Advanced
BIOS
Functions
ASCII CONTROL
CODES
Table
6-1
summarizes the ASCII control codes which are available for the
CONOUT
routine in the BIOS.
Table 6-1 ASCII Control Codes
CONTROL
HEX
CHARACTER
CODE
ACTION
TAKEN
BEL
07H
Sound
bell tone
BS
08H Cursor backward
LF
OAH
Cursor down
VT
OBH
Cursor up
FF
OCH
Cursor forward
CR
ODH
Cursor to left margin
SUB
lAH
Erase screen
ESC
IBH
Introduce
an
escape sequence
RS
lEH
Cursor home
~
EXTENDED FUNCTION CALLS
Entry
to
the extended BIOS
is
accomplished through the 8086 software interrupt
#220. The extended function code
is
passed in register CL. Registers
DX,
DS,
and
AX
contain additional parameters as necessary. The status
of
the
GRAPH1,
GRAPH2,
CAPS,
and
AL T keys are returned in register
AH
for direct CBIOS calls.
All registers are automatically saved
upon
entry
and
restored
upon
exit from the
CBIOS. Table 6-2 lists the extended function calls.
6-9
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