User's Manual

Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0
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12.3.15. BR14—Destination Width & Height
Memory Offset Address: 40038h
Default: None
Attributes: RO; DWord accessible
BR14 contains the values for the height and width of the data to be BLT. If these values are not correct,
such that the BLT Engine is either expecting data it does not receive or receives data it did not expect,
the system can hang.
31 29 28 16
Reserved. Must
be Zero
Destination Height
15 13 12 0
Reserved. Must
be Zero
Destination Byte Width
Bit Descriptions
31:29 Reserved. Must be Zero.
28:16 Destination Height. These 13 bits specify the height of the destination data in terms of the number of
scan lines. This is a working register.
15:13 Reserved. Must be Zero.
12:0 Destination Byte Width. These 13 bits specify the width of the destination data in terms of the number
of bytes per scan line. The number of pixels per scan line into which this value translates depends upon
the color depth to which the graphics system has been set.
NOTES: This is a working register. If BR14 is read while the BLT Engine is busy, the contents are unpredictable.
The value contained in this register while the BLT Engine is busy has no relationship to the programmed
value that can be read when the BLT Engine is idle.