5-34
SCSI SCRIPTS Instruction Set
5.6 Memory Move Instructions
For Memory Move instructions, bits 5 and 4 (SIOM and DIOM) in the
register determine whether the source or
destination addresses reside in memory or I/O space. By setting these
bits appropriately, data may be moved within memory space, within I/O
space, or between the two address spaces.
The Memory Move instruction is used to copy the specified number of
bytes from the source address to the destination address.
For memory moves where the data read is from the 64-bit address
space, the upper Dword of the address resides in the
register. For memory moves where the data is
written to the 64-bit address space, the upper Dword of the address
resides in the
Memory Move Write Selector (MMWS)
register.
Allowing the LSI53C1000 to perform memory moves frees the system
processor for other tasks and moves data at higher speeds than available
from current DMA controllers. Up to 16 Mbytes may be transferred with
one instruction. There are two restrictions:
•
Both the source and destination addresses must start with the same
address alignment (A[1:0]) must be the same). If the source and
destination are not aligned, then an illegal instruction interrupt
occurs. For the PCI
register setting to take
effect, the source and destination must be the same distance from a
cache line boundary.
•
Indirect addresses are not allowed. A burst of data is fetched from
the source address, put into the DMA FIFO and then written out to
the destination address. The move continues until the byte count
decrements to zero, then another SCRIPT is fetched from system
memory.
The
DMA SCRIPTS Pointer Save (DSPS)
and
registers are additional holding registers used during the Memory
Move. However, the contents of the
register are preserved.
Содержание LSI53C1000
Страница 6: ...vi Preface...
Страница 16: ...xvi Contents...
Страница 28: ...1 12 Introduction...
Страница 234: ...4 124 Registers...
Страница 314: ...6 40 Specifications This page intentionally left blank...
Страница 318: ...6 44 Specifications This page intentionally left blank...
Страница 344: ...6 70 Specifications This page intentionally left blank...
Страница 350: ...6 76 Specifications Figure 6 42 LSI53C1000 329 Ball Grid Array Bottom view...
Страница 352: ...6 78 Specifications...
Страница 360: ...A 8 Register Summary...
Страница 376: ...IX 12 Index...