Справочник Пользователя для AMD LX 800@0.9W
AMD Geode™ LX Processors Data Book
325
Display Controller Register Descriptions
33234H
6.6.4.8
DC Line Size (DC_LINE_SIZE)
This register specifies the number of bytes to transfer for a line of frame buffer, compression buffer, and video buffer data.
The compressed line buffer is invalidated if it exceeds the CB_LINE_SIZE (bits [18:12]).
The compressed line buffer is invalidated if it exceeds the CB_LINE_SIZE (bits [18:12]).
Settings written to this register do not take effect until the start of the following frame or interlaced field.
DC_DV_TOP Bit Descriptions
Bit
Name
Description
31:24
RSVD
Reserved. These bits should be programmed to zero.
23:10
DV_TOP_ADDR
Dirty/Valid Region Top Address. When enabled via bit 0 (DV_TOP_EN), this field indi-
cates the size of the region to be watched for frame buffer accesses. When writes to this
region occur and the compression logic is in frame-dirty mode, the frame is marked as
dirty. (Writes outside this region, regardless of the settings in the DV_CTL register (DC
Memory Offset 088h), do not cause the frame to be marked as dirty in frame-dirty mode.)
The bits in this field correspond to address bits [23:10].
cates the size of the region to be watched for frame buffer accesses. When writes to this
region occur and the compression logic is in frame-dirty mode, the frame is marked as
dirty. (Writes outside this region, regardless of the settings in the DV_CTL register (DC
Memory Offset 088h), do not cause the frame to be marked as dirty in frame-dirty mode.)
The bits in this field correspond to address bits [23:10].
9:1
RSVD
Reserved. These bits should be programmed to zero.
0
DV_TOP_EN
Dirty/Valid Region Top Enable. This bit enables the top-of-region check for frame-dirty
mode. This bit should be cleared if the compression logic is NOT configured for frame-
dirty mode.
mode. This bit should be cleared if the compression logic is NOT configured for frame-
dirty mode.
DC Memory Offset 030h
Type
Type
R/W
Reset Value
xxxxxxxxh
DC_LINE_SIZE Register Map
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
RSVD
VID_LINE_SIZE
RSVD
CB_LINE_SIZE
RSVD
FB_LINE_SIZE
DC_LINE_SIZE Bit Descriptions
Bit
Name
Description
31:30
RSVD
Reserved. These bits should be programmed to zero.
29:20
VID_LINE_SIZE
Video Line Size. This value specifies the number of QWORDs (8-byte segments) to
transfer for each source line from the video buffer in YUV 4:2:2 mode. In YUV 4:2:0
mode, it specifies the number of QWORDs to transfer for the U or V stream for a source
line (2x this amount is transferred for the Y stream). In YUV 4:2:2 mode, this field must be
set to a multiple of four QWORDs -- bits [21:20] must be 0.
transfer for each source line from the video buffer in YUV 4:2:2 mode. In YUV 4:2:0
mode, it specifies the number of QWORDs to transfer for the U or V stream for a source
line (2x this amount is transferred for the Y stream). In YUV 4:2:2 mode, this field must be
set to a multiple of four QWORDs -- bits [21:20] must be 0.
19
RSVD
Reserved. This bit should be programmed to zero.
18:12
CB_LINE_SIZE
Compressed Display Buffer Line Size. This value represents the number of QWORDs
for a valid compressed line plus 1. It is used to detect an overflow of the compressed
data FIFO. When the compression data for a line reaches CB_LINE_SIZE QWORDs, the
line is deemed incompressible. Note that DC actually writes CB_LINE_SIZE + 4
QWORDs to memory, so if X QWORDs are allocated for each compression line, then
X - 4 + 1 (or X - 3) should be programmed into this register. Note also that the
CB_LINE_SIZE field should never be larger than 65 (041h) since the maximum size of
the compressed data FIFO is 64 QWORDs.
for a valid compressed line plus 1. It is used to detect an overflow of the compressed
data FIFO. When the compression data for a line reaches CB_LINE_SIZE QWORDs, the
line is deemed incompressible. Note that DC actually writes CB_LINE_SIZE + 4
QWORDs to memory, so if X QWORDs are allocated for each compression line, then
X - 4 + 1 (or X - 3) should be programmed into this register. Note also that the
CB_LINE_SIZE field should never be larger than 65 (041h) since the maximum size of
the compressed data FIFO is 64 QWORDs.
11:10
RSVD
Reserved. These bits should be programmed to zero.
9:0
FB_LINE_SIZE
Frame Buffer Line Size. This value specifies the number of QWORDs (8-byte seg-
ments) to transfer for each display line from the frame buffer.
ments) to transfer for each display line from the frame buffer.