Apple IIe - Page 281

The
80-Column
Board
281
BASIC
Support of the
80-Column
Board
The
BO-column
board
does
not
effect
the
functioning
of
the
majority
of
BASIC's
majority
commands.
Only
four
of
the
commands
function
differently
when
used
with
the
BO-column
board. These are
as
follows:
Tabbing
HOME
FLASH
HTAB
INVERSE
Horizontal
tabbing,
while
using
the
BO-column
board,
does
not
operate
in
exactly
the
same
manner
as
it
does
without
the
board.
If
the
numeric
argument
of
the
HTAB
function
is
greater
than
40,
an
automatic
wrap-around
occurs.
If
an
HT AB
is
attempted
to
any
of
the
columns
greater
than
40, an
automatic
wrap-around
occurs
even
though
the
display
is
capable
ot
80
columns.
Therefore,
nothing
is
dis~ayed
in
the
last
40
columns.
This
is
remedied
by
the
substitute HT AB
command.
This
com-
mand
is
as
follows:
POKE
1403,XX
XX
represents
the
column
number
to
which
the
next
screen
output
will
be
directed
. HT AB
XX
may
still
be used
for
the
first
40
columns
if
the
programmer
so
desires. The substitute
command
will
only
operate
correctly
when
the
BO-column display
is
being
used.
100 VTAB 5
110
POKE 1403,65
120
PRINT
"OUTPUT"
Execution
of
the
previous
example
will
output
the
text,
OUTPUT,
at screen
location
65,6 (65th
column,
5th row).