Weight based look up table collapsing for programmable logic devices

A computer readable medium on which is stored a computer program which when executed by a computer system performs a method of selectively collapsing connections between a plurality of look up tables (LUTs) of a logic design, when executed the computer readable medium storing the computer program performs the method comprising:

• determining for each connection a timing slack value and a number of timing paths using the connection;
• calculating a weight for each connection based on at least the timing slack value and the number of timing paths;
• comparing the connections with collapsing criteria in an order based on the weights of the connections;
• and
• collapsing connections that satisfy the collapsing criteria in the weight-based order,
• wherein the weight for each connection is calculated as follows:
• w=log(n+1)*s
• where n is the number of timing paths using the connection and s is the maximum timing slack value of the timing paths using the connection.

A computer-implemented method of selectively collapsing connections between a plurality of look up tables (LUTs) of a logic design, the method comprising:

• determining, via a computer system, for each connection a timing slack value and a number of timing paths using the connection;
• calculating a weight for each connection based on at least the timing slack value and the number of timing paths;
• comparing the connections with collapsing criteria in an order based on the weights of the connections;
• and
• collapsing connections that satisfy the collapsing criteria in the weight-based order,
• wherein the weight for each connection is calculated as follows:
• w=log(n+1)*s
• where n is the number of timing paths using the connection and s is the maximum timing slack value of the timing paths using the connection.

A computer-implemented method of selectively collapsing connections between a plurality of look up tables (LUTs) of a logic design, the method comprising:

• determining, via a computer system, for each connection a timing slack value and a number of timing paths using the connection;
• calculating a weight for each connection based on at least the timing slack value and the number of timing paths;
• comparing the connections with collapsing criteria in an order based on the weights of the connections;
• collapsing connections that satisfy the collapsing criteria in the weight-based order;
• associating each connection with one of a plurality of weight intervals based on the weight of the connection;
• and
• the order of comparing connections with the collapsing criteria is based on the associated weight interval, with the weight intervals being considered in order of decreasing weight.

A system comprising:

• a processor for executing a computer program;
• memory for storing the computer program;
• and
• a computer readable medium on which is stored the computer program which when executed by the processor in memory performs a method of selectively collapsing connections between a plurality of look up tables (LUTs) of a logic design, the method comprising:
• determining for each connection a timing slack value and a number of timing paths using the connection;
• calculating a weight for each connection based on at least the timing slack value and the number of timing paths;
• comparing the connections with collapsing criteria in an order based on the weights of the connections;
• and
• collapsing connections that satisfy the collapsing criteria in the weight-based order,
• wherein the weight for each connection is calculated as follows:
• w=log(n+1)*s
• where n is the number of timing paths using the connection and s is the maximum timing slack value of the timing paths using the connection.