LSI LSI53C1000, Technical Manual

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Block Move Instructions 5-5
SCSI bus, SIOM controls whether that data comes from the I/O or
memory space. When data is moved off of the SCSI bus, DIOM controls
whether that data goes to the I/O or memory space.
5.2.1 First Dword
This section describes the structure of the first SCSI SCRIPTS Dword.
Bits [31:24] are loaded into the DMA
Command register while bits [23:0]
are loaded into the DBC Register.
Figure 5.2 Block Move Instruction - First Dword
IT[1:0] Instruction Type - Block Move [31:30]
The configuration of these two bits define the SCRIPTS
instruction type. The Block Move Instruction is 0b00.
IA Indirect Addressing 29
When this bit is cleared, user data is moved to or from
the 32-bit data start address for the Block Move
instruction. The value is loaded into the chip’s address
register and incremented as data is transferred. The
address of the data to move is in the second Dword of
this instruction.
When the EN64DBMV bit in Chip Control One (CCNTL1)
is set, a third Dword is fetched to provide the upper
Dword of a 64-bit address. The upper Dword address is
fetched along with the instruction and loaded into the
Dynamic Block Move Selector (DBMS) register.
If the EN64DBMV bit is cleared, the upper Dword
address is copied from the
Static Block Move Selector
(SBMS) register.
Direct Addressing
The byte count and absolute address are as follows:
31 30 29 28 27 26 24 23 0
DCMD Register DBC Register
IT[1:0] IA TIA OPC SCSIP[2:0] TC[23:0]
Command Byte Count
Lower Dword Address of Data
Upper Dword address of data (EN64DBMV = 1)