Intel
®
81341 and 81342—Application DMA Unit
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
502
Order Number: 315037-002US
5.7.6
Zero Result Buffer Check
The ADMA can be used to verify parity across memory blocks specified by the SARx
registers. As with XOR operations, descriptors are used to specify the memory blocks
on which the ADMA performs the Zero Result Buffer Check.
illustrates a Zero
Result Buffer Check performed by the ADMA. After processing all source data and
depending on the setting of the Status Write Back Enable in the ADCR, the ADMA either
updates the Result Buffer Not Zero and Transfer Complete bits of the fourth word of the
descriptor (ABCR) or signals an interrupt to the Intel XScale
®
processor and suspend
ADMA operation.
Figure 66. An Example of Zero Result Buffer Check
A000 0400H
Block 1
MSB
LSB
A000 0800H
A000 0C00H
A000 1000H
bitwise-XOR
(64-bit wide)
bitwise-XOR
(64-bit wide)
bitwise-XOR
(64-bit wide)
1024 bytes
1024 bytes
1024 bytes
1024 bytes
Block 2
Block 3
Block 4
SAR2 = A000 0C00H
SAR3 = A000 1000H
SAR1 = A000 0800H
SAR0 = A000 0400H
ABCR = 0000 0400H
ADCR = 0000 009FH
Control Register Values
I/O Processor Local Memory
byte 1
byte 8
...
...
...
Byte 1..8 Checked for 00H with
result indicated when not 00H
B6232-01
Note: All of the Source Data Streams are required to be in Local Memory for the Zero
Result Check operation to operate properly. The ADMA does not support Source Data
streams for Zero Result Check operations that are located in Host Memory or the
Internal Bus.