U.S. patent application number 11/335597 was filed with the patent office on 2006-06-08 for method and apparatus for pattern ram sharing color look up table.
This patent application is currently assigned to VIA TECHNOLOGIES INC.. Invention is credited to Hill Cho, Roger Lin.
Application Number | 20060119605 11/335597 |
Document ID | / |
Family ID | 33098338 |
Filed Date | 2006-06-08 |
United States Patent
Application |
20060119605 |
Kind Code |
A1 |
Lin; Roger ; et al. |
June 8, 2006 |
Method and apparatus for pattern ram sharing color look up
table
Abstract
A method and apparatus for sharing the video memory of a graphic
chip includes the steps as follows: when the destination block of a
frame buffer executes color expansion, storing a color LUT to a
memory shared by both pattern and color LUT in a video memory, so
as to provide color expansion; and when the graphic engine accesses
a pattern memory, storing a pattern block to the memory shared by
both pattern and color LUT for the access of a graphic engine. By
the above-mentioned sharing mechanism, the physical layout area of
the graphic chip is reduced and the cost also drops.
Inventors: |
Lin; Roger; (Taipei, TW)
; Cho; Hill; (Taipei, TW) |
Correspondence
Address: |
LOWE HAUPTMAN GILMAN AND BERNER, LLP
1700 DIAGONAL ROAD
SUITE 300 /310
ALEXANDRIA
VA
22314
US
|
Assignee: |
VIA TECHNOLOGIES INC.
|
Family ID: |
33098338 |
Appl. No.: |
11/335597 |
Filed: |
January 20, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10851220 |
May 24, 2004 |
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11335597 |
Jan 20, 2006 |
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60472732 |
May 23, 2003 |
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Current U.S.
Class: |
345/541 |
Current CPC
Class: |
G06T 1/60 20130101; G10H
1/0058 20130101; G09G 2340/10 20130101; G09G 5/06 20130101; H04N
5/265 20130101; H04N 7/012 20130101; G09G 5/395 20130101; H04N
7/014 20130101; G09G 5/363 20130101; H04N 5/145 20130101 |
Class at
Publication: |
345/541 |
International
Class: |
G06F 15/167 20060101
G06F015/167 |
Claims
1-6. (canceled)
7. A graphic chip with a sharing video memory comprising: a video
memory for storing one sharing memory of a pattern and color LUT at
least, and a content of said sharing memory of pattern and color
LUT is adjusted in accordance with an access apparatus; and a
graphic engine for accessing and processing a plurality of pattern
blocks of said sharing memory of pattern and color LUT.
8. The graphic chip with a sharing video memory as recited in claim
7 comprising: a graph and video overlapping unit for receiving and
overlapping a destination block of a frame buffer and a graph and
video source.
9. The graphic chip with a sharing video memory as recited in claim
7 comprising: a frame buffer for storing a destination block at
least for a graph and video overlapping unit to perform an
overlapping procedure.
10. The graphic chip with a sharing video memory as recited in
claim 7, wherein if the access apparatus is a frame buffer, said
sharing memory of pattern and color LUT provided for storing said
color LUT, whereas if the access apparatus is said graphic engine,
said sharing memory of pattern and color LUT provided for storing
said plurality of said pattern blocks.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the usage of video memory,
especially to a method and apparatus for sharing the video memory
of a graphic chip.
[0003] 2. Description of the Prior Art
[0004] Generally, a graphic engine obtains the graphic block from a
source/destination/pattern block and the pattern block from the
other source/destination/pattern block to have various logic
executions, and then writes back to a frame buffer to be displayed
in a screen. Therein, the source block can be obtained from a CPU,
main memory and the frame buffer itself. The pattern block can also
be obtained from the CPU, pattern memory and pattern register to
write back to the destination block after executing a masking
operation. But among the obtained blocks, the pattern memory is the
largest block in a graphic chip. Taking a 16.times.16-pixel true
color video area as an example, a 768-byte (16.times.16.times.3)
memory is configured in a graphic chip (in true color, every pixel
includes 3 bytes to represent 3 primary colors) to work as a
pattern memory. FIG. 1A is the flowchart for the graphic engine of
a prior art processing a pattern block. Step 110 is to configure a
pattern block in a pattern memory. Step 130 is to access the
pattern block in the pattern memory if the graphic engine needs to
process the pattern block. And then Step 150 is to store the
processed pattern block in a frame buffer.
