User's Manual

Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0
R
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12.3.14. BR13—BLT Raster OP, Control, and Destination Pitch
Memory Offset Address: 40034h
Default: 0000 xxxx
Attributes: RO; DWord accessible
31 30 29 28 27 26 25 24 23 16
Sol
Pat
Sel
X
Dir
Mon
Src
Trans
Mon
Pat
Trans
Src
Sel
Mode
Dyn
Col
En
Dynamic
Color
Depth
Raster Operation Select
15 14 13 0
Reserved.
Must be
Zero
Destination Pitch (Offset)
Bit Descriptions
31 Solid Pattern Select. This bit applies only when the pattern data is monochrome. This bit determines
whether or not the BLT Engine actually performs read operations from the frame buffer to load the
pattern data. Use of this feature to prevent these read operations can increase BLT Engine
performance, if use of the pattern data is indeed not necessary. The BLT Engine is configured to accept
either monochrome or color pattern data via the opcode field.
0 = This causes normal operation with regard to the use of the pattern data. The BLT Engine
proceeds with the process of reading the pattern data, and the pattern data is used as the pattern
operand for all bit-wise operations.
1 = The BLT Engine forgoes the process of reading the pattern data, the presumption is made that all
of the bits of the pattern data are set to 0, and the pattern operand for all bit-wise operations is
forced to the background color specified in the Color Expansion Background Color Register.
30 X Increment/Decrement Select.
0 = The bytes corresponding to the pixels within each scan line of data are written to the destination
starting with the bytes corresponding to the left-most pixel of each scan line at the destination
being the first to be written, and then proceeding in a rightward direction toward the right-most pixel.
1 = The bytes corresponding to the pixels within each scan line of data are written to the destination
starting with the bytes corresponding to the right-most pixel of each scan line at the destination
being the first to be written, and then proceeding in a leftward direction toward the left-most pixel.
29 Monochrome Source Transparency Mode. This bit applies only when the source data is in
monochrome. This bit determines whether or not the byte(s) at the destination corresponding to the pixel
to which a given bit of the source data also corresponds will actually be written if that source data bit has
the value of 0. This feature can make it possible to use the source as a transparency mask. The BLT
Engine is configured to accepted either monochrome or color source data via the opcode field.
0 = This causes normal operation with regard to the use of the source data. Where a bit in the source
data has the value of 0, the color specified in the background color register is used as the source
operand in the bit-wise operation for the pixel corresponding to the source data bit, and the bytes
at the destination corresponding to that pixel are written with the result.
1 = Where a bit in the source data has the value of 0, the byte(s) at the destination corresponding to
the pixel to which the source data bit also corresponds are simply not written, and the data at
those byte(s) at the destination are allowed to remain unchanged.