Atari 800 User Manual

84 User's Handbook to the Atari 400/800 Computers
POKE address, valu e
where the value specified is placed in the location given in
address. value and address can either be constants or variables.
For example, in
the following statement,
100 POKE 2000 , X
the value stored in variable X will be POKE'd into memory
location 2000.
The POKE statement cannot be used to change ROM. ROM is by
definition read-only memory, and cannot be altered with the
POKE statement.
Screen
Output Programming
The PRINT statement is used to display data on the screen. PRINT
statement output begins at the cursor's location. Therefore,
cursor positioning is the primary factor in sending output to the
screen.
As characters are output to the screen, the cursor position is
affected. Generally, the cursor moves one column to the right
after it has displayed a character. However, if a PRINT statement
ends
with a carriage return, the cursor will move to the
beginning of the next display line . Also, escape sequences can
be used to move the cursor in a direction other than towards the
right hand side of the screen. Finally, the POSITION statement
can be used
to move the cursor to any point on the screen. We
will cover each of these methods of cursor positioning as well as
other concepts of screen output programming in the next few
sections.
Using the Carriage Return in Cursor
Positioning
The carriage return is generated by pressing the Atari's Return
key. The
Return key generates the ASCII end-of-lin~ (EOL)
character. This character causes the cursor to advance to the
beginning of the next display line. The EOL character can also be
generated by using the CHR$ function with 155 (the ASCII code

Atari 800 Specifications

General

Brand	Atari
Model	800
Category	Desktop
Language	English