Atari 800 User Manual

Atari BASIC Reference Guide 159
EXAMPLE
POKE 83,20
The previous example consists of a statement that changes the
right margin of the screen to column 20 . The value of the right
margin is stored in memory location 83.
POP
The POP statement causes a program to ignore the GOSUB or
ON / GOSUB statement that was executed last.
CONFIGURA
liON
POP
In
effect, a GOSUB or ON / GOSUB statement is converted to a
GOTO or ON / GOTO statement when POP is executed. The
program "forgets" that it is in a subroutine . As a result, when a
POP statement is executed, the next RETURN statement
branches
the program control to the line after the GOSUB
statement befor e the previous GOSUB statement. In other
words, the program "fo rgets" where the subroutine was called
from , so it returns to a previous GOSUB statement.
A
POP statement is used, in general, to exit a subroutine .
10 X = 5
20 Y = 10
EXAMPLE
30 GOSUB 100
40 END
100 PRINT X
110 IF X>O THEN POP : GOTO 130
120 RETURN
130 PRINT Y
140 END
RUN
5
10

Atari 800 Specifications

General

Processor	MOS Technology 6502
Processor Speed	1.79 MHz
ROM	10 KB
Graphics	ANTIC and GTIA chips
Release Year	1979
Display Resolution	up to 320 x 192
Colors	128 colors
Sound	4 channels
Storage	Cartridge, cassette, floppy disk
Ports	Cartridge, serial, monitor
Operating System	Atari OS