Conexant Fusion 878A, Руководство пользователя

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2.0 Functional Description
Fusion 878A
2.12 DMA Controller PCI Video Decoder
2-42
Conexant
100600B
Each RISC instruction consists of 1 to 5 DWORDs. The 32-bits in the
DWORDs relay information such as the opcode, target address, status codes,
synchronization codes, byte count/enables, and start/end of line codes.
The SOL bit in the WRITE and SKIP instructions indicates that this particular
instruction is the first instruction of the scan line. The EOL bit in the WRITE and
SKIP instructions indicates that this particular instruction is the last instruction of
the scan line. An EOL flag from the FIFO and the last DWORD for the scan line
coincide with finishing the last instruction of the scan line. If the FIFO EOL
condition occurs early, the current instruction and all instructions leading up to
the one that contains the EOL flag will be aborted. If there is only one instruction
to process the line, both SOL and EOL bits will be set.
WRITE, WRITEC, and SKIP control the processing of active pixel data stored
in the FIFO. These three instructions alone control the sequence of packed mode
data written to target memory on a byte resolution basis. The WRITEC
instruction does not supply a target address. Instead, it relies on continuing from
the current DMA pointer contained in the target address counter. This value is
updated and kept current even during SKIP mode or FIFO overruns. However,
JUMP 0111 2 Jump the RISC program counter to the jump address. This allows unconditional
branching of the sequencer program.
DWORD0:
[15:0] Reserved
[23:16] Reset/Set RISC_STATUS
[24] IRQ
[27:25] Reserved
[31:28] Opcode
DWORD1:
[31:0] Jump address DWORD-aligned
SYNC 1000 2 Synchronize all data in FIFO until the RISC instruction status bits equal the FIFO
status bits.
DWORD0:
[3:0] Status
[14:4] Reserved
[15] RESYNC A value of 1 disables FDSR errors
[23:16] Reset/Set RISC_STATUS
[24] IRQ
[27:25] Reserved
[31:28] Opcode
DWORD1:
[31:0] Reserved
Table 2-10. RISC Instructions (5 of 5)
Instruction Opcode DWORDs Description