

lor	d I , d I
mov	d.,dl
mov	!!!I,dl

for the la.k definition 11.1.

Define layout of ta.k de.crlptlon

Selector for TSS

Data .egment all •• for TSS

Dolo .egment alia. for LDT If any

<~tarl_task,.tart_TSS_alla.,.lar~_LDT_alla.)

;Terminate II . t

No Interrupt. allowed! U.e autolncrement mode

Point ES:DI at phy.lcal addre •• DDDOODH

mov	• • , d I	Set .tack at end of re.erved area
mov	• P , en d_g d t - I nit I a I_g d t

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