HP Vectra Technical Reference Manual page 309

PUSH OS
INT HP_ENTRY
POP OS
,. EX-BIOS Destroys OS
,. Int 6FH for EX-BIOS
. Check
to
see if there is enough memory
to
allocate
5
paragraphs.
SUB BX, 0005H
eMP
BX, OX
JL NO_MEMORY_LEFT
ENOUGH_MEMORY_LEFT:
MOV BP, V_SYSTEM
MOV AH, F_RAM_RET
PUSH OS
INT HP_ENTRY
POP
OS
MOV MEMORY_SEG, BX
,. Create
a
new "Iast used OS" by
,. moving pointer towards "max OS".
,. Is "last used OS"
>
=
"max OS"?
,. Yes: Allocate
5
paragraphs.
,. HP vector 12H
,. function 20H
,. EX-BIOS Destroys OS
,. Int 6FH for EX-BIOS
,. Save this new memory pointer for
,. later use
,. Continue
,. No:
,
,. Typical thing
to
do here is
to
allocate more memory for the
,. the EX-BIOS RAM and reboot system.
Read a byte from CMOS. It verifies the checksum on the industry standard CMOS area and
returns RS_FAIL if the checksum is invalid.
On Entry: BP
=
V_SYSTEM (12H)
AH
=
F_CMOS_GET (22H)
BL
=
address of CMOS byte to read
On Exit: AH
=
Return Status Code
AL
=
byte of data from CMOS
Registers Altered: AX, BP, DS.
300 System Drivers