Field Name
Description
Bits
Default
HEAD_SIZE[7:0]
Head Size.
The number of bytes required for the compression
expansion calculation.
0 - 255: Head size in bytes
15:8
0
The Compression engine will set the cmp_expansion
bit (defined in the desc_result and result ring) to
one if
len(cmp) + Head_Size >= len(raw).
CMP_CM
Compression Count Mode.
If this bit is set to zero, the compression source
count in the 820x begins to decrement after the last
header byte has been passed through the 820x. If
this bit is set to one, the compression source
counter begins to decrement after the last byte
processed by the previous processing engine. Please
refer to Section 3.1.3.10, “IPsec Packet Processing"
for more information.
7
0
0
820x begins to decrement the compression
source count after the last header byte
1
820x begins to decrement the compression
source count after the last byte processed by
the previous processing engine
Reserved
6:2
1:0
0
0
Reserved.
CMP_AG[1:0]
Compression Algorithm.
Used to set the compression algorithm.
00 LZS algorithm
01 eLZS algorithm
10 GZIP algorithm
11 Reserved
3.1.2.4
Desc_cmd_enc
This descriptor defines the encryption engine related parameters. Desc_cmd_enc is 8 bytes
for either 32-bit or 64-bit addressing modes.
ENC_Source_Count[23:0]
ENC_Header_Count[7:0]
63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32
Sector_Size[23:0]
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
820x – Data Sheet, DS-0157-D
Page50
Hifn Confidential
EXAR [ EXAR CORPORATION ]
