Commodore Amiga - Figure 3-17 Data Layout for First Line-Right Half of Big Picture

Data for Line 2:
Location:
START+40
Leftmost
Display Word
START+42
Next Word
START+44
Next Word
START+78
Last Display
Word
Figure 3-17: Data Layout for First Line-Right Half of Big Picture
Now, the bit-plane pointers contain the value START+80.
The modulo (40) is added to
the pointers so that when they begin the data Cetch Cor the second line, the correct data
is fetched.
Data for Line 2:
Location: START+120
Leftmost
Display Word
START+122
Next Word
START+124
Next Word
START+158
Last Display
Word
Figure 3-18: Data Layout Cor Second Line-Right HalC of Big Picture
Remember, in high-resolution mode, you need to fetch twice as many bytes as
in low-
resolution mode. For a normal-sized display, you Cetch 80 bytes Cor each horizontal line
instead
oC 40.
Specifying the Data Fetch
The data-fetch registers specify the beginning and end positions for data placement on
each horizontal line of the display. You specify
data fetch in the same way as shown in
the section called "Forming a Basic Playfield."
68 Playfield Hardware