HP Vectra Technical Reference Manual page 305

MOV
BP, V_SYSTEM ,. HP vector 12H for EX-BIOS.
MOV AH, F-'NS_FREEGETOS
,. Function 14H
MOV
01,
CS
,. Get CS, IP of ACME-'NT routines
MOV ES,OI
MOV
01,
offset ACME-'NT
PUSH OS ,. EX-BIOS Destroys OS
~
INT
HP_ENTRY ,. Int 6FH for EX-BIOS
POP OS
MOV
VECTOR~UMBER,
BX
,. Save the vector number
,. routines are installed.
,. ACME-'NT routine handles initialization and allocates 2
,. paragraphs from EX-BIOS RAM for its data segment.
ACME-'NT:
CMP AH, F_SYSTEM
,. Decode F_SYSTEM subfunction
JNE
NOT_SUPPORTED ,. SF-'NIT.
CMP
AL,SF-'NIT
JE ACME-'NIT
NOT_SUPPORTED: ,. Any unknown functions should
MOV AH, RS_UNSUPPORTEO
,. return with RS_UNSUPPORTED
IRET
,. in AH.
~
ACME-'NIT:
SUB BX,2
,. Decrement the "Iast used OS"
,. passed
to
us. This allocates 2
,. paragraphs and makes our data
,. segment the "last used OS". Make
,. sure
to
pass this new BX back
to
,. F-'NS_FREEGETOS code.
MOV OS,BX
,. Now
we
can initialize the data in
,. our segment.
ASSUME
OS:NOTHING
MOV ACME--.-A TTR, 55AAH
,. Put data into Attribute word
MOV
ACME~AME-'NOEX,
55AAH
,. Put
a
dummy index for now.
,. Initialize rest of data segment here.
MOV AH, RS_SUCCESSFUL
,. Always return this status if
,. successful initialization.
IRET
296 System Drivers