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ATARI Light Pen Operator's Manual
LOCATION
HEX
DEC
»CB
203
♦CC
204
*CD
205
♦CE
206
♦CF
207
»D0
208
«D1
209
*600
1536
*675
1653
FUNCTION
"PENBUF"
internal use - any value placed here
tiiill be destroyed.
"PENBUF" internal use - any value placed here
uiill be destroyed.
The value placed here determines the number of
reads
(see
above).
♦Buffered X coordinate* 0—X^159 (output)
Y coordinate* 0—¥"^95
(output)
column of pen*
0—COLUMN 39 (output)
row of pen*
0^R0WS23 (output)
"PENBUF"
routine
-
enter
it
here
End
of
"PENBUF"
routine
-
start
of
data
tables.
No.
bytes used
in tables is 2x(location 205-$CD)
♦Buffered
♦Buffered
♦Buffered
Start
of
♦Degree of buffering depends upon the value in location
♦CD=205.
Figure G. 1
PENBUF MEMORY USAGE
Memory Conservation - 62
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