MB86296 Datasheet, PDF (76/352 Pages) Fujitsu Component Limited. – PCI Graphics Controller Specification

FUJITSU LIMITED PRELIMINARY AND CONFIDENTIAL
MB8629x scans the logical graphics space as if the entire space is rolled over in both the horizontal
and vertical directions. Using this function, if the display frame crosses the border of the logical
graphics space, the part outside the border is covered with the other side of the logical graphics space,
which is assumed to be connected cyclically as shown below:
Logical Frame Origin
64 w
Additionally
drawn area
L
Previous display
origin
New display origin
Fig. 5.3 Wrap Around of Display Frame
The expression of the X and Y coordinates in the frame and their corresponding linear addresses (in
bytes) is shown below.
A(x,y) = x × bpp/8 + 64wy (bpp = 8 or 16)
The origin of the displayed coordinates has to be within the frame. To be more specific, the
parameters are subject to the following constraints:
0 ≤ DX < w × 64 × 8/bpp (bpp = 8 or 16)
0 ≤ DY < H
DX, DY, and DA have to indicate the same point within the frame. In short, the following relationship
must be satisfied.
DA = OA + DX × bpp/8 + 64w × DY (bpp = 8 or 16)
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Specification Manual Rev0.1