LSI53C875 LSI Logic, LSI53C875 Datasheet - Page 201

• Manufacturer Part Number: LSI53C875
• Description: PCI to Ultra SCSI I/O Processor
• Manufacturer: LSI Logic

6.2 Block Move Instructions
6.2.1 First Dword
Performing a Block Move instruction, bit 5, Source I/O - Memory Enable
(SIOM) and bit 4, Destination I/O - Memory Enable (DIOM) in the
Mode (DMODE)
address resides in memory or I/O space. When data is being moved onto
the SCSI bus, SIOM controls whether that data comes from I/O or
memory space. When data is being moved off of the SCSI bus, DIOM
controls whether that data goes to I/O or memory space.
IT[1:0]
IA
Block Move Instructions
Instruction Type-Block Move
Indirect Addressing
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 be moved is in the second Dword
of this instruction.
When set, the 32-bit user data start address for the Block
Move is the address of a pointer to the actual data buffer
address. The value at the 32-bit start address is loaded
into the chip’s
a third longword fetch (4-byte transfer across the host
computer bus).
Direct
The byte count and absolute address are as follows.
Indirect
Use the fetched byte count, but fetch the data address
from the address in the instruction.
register determines whether the source/destination
Command
Command
DMA Next Address (DNAD)
Address of Pointer to Data
Address of Data
Byte Count
Byte Count
register using
[31:30]
DMA
6-5
29