Atari 800 Basic Reference Manual

APPENDIX I
MEMORY
LOCATIONS
Note: Many of these locations are of primary interest to expert programmers and are included here as a
convenience . The labels given are used by Atari programmers to make programs more readable.
LABEL
APPMHI
RTCLOK
SOUNDR
LMARGIN,
RMARGIN
ROWCRS
COLCRS
OLD
ROW
OLDCOL
NEWROW
NEW COL
RAMTOP
LOMEM
MEMTOP
STOPLN
ERRSAV
PTABW
FRO
DECIMAL
LOCATION
14,15
18,19,20
65
77
82,83
84
85,86
90
91,92
93
96
97,98
106
128,129
144 ,145
186,187
195
201
212,2 13
HEXADECIMAL
LOCATION COMMENTS AND DESCRIPTION
DE
Highest location used by BASIC (LSB, MSB)
12,13,14 TV frame counter (1 / 60 sec .) (L SB, NSB, MSB )
41
Noisy I/0 Flag (0 =quiet )
Attract Mode Flag (128 =Attract mode)
52 ,53 Left, Right Margin (Defaults 2, 39)
54
Current cursor row (graphics window).
55,56
Current cursor column (graph ics window ).
SA Previous cursor row (graphics window) .
5B
Previous cursor column (graphics window).
5C
Data under cursor (graphics w indow unle ss mode
0).
60
Cursor row to which DRA WTO will go .
61,62
Cursor column to which DRA WTO goes.
6A
Actual top of memory (number of pages ).
80,81
BASIC
low memory pointer .
90,91
BASIC
top of memory pointer.
BA,BB
Line number at which STOP or TRAP occurred
(2-byte binary number).
C3
Error number.
C9
Print tab width (defaults to 10 )
D4,D5
Low and high byte s of value to be returned
to
BASIC from USR function.
App e ndix 1-1

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