User's Manual

Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0
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12.3.2. BR01—Setup BLT Raster OP, Control, and Destination Offset
Memory Offset Address: 40004h
Default: 0000 xxxx
Attributes: RO; DWord accessible
BR01 contains the contents of the last Setup instruction DWord 1. It is identical to the BLT Raster OP,
Control, and Destination Offset definition, but it is used with the following instructions: PIXEL_BLT,
SCANLINE_BLT, and TEXT_BLT.
31 30 29 28 27 26 25 24 23 16
SolPat Rsvd Mono
Src
Trans
Mono
Pat
Trans
Src
Sel
Mode
Dyn
Color
Depth
Enable
Color
Depth Raster Operation
15 14 13 0
Rsvd 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 in order 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 Reserved. Must be Zero.
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. Wherever 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 = Wher 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.