An apparatus and method for optimum transparent latch placement in a macro design
are provided. With the apparatus and method, a tree graph data structure is generated
to represent the design wherein nodes of the tree graph data structure represent
macros of the design. Each node of the tree graph data structure is augmented to
include a maximum latch number and a clocking domain. Any leaf nodes of the tree
graph data structure that cannot have latches placed in them, but have latch placement
requirements, have their latch placement requirements added to their parent node
if their parent node has more than one child node. The tree graph data structure
is traversed to find the most timing critical nodes with timing requirements that
have not been satisfied. A most timing critical path of these paths is identified.
Intermediate nodes along this path are examined to determine if there are any latch
placement requirements that must be met for the nodes. If these nodes have associated
latch placement requirements, the requirements are satisfied first. Then latch
placement along the critical path is performed in accordance with a one or more
project specific placement rules.
