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S/UNI-ATLAS-3200 Telecom Standard Product Data Sheet
Preliminary
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990553, Issue 4
79
Name
Description
other search sequences are supported by the flexibility of this bit.
Left Leaf
This flag indicates if this node is a leaf. If Left Leaf is a logic 1, the
left branch is a leaf and the binary search terminates if the decision
bit is a logic 1. If Left Leaf is a logic 0, the Left Branch value points to
another node in the binary tree.
Left Branch
The pointer to the node accessed if the decision bit is a logic 1. If
Left Leaf is a logic 1, Left Branch contains the 16-bit address
identifying the VC Linkage Record and VC Table Record for that
connection. If Left Leaf is a logic 0, Left Branch contains the (up to)
17-bit address pointing to another Secondary Search Table entry.
Right Leaf
This flag indicates if this node is a leaf. If Right Leaf is a logic 1, the
Right Branch is a leaf and the binary search terminates if the decision
bit is a logic 0. If Right Leaf is a logic 0, the Right Branch field points
to another node in the binary tree.
Right Branch
The pointer to the node accessed if the decision bit is a logic 0. If
Right Leaf is a logic 1, Right Branch contains the 16-bit address
identifying the VC Linkage Record and VC Table Address for that
connection. If Right Leaf is a logic 0, Right Branch contains the 17-bit
address pointing to another Secondary Search Table entry.
The above encoding defines the binary search tree recursively.
The following special cases must be respected:
A binary tree with only one connection must have both the Left and Right Branches pointing to
the solitary VC Table Record. Both the Left Leaf and Right Leaf flags must be a logic 1.
If the Primary Search Table is not used (i.e. L
PHY
= L
A
= 0), then the primary key is considered to
be all-zeroes, and the Primary Pointer at SA[16:0] = 0x00000 contains the root of the Secondary
Search Tree.
If the Primary Search Table is in use, no root node shall use location SA[16:0]=0x00000,
although this location may be used for nodes at least one level down. A value of 0x00000 in the
Primary Search Pointer represents a null pointer.
10.3
VC Linkage Table
The VC Linkage table occupies the top half of the external SRAM address space, and contains
pointers to other context entries with which a VC is associated.
Table 7 VC Linkage Table
63
0
1 PHYID (6)
2
Reserved
(16)
PM 2
Active
(1)
1
PM 2
Address
(8)
PM 1
Active
(1)
1
PM 1
Address
(8)
VPC
Pointer
Active
(1)
2
VPC
Pointer
(16)
Shaded fields are reserved, and must be programmed to logic 0 for proper operation.