Browse Prior Art Database

Cell Name Resolution Feature And Variable Placement Field Image Feature Of a Structured Logic Placement Program

IP.com Disclosure Number: IPCOM000101713D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Related People

Seewann, E: AUTHOR

Abstract

Disclosed are two features of the program described in the preceding article. The first of these consists of a cell name resolution feature and the second consists of dynamically variable image construction.

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Cell Name Resolution Feature And Variable Placement Field Image Feature Of a Structured Logic Placement Program

       Disclosed are two features of the program described in
the preceding article. The first of these consists of a cell name
resolution feature and the second consists of dynamically variable
image construction.

      BTRTOGL1 places circuits (books) into "words" (rows) and words
into "pages".  It places them essentially sequentially in the order
of the books in the logic file. It reads a block from the logic file
and places a cell, the name of which can be completely specified in
the rules file, computes the location of the next block and places
that cell, etc., until it finishes a "word" by attaining a specified
macro width (or completely finishing the logic structure).

      However, cell names can be incompletely specified.  In other
words, the program may place circuits, the full name of which is not
(or cannot be) known until all books in the word have been placed.
The way this is accomplished is with a block rank feature.  After
placing a block, the program computes a block rank for that block and
compares it to the highest rank obtained thus far.  If the current
block has a higher rank, then the program makes this new rank the
"word" rank.  Thus, upon completion of a word, the program has
computed the highest rank of bits contained in the word. Attributes
of this rank, such as cell name prefix or suffix, can then propagated
to all ap...