Apple IIe - Page 238

238 Apple lie Users Handbook
A
memory byte may be divided as follows.
5 4 3 2 1 0
x
y
z
To pack the binary codes in Table 6-3 into memory locations,
perform the following steps. Place the binary code for vector #1
into section Z of a byte.
Jx x I x x x
0 1 0
Place the binary code for vector #2 into position Y.
Ix x I o 1 o I o 1 o I
If the next vector is a move vector, place it in section X. In our
example , the square, it is not a move vector (vector #3 =plot-).
If the next vector is not a move vector , place two zeros in section
x.
(o o 0 1 0
0 1 0
Notice that a" move - f" vector may not be placed in section X.
In fact, in any byte, a "move - f" vector must always have
another command to the left of it . This is due to rule 2, as stated
previously .
After a byte has been filled, start filling the next byte in a similar .
manner (vector #3 into section Z of byte 2) .
x
y
0 1 0
1 0 1
z
byte 1
byte 2