Block Move Instructions
5-7
Note:
Using indirect and table indirect addressing simultaneously
is not permitted; use only one addressing method at a time.
Prior to the start of an I/O, load the
register with the base address of the I/O
data structure. Any address on a Dword boundary is
allowed.
After a Table Indirect opcode is fetched, the
is added to the 24-bit signed
offset value from the opcode to generate the address of
the required data; both positive and negative offsets are
allowed. A subsequent fetch from that address brings the
data values into the chip.
For a MOVE instruction, the 24-bit byte count is fetched
from system memory. Then the 32-bit physical address is
brought into the LSI53C896. Execution of the move
begins at this point.
SCRIPTS can directly execute operating system I/O data
structures, saving time at the beginning of an I/O
operation. The I/O data structure can begin on any Dword
boundary and may cross system segment boundaries.
There are two restrictions on the placement of pointer
data in system memory:
•
The eight bytes of data in the MOVE instruction must
be contiguous, as shown below, and
•
Indirect data fetches are not available during
execution of a Memory-to-Memory DMA operation
64-Bit Addressing
If the enable 64-bit Table Indirect Block Move
(EN64TIBMV) bit is clear, then table indirect block moves
will remain as 2 Dword opcodes plus a 2 Dword table
entry and the upper 32 bits of the address will be pulled
from the
Static Block Move Selector (SBMS)
(which is
loaded manually) when doing data transfers during block
move operations.
00
Byte Count
Physical Data Address
*
Содержание LSI53C896
Страница 6: ...vi Preface...
Страница 16: ...xvi Contents...
Страница 88: ...2 62 Functional Description...
Страница 112: ...3 24 Signal Descriptions...
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Страница 338: ...6 70 Specifications Figure 6 40 LSI53C896 329 BGA Bottom View...
Страница 340: ...6 72 Specifications...
Страница 346: ...A 6 Register Summary...
Страница 362: ...IX 12 Index...