90 rbuf spif-4 status definition, Table 90, “rbuf spif-4 status – Intel NETWORK PROCESSOR IXP2800 User Manual

Page 252

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252

Hardware Reference Manual

Intel

®

IXP2800 Network Processor

Media and Switch Fabric Interface

The status contains the following information:

The definitions of the fields are shown in

Table 90

.

3
1

3
0

2
9

2
8

2
7

2
6

2
5

2
4

2
3

2
2

2
1

2
0

1
9

1
8

1
7

1
6

1
5

1
4

1
3

1
2

1
1

1
0

9

8

7

6

5

4

3

2

1

0

RPROT

Element

Byte Count

SOP

EOP

Err

Le
n Err

Par Err

Abor

t Err

Null

Ty

pe

ADR

6
3

6
2

6
1

6
0

5
9

5
8

5
7

5
6

5
5

5
4

5
3

5
2

5
1

5
0

4
9

4
8

4
7

4
6

4
5

4
4

4
3

4
2

4
1

4
0

3
9

3
8

3
7

3
6

3
5

3
4

3
3

3
2

Reserved

Checksum

Table 90. RBUF SPIF-4 Status Definition

Field

Definition

RPROT

This bit is a 0, indicating that the Status is for SPI-4. It is derived from the RPROT input
signal.

Element

The element number in the RBUF that holds the data. This is equal to the offset in RBUF
of the first byte in the element, shifted right by six places

Byte_Count

Indicates the number of Data bytes, from 1 to 256, in the element (value 0x00 means
256). This field is derived from the number of data transfers that fill the element, and also
the EOPS field of the Control Word that most recently succeeded the data transfer.

SOP

Indicates whether the element is the start of a packet. This field is taken from the SOP
field of the Control Word that most recently preceded the data transfer for the first element
allocated after a Control Word. For subsequent elements (i.e., if more than one element
worth of data follow the Control Word) this value is 0.

EOP

Indicates whether the element is the end of a packet. This field is taken from the EOPS
field of the Control Word that most recently succeeded the data transfer.

Err

Error. This is the logical OR of Par Err, Len Err, and Abort Err.

Len Err

A non-EOP burst occurred that was not a multiple of 16 bytes.

Par Err

Parity Error was detected in the DIP-4 parity field. See the description in

Section 8.2.8.1

.

Abort Err

An EOP with Abort was received on bits [14:13] of the Control Word that most recently
succeeded the data transfer.

Null

Null receive. If this bit is set, it means that the Rx_Thread_Freelist timeout expired
before any more data was received, and that a null Receive Status Word is being pushed,
to keep the receive pipeline flowing. The rest of the fields in the Receive Status Word
must be ignored; there is no data or RBUF entry associated with a null Receive Status
Word.

Type

This field is taken from the Type field of the Control Word that most recently preceded the
data transfer.

ADR

The port number to which the data is directed. This field is taken from the ADR field of the
Control Word that most recently preceded the data transfer.

Checksum

Checksum calculated over the Data Words in the element. This can be used for TCP.

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