GXM Datasheet, PDF (123/244 Pages) National Semiconductor (TI) – Geode™ GXm Processor Integrated x86 Solution with MMX Support

Integrated Functions (Continued)
4.4.3.3 Color Patterns
Color patterns are selected by setting the pattern mode to
11 b in the GP_RASTER_MODE register. Bits [63:0] are
used to hold a row of pattern data for an 8-BPP pattern,
with bits [7:0] corresponding to the leftmost pixel of the
row. Likewise, bits [127:0] are used for a 16-BPP color
pattern, with bits [15:0] corresponding to the leftmost pixel
of the row.
To support an 8x8 color pattern, software must load the
pattern data for each row.
4.4.4 Source Expansion
The graphics pipeline contains hardware support for color
expansion of source data (primarily used for text). Those
pixels corresponding to a clear bit (0) in the source data
are rendered using the color specified in the
GP_SRC_COLOR_0 register (GX_BASE+810Ch), and
those pixels corresponding to a set bit (1) in the source
data are rendered using the color specified in the
GP_SRC_COLOR_1 register (GX_BASE+810Eh).
If the source transparency bit is set in the
GP_RASTER_MODE register, those pixels corresponding
to a clear bit (0) in the source data are not drawn.
4.4.5 Raster Operations
The GP_RASTER_MODE register specifies how the pat-
tern data, source data (color-expanded if necessary), and
destination data are combined to produce the output from
the graphics pipeline. The definition of the ROP valu
matches that of the Microsoft API. This allows Windows
display drivers to load the raster operation directly into
hardware. Table 4-22 illustrates this definition. Some com-
mon raster operations are described in Table 4-23.
Table 4-22. GP_RASTER_MODE Bit Patterns
Pattern
(bit)
Source
(bit)
Destination
(bit)
Output
(bit)
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
0
ROP[0]
1
ROP[1]
0
ROP[2]
1
ROP[3]
0
ROP[4]
1
ROP[5]
0
ROP[6]
1
ROP[7]
Table 4-23. Common Raster Operations
ROP
Description
F0h
CCh
5Ah
66h
55h
Output = Pattern
Output = source
Output = Pattern XOR destination
Output = Source XOR destination
Output = ~Destination
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