ROM Computer Magazine Archive ROM MAGAZINE ISSUE 1 — AUGUST/SEPTEMBER 1983 / PAGE 16

yELLOW bRICK rOADYellow Brick Road
By Peter Ellison
    This section in the magazine will be directed to poke & peek locations and other Atari memory locations that are looked up alot. This will make it faster for programming because you won't have to search for certain memory locations all through your reference manuals every time you program. Every month different locations will be given. Some of these locations can be found in the references pages that come with your computer but they won't be all on a few pages like the ones that will be in this section each issue.

    Many times for a game or business program a key must be pressed to continue during program execution and below is the location for each key on the keyboard. If no key is pressed PEEK(764) will be equal to 255

KEY PEEK(764) KEY PEEK(764)
A
63
W
46
B
21
X
22
C
18
Y
43
D
58
Z
23
E
42
1
31
F
56
2
30
G
61
3
26
H
57
4
24
I
13
5
29
J
1
6
27
K
5
7
51
L
0
8
53
M
37
9
58
N
35
0
50
O
8
+(LEFT) 6
P
10
*(RIGHT) 7
Q
47
- (UP) 14
R
40
=(DOWN) 15
S
62


T
45
RETURN 12
U
11
  ESC 28
V
16




    Below is short program that when run will draw a cross in the center of the screen using the four cursor control arrows.

5 GRAPHICS 5:COLOR 1:SETCOLOR 2,16,1
6 X=35:Y=20
10 T=PEEK(764):IF T=255 THEN 10:REM TO SEE IF KEY IS PRESSED
14 PLOT X,Y
20 POKE 764,255:REM RESET LOCATION 764 FOR NEXT KEY
30 IF T=6 THEN DRAWTO X-5,Y:? "LEFT"
35 IF T=7 THEN DRAWTO X+5,Y:? "RIGHT"
40 IF T=14 THEN DRAWTO X,Y-5:? "UP"
45 IF T=15 THEN DRAWTO X,Y+5:? "DOWN"
50 GOTO 10