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Printer
Support
The
following interrupts
support the
printer:
INT 56h, Function
-
Request
Printer
Entry:
AH
=
(function
code)
Exit:
AL =
Standard
BIOS
error
code
This
function called
prior to
accessing
the
printer.
Its
purpose
is
to
mark
the
printer
device as
in
use.
INT
56h,
Function
1
-
Initialize
Printer
Entry:
AH
=
1
(function
code)
Exit:
AL=
Standard
BIOS
error
code
This function
is
called
once
after
successfully requesting the
printer.
Its
purpose
is
to
perform
any
initialization
required before
sending an
output
stream
to
the
printer.
INT
56h,
Function
2
-
Print
Character
Entry:
AH
=
2
(function
code)
AL =
character
to
print
Exit:
AL =
Standard
BIOS
error
code
INT
56h,
Function 3
-
Print
Screen
Entry:
AH
=
3
(function
code)
Exit:
AL=
Standard
BIOS
error
code
This function
may
be implemented
as
either a
graphic
print
screen
if
graphic output
on
the
printer
is
supported, or
as an alpha
only
print
screen
if
graphic
printer
output
is
not supported.
If
graphic output
is
supported,
correction
for different
aspect
ratios
between
LCD
screen
and
printer
may
be
provided, but
is
not required.
156
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