Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0

R

15.4.12.2. AWINSZ—Alpha Blend Window Size Register

Memory Address Offset:

 

74h (R/W)

 

 

 

 

 

 

On-chip Reg. Mem Addr Offset:

30174h (RO; debug path)

 

 

 

 

Default Value:

 

00h

 

 

 

 

 

 

Access:

 

 

see address offset above

 

 

 

 

Size:

 

 

32 bits

 

 

 

 

 

 

31

27

26

16

15

11

10

0

 

 

 

 

Reserved

Alpha Blend Vertical

 

Reserved

 

Alpha Blend Horizontal

 

 

 

 

 

 

Size

 

 

 

Size

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bit

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

31:27

Reserved.

 

 

 

 

 

 

 

 

 

 

 

 

26:16

Alpha Blend Vertial Size. Determines where on the display screen coordinates the overlay display are

 

 

 

alpha blended. Alpha Blend Vertical Size in lines (never specifies scan lines off the active display)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15:11

Reserved.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10:0

Alpha Blend Horizontal Size. Determines where on the display screen coordinates the overlay

 

 

 

 

 

display are alpha blended. Alpha Blend Horizontal Size in pixels (never specifies pixels off the active

 

 

 

display)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15.5.Overlay Flip Instruction

DWord

Bit

Description

 

 

 

0

31:29

Client: xxh

 

 

 

 

28:23

Function Index:

 

 

 

 

22:16

Instruction Target

 

 

 

1

31:0

Register Update Address:

 

 

 

Do not use the “Wait for VBLANK” mechanism to force a sequence of overlay flips. Use the “Wait for Scan Lines” mechanism with the scan line set up to be at least 1 scan line after vertical blank start to force the loading of the next Overlay x Register Update Address which will take effect after the next displayed overlay frame. For Intel® 810 chipset, the Overlay Update Address register can be loaded either before or after the “Wait for VBLANK” (primary display VBLANK). Future implementations should create a “Wait for Overlay Flip Not Pending” mechanism if this becomes an issue, especially since the Overlay may not use the primary display’s timing generator in the future.

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Image 299
Intel 815 manual Overlay Flip Instruction, AWINSZ-Alpha Blend Window Size Register