Atari 130XE User Manual

HIGHER MATH
Your ATARI Computer is a fancy calculator. When you enter two
numbers into the program
below, the computer will tell you their
greatest common denominator. For
example, if you enter 690911 and
11214017,
you'll soon discover that their greatest common
denominator is 53147.
J.O ? CHR$ (J.25) :? "En"ter "two nUMbers. Press Re"turn af"ter
each en"tr!.l • "
20 INPUT NJ. .. N2
30 GOSUB ~O
40? "Their GCD is " ;:? AN
50 POKE 752 .. J.: POSITION J.O .. J.O: ? "Press S"tar"t"to
con"tinue."
60 IF PEEK(5327~)<)6 THEN GOTO 60
70 POKE 752 .. 0: ? CHR$ (J.25) : GOTO J.O
80 REM ****SUBROUTINE****
~O AN=O:POKE J.~5 .. 0:TRAP J.30: M=(NJ.)=N2)*NJ.+(N2)NJ.)*N2:
N=(M=NJ.)*N2+(M=N2)*NJ.
J.OO IF INT (NJ.) < )NJ. OR INT (N2) < )N2 THEN RETURN
J.J.O P=M-INT (M/N )*N: M=N: N=P
J.20 IF P<)O THEN GOTO J.J.O
J.30 AN=M*(PEEK(J.~5)=0): RETURN
83

Atari 130XE Specifications

General

Type	Home computer
Release year	1985
CPU	MOS Technology 6502C
CPU Speed	1.79 MHz
RAM	128 KB
ROM	24 KB
Graphics	ANTIC and GTIA chips
Manufacturer	Atari
Display resolution	320x192
Sound	POKEY chip, 4 channels
Storage	External floppy disk drive, cassette tape
Ports	2 joystick ports
Operating System	Atari BASIC