
P.90
D0-10
D11-15
Right Clipping position bit 0-10 of bit 0 to 10
Reserved
Bit 0-10
These bits are conjunction with GAREG 11,12,13 to define a rectangular area . Any pixel inside and
on the boundary of the rectangular area can be updated during a Graphics Command operation .
Reserved
Bit 11-15
GAREG Hex 15 : Raster Operation Register
This is a read/write register.
Default value after hardware reset is Hex 00,00.
Default port address 57C4.
PCI port address low 54.
D0-7
D8-10
D11-15
Raster operation code bit 0 to 7
Scan line width selection bits
Reserved
Bit 0-7
Raster Operation as defined by Microsoft Windows.All logical operation of Source,Pattern, and Destination
data are supported.
Bit 8-10
These bit are used to set the scanline offset in pixel unit.
Bit-10 Bit-9
Bit-8
Definition
0
0
0
1024 pixels per line
0
0
1
640 pixels per line
0
1
X
800 pixels per line
1
0
0
2048 pixels per line
1
0
1
1280 pixels per line
1
1
X
1600 pixels per line
Bit 11-15
Reserved.
GAREG Hex 16 : Graphics Engine Control Register
This is a read/write register.
Default value after hardware reset is Hex 00,00.
Default port address 5BC4.
PCI port address low 58.
D0
D1
D2
D3
D4
D5
D6
D7
D8-9
D10
D11
D12
D13-15
X direction
Y direction
Source select/Major movement
Destination select/Last pixel display enable
Graphics function mode select
Background transparency enable for color expansion and line drawing
Transparency enable
Rectangular clipping enable
Source format
Transparency polarity
Rectangular clipping polarity
Line drawing pattern width select
Reserved
Bit 0
This bit is used to select the direction of X direction. A logical 0 indicates in the increasing direction
, and a logical 1 indicates in the decreasing direction.
This bit is used to select the direction of Y direction . A logical 0 indicates in the increasing direction
, and a logical 1 indicates in the decreasing direction .
This bit selects the source as either the screen memory or the host CPU memory for BITBLT opera-
Bit 1
Bit 2