Atari 65XE User Manual

83
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.
10 ? CHR$(125) :? "Enter two numbers. Press Return after
each entry. "
20 INPUT N1,N2
30 GOSUB 90
40 ? "Their GCD is "; :? AN
50 POKE 752,1:POSITION 10,10: ? "Press Start to
continue."
60 IF PEEK(53279)<>6 THEN GOTO 60
78 POKE 752,0:? CHR$(125) :GOTO 10
80 REM ****SUBROUTINE****
90 AN=0:POKE 195,0:TRAP 130: M=(N1>=N2)*N1+(N2>N1)*N2:
N=(M=N1)*N2+(M=N2)*N1
100 IF INT(N1)<>N1 OR INT (N2)<>N2 THEN RETURN
110 P=M-INT (M/N)*N:M=N:N=P
120 IF P<>0 THEN GOTO 110
130 AN=M*(PEEK(195)=0):RETURN

Atari 65XE Specifications

General

CPU	MOS Technology 6502C
CPU Speed	1.79 MHz (NTSC) / 1.77 MHz (PAL)
RAM	64 KB
ROM	16 KB
Release Year	1985
Graphics	ANTIC and GTIA
Display Resolution	320x192
Sound	POKEY sound chip, 4 channels
Operating System	Atari BASIC
Ports	Joystick, Cartridge
Storage	External 5.25" floppy disk drive