GX1 Datasheet, PDF (128/247 Pages) National Semiconductor (TI) – Processor Series Low Power Integrated x86 Solution

Integrated Functions (Continued)
4.4.3.3 Color Patterns
Setting the pattern mode to 11b (GX_BASE+8200h[9:8] =
11b), in the GP_RASTER_MODE register selects the color
patterns. 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 to the
frame buffer. The definition of the ROP value matches that
of the Microsoft API (application programming interface).
This allows Windows display drivers to load the raster oper-
ation directly into hardware. Table 4-21 illustrates this defi-
nition. Some common raster operations are described in
Table 4-22.
Table 4-21. 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 4-22. 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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