[0005] In another side, FIG. 1B is the color expansion flowchart of
a prior art. Step 120 is to configure a look up table (LUT) in a
video memory. Step 140 is to expand colors in accordance with the
LUT if the destination block of the frame buffer needs to expand
colors. And then Step 160 is to superpose and output the
color-expanded destination block and the other graph and video
source. In another word, the LUT stored in the video memory of a
graphic chip recovers the color index stored in a frame buffer, so
called pixel value, into the true color RGB 24-bit pixel value by
looking up the table when the displayed colors are 256 or under 256
color-scaled colors (indirect colors). When the displayed colors
are the above 256 color-scaled colors, the information of R, G and
B is not necessary to be recovered by looking up the LUT, because
the information included in R, G and B is already the original
information of the colors at this moment. It is called direct
color. Therefore, the LUT fails to work when the displayed colors
are above 256 color-scaled colors, but the LUT still occupies
certain area of the video memory.
[0006] FIG.2 is the graphic chip block diagram of a prior art,
including a graphic engine 220, a video memory 230, and a graph and
video superposition unit 240. The video memory 230 includes a
pattern memory 231 and a color LUT 232. Besides, a frame buffer can
store digitalized images temporarily; therefore, the graphic chip
can also include a frame buffer 250. A microprocessor 210 instructs
the graphic engine 220 to obtain the graphic block from the pattern
memory 231 of the video memory 230 and the frame buffer 250 to
write back to the frame buffer 250 after executing the pattern
block process, like masking operation, and then the graphic block
is sent directly to the graph and video superposition unit 240. If
the displayed colors are 256 or under 256 color-scaled colors, a
color expansion through the color LUT 232 is needed and then sent
graph and video superposition unit 240. Besides, if the input color
format is different from the covering color format, a color space
conversion (CSC) is also needed. For example, if the input format
is Y, Cb and Cr, but the output format is R, G and B, and the
output format is Y, Cb and Cr, a process of the color space
conversion is necessary to make the color formats in accordance
(because it is not the emphasis of this invention, it will not be
described in detail).
[0007] Because the usage moment of the pattern memory and color LUT
are exclusive and in timing order, and the access paths of the
pattern area and the color expansion are overlapped because they
both are in the pattern memory, how to reduce the layout of the
pattern memory in the graphic chip and how to use the video memory
in the graphic chip are the challenges that the technology field
has to face.
SUMMARY OF THE INVENTION
[0008] The present invention provides a method for sharing the
video memory of a graphic chip comprising the steps of storing a
color look up table (LUT) in a sharing memory of pattern and color
LUT in the video memory of the graphic chip while a destination
block of a frame buffer executes color expansion; and storing a
plurality of pattern blocks in the sharing memory of pattern and
color LUT for the access of the graphic engine while the graphic
engine accesses a pattern memory.
[0009] The present invention also provides a design method of a
graphic chip comprising a sharing memory of pattern and color LUT
is configured in a video memory of the graphic chip, wherein the
sharing memory of pattern and color LUT works as a color LUT when a
destination block of a frame buffer proceeds to color expansion,
and works as a pattern memory when a graphic engine accesses a
pattern block.
[0010] Again, the present invention provides a graphic chip sharing
video memory comprising a video memory for storing one sharing
memory of a pattern and color LUT at least, and the contents of the
sharing memory of pattern and color LUT adjusted in accordance with
an access apparatus; and a graphic engine for accessing and
processing a plurality of pattern blocks of the sharing memory of
pattern and color LUT.
