Atari XL User Manual

Programming
19
is part of a program because each begins with a
number, and the program is stored for future use.
When you have typed in all the lines, you can
inspect the stored program by typing LIST (and
pressing RETURN, of course). The instructions are
listed in numerical order on the screen. You can
list parts of the program by specifying line
numbers. For example:
LIST 30, 50
LIST 20
lists all lines from 30 to 50
lists only line 20
If a program is very long, it will occu py more lines
than there is space for on one screen, so the screen
scrolls upwards to display the program. The listing
can be suspended by holding down CONTROL and
pressing 1. Repeating the CONTROL 1 sequence
will restart the listing.
To order the computer to act on the program you
use another BASIC command: RUN. Type this in
(followed by RETURN). This tells the computer to
read through the stored program and obey each
instruction in order. The program gives exactly the
same results as the multiple instructions in
Chapter 3.
A program may be R UN as many times as you like.
It will be stored in the computer's memory until
you switch it off. Programs can be altered or added
to at will. To alter an instruction, retype the Iine.:
If you enter:
40 PRINT "ATARI 600XL"
the original line 40 is replaced by the new one.
Extra lines are added by typing them as before:

Atari XL Specifications

General

Release Year	1983
CPU	MOS Technology 6502C
Graphics	ANTIC, GTIA
Sound	POKEY (4 channels)
Storage	Cassette tape
Ports	Cartridge
Operating System	Atari BASIC
CPU Speed	1.79 MHz
RAM	64 KB