STG3000X-RIVA128 STMicroelectronics, STG3000X-RIVA128 Datasheet - Page 52

• Manufacturer Part Number: STG3000X-RIVA128
• Description: 128-BIT 3D MULTIMEDIA ACCELERATOR
• Manufacturer: STMicroelectronics

RIVA 128
mode pixel format, the least significant bits of each color are located separately in the top byte of the pixel.
This also permits an 8:8:8 mode without gamma with <1% error if desired.
NOTE
This 32-bit representation can be extended to 64-bit and 128-bit widths by duplicating the 32-bit word in little-endian format.
Limitations on line lengths
Table 15. Permitted line length multiples
11.3 HARDWARE CURSOR
The RIVA 128 supports a 32x32 15bpp full color
hardware cursor as defined by Microsoft Win-
dows.
The cursor pattern is stored in a 2KByte bitmap lo-
cated in off-screen framestore. Details of program-
ming the hardware cursor are given in the RIVA
128 Programming Reference Manual [2]. Regis-
ters control cursor enabling/disabling, location of
cursor bitmap and cursor display coordinates. The
cursor data and it’s position should only be
changed during frame flyback. The cursor should
be disabled when not being used.
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31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
0 X X X X X X X
1 X
bpp
Number of pixels that the line
length must be a multiple of
Full color 5:5:5 format
Pixel complement
Transparency
Pixel inversion
R1 R0 G1 G0 B1 B0 R9 R8 R7 R6 R5 R4 R3 R2 G9 G8 G7 G6 G5 G4 G3 G2 B9 B8 B7 B6 B5 B4 B3 B2
8
4
Red gamma
Use of pixel input pins (FBD[31:0])
16
2
32
1
Pixel 0
128-BIT 3D MULTIMEDIA ACCELERATOR
Cursor format
The 5-bit RGB color components are expanded to
10 bits per color before combining with the graph-
ics display data. The expanded 10-bit color is com-
posed of the 5-bit cursor color replicated in the up-
per and lower 5-bit fields. The cursor pixels are
combined such that the cursor will overlay a video
window if present.
Cursor pixel bit 15 (A) is the replace mode bit.
When A=1, the cursor pixel replaces the normal
display pixel. If A=0, the expanded 30 bits of the
cursor color are XORed with the display pixel to
provide the complement of the background color.
Cursor pixels can be made transparent (normal
display pixel is unmodified) by setting to a value of
0x0000. To invert the bits of the normal display
pixel, the cursor pixel should be set to 0x7FFF.
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
A
Green gamma
Red
8
Green
7
6
Blue gamma
5
4
3
Blue
2
1
0