AMD Geode LX 800@0.9W - Manual (Page 267)

AMD Geode™ LX Processors Data Book 267
Graphics Processor Register Definitions 33234H
6.4.2.12 Vector Mode (GP_VECTOR_MODE)
Writing to this register configures the vector mode and initiates the rendering of the vector. If a BLT or vector operation is
already in progress when this register is written, the BLT pending bit in GP_BLT_STATUS (GP Memory Offset 44h)is set
and the vector is queued to begin when the current operation is complete. Software should not write to any register (other
than GP_HOST_SRC if required) while the BLT pending bit is set since it will corrupt the pending vector operation. Setting
the TH bit causes the vector operation to wait until the next VBLANK before beginning rendering. Software may still queue
another operation behind a throttled vector as long as the BLT pending bit is clear.
7:0 ROP/a
R
Raster Operations (ROP). Combination rule for source, pattern and destination when
performing raster operations. (See Section 6.3.10 "Raster Operations (ROP)" on page
251.)
Alpha Value (a
R
). Alpha value that can be used for some of the alpha compositing oper-
ations.
GP Memory Offset 3Ch
Type
WO
Reset Value 00000000h
GP_RASTER_MODE Bit Descriptions (Continued)
Bit Name Description
GP_VECTOR_MODE Register Map
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RSVD CP TH DR DN DJ YJ
GP_VECTOR_MODE Bit Descriptions
Bit Name Description
31:6 RSVD Reserved. Write to 0.
5 CP Checkpoint. Generates interrupt when this vector is completed if checkpoint interrupt is
enabled.
4 TH Throttle.
0: Operation begins immediately.
1: Operation waits until next VBLANK before beginning.
3 DR Destination Required.
0: Destination data is not needed for operation.
1: Destination data is needed from frame buffer.
2 DN Minor Direction.
0: Negative minor axis step.
1: Positive minor axis step.
1 DJ Major Direction.
0: Negative major axis step.
1: Positive major axis step
0 YJ Y Major.
0: X major vector.
1: Y major vector.