Information On The Display Screen - IBM 5110 User Manual

Using the
0
CC System Function to Control on the Display Screen
In the previous discussion on controlling the input from the keyboard,
the
Dee
function was used to place the 5110 in lowercase alphabetic
character mode. The
Dee
function can also be used to:
• Turn the display screen on or off during the execution of a
user-defined function. The primary advantage in turning the display
screen off is that the 5110 internal processing speed is increased by
approximately 18
%.
• Scroll the information on the display screen up or down.
To turn the display screen off during the execution of a user-defined
function, the left argument of the
Dee
function must be a 1 and the
right argument must be
O.
The display screen remains off until one of
the following occurs:
• The user-defined function completes execution.
• The
Dee
function is used to turn the display screen on again (both
the left and right arguments are specified as 1).
• A later statement in the user-defined function generates a result to
be displayed.
Since the
oee
function generates an explicit result, that result must be
assigned to a variable to prevent the display screen from being
immediately turned on and the result displayed. For example:
r:l.
::t
R~"l
[ICC
o.
When the
Dee
function is used to scroll the display screen up or
down, the left argument must be 4 and the right argument specifies
the number of lines to scroll up or down. For example:
F~~··4·
[ICC 8
Scrolls the information on the display screen
up
8
lines
Scrolls the information on the display screen
down 3 lines
In the previous examples, the explicit result of the
Dee
function is
assigned to a variable. Otherwise, the explicit result is displayed after
the
Dee
function scrolls the display screen up or down.
Console Control 63