[0011] The physical layout area of a graphic chip can be reduced so
that the cost drops by a method for sharing the video memory of a
graphic chip and the design method of the graphic chip based on the
present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1A is the flowchart for the graphic engine of a prior
art to process a pattern block;
[0013] FIG. 1B is the flowchart of the color expansion of a prior
art;
[0014] FIG. 2 is the block diagram of the graphic of a prior
art;
[0015] FIG. 3 is the method for sharing the video memory for a
graphic chip in accordance with a preferred embodiment of the
present invention; and
[0016] FIG. 4 is the block diagram of a graphic chip in accordance
with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Some embodiments of the present invention will be described
in detail as the following. But, besides the description in detail,
the present invention can be implemented in the other embodiments
broadly, and the scope of the present invention is not limited, in
accordance with the following claims.
[0018] For providing clearer description and understanding the
present invention more easily, every part of the drawings is not
drew in its relative dimensions. Certain dimensions and the other
ratios of the relative scales are exaggerated. The irrelevant
details are not drawn completely for the simplicity of the
drawings.
[0019] FIG. 3 is the method for sharing the video memory of a
graphic chip in accordance with a preferred embodiment of the
present invention. Step 310 judges the access apparatus and content
of the video memory. If the access apparatus is a graphic engine
and the content of the sharing memory of pattern and color LUT is
the pattern block, the sharing memory of pattern and color LUT is
accessed in Step 350. If the content of the sharing memory of
pattern and color LUT is the color LUT, the copy of the pattern
block is written to the sharing memory of pattern and color LUT in
Step 330, and the sharing memory of pattern and color LUT is
accessed in Step 350. In another side, if the destination block of
a frame buffer proceeds to color expansion in Step 320, and the
content of the sharing memory of pattern and color LUT is the color
LUT, the sharing memory of pattern and color LUT is accessed in
Step 350. If the content of the sharing memory of pattern and color
LUT is the pattern block, the copy of the color LUT is written to
the sharing memory of pattern and color LUT in Step 340, and then
the sharing memory of pattern and color LUT is accessed in Step
350.
[0020] FIG. 4 is the block diagram of the graphic chip in
accordance with the present invention. The graphic chip comprising
a graphic engine 420, a video memory 430, and a graph and video
overlapping unit 440, wherein the video memory 430 further
comprising a sharing memory of pattern and color LUT 431, and the
graphic chip can also comprising a frame buffer 450. A
microprocessor 410 instructs the graph engine 420 to obtain the
graphic block from the sharing memory of pattern and color LUT of
the video memory 430 and the frame buffer 450 to write back to the
frame buffer 450 after executing the pattern block process, like
masking operation, and then the graphic block is sent directly to
the graph and video overlapping unit 440. In another side, if the
displayed colors in the destination block are 256 or under 256
color-scaled colors, the color LUT stored in the sharing memory of
pattern and color LUT 431 is accessed to execute color expansion,
and then sent to the graph and video superposition unit 440,
including reading the copy of the color LUT 462 in the external
memory 460 and then writing to the video memory 430 for color
expansion. In another word, because of sharing the sharing memory
of pattern and color LUT 431 (like an SRAM), an external memory 460
(like an SDRAM) can be provided to store the copy of the pattern
block 461 and the copy of the color LUT 462 for different access
needs. If the content of the sharing memory of pattern and color
LUT 431 is the pattern block, and the destination block of the
frame buffer 450 will execute color expansion, the copy of the
color LUT 462 can be written to the sharing the sharing memory of
pattern and color LUT 431 for color expansion. In another side, if
the content of the sharing memory of pattern and color LUT 431 is
the color LUT, and the graphic engine 420 will access the pattern
memory, the copy of the pattern block 461 can be written to the
sharing memory of pattern and color LUT 431 for the access of the
graphic engine 420.
[0021] While the described embodiment represents the preferred form
of the present invention, it is to be understood that modifications
will occur to those skilled in that art without departing from the
spirit of the invention. The scope of the invention is therefore to
be determined solely by the appended claims.
* * * * *