FastRoute4-lefdef is an open-source global router.
The algorithm base is from FastRoute4.1, and the underlying infrastructure comes from Rsyn
The FastRoute4.1 version was received from yuexu@iastate.edu on June 15, 2019, with the BSD-3 open source license as given in the FastRoute website.
Rsyn version is based on commit 1087c918e4fa14db84fc3b4c91210db96b07bb4c and released under Apache License, Version 2.0 as given in its repository.
Any third party code such as Rsyn will clearly specify its license in each file and in this README. We ask contributors to seriously consider using the BSD-3 Licence.
- GCC compiler
- boost library
- cmake3.1
git clone --recursive https://github.com/The-OpenROAD-Project/FastRoute4-lefdef
cd FastRoute4-lefdef/
make PARALLEL=nthreads
NOTE: use PARALLEL=nthreads instead of -j nthreads
Your command line to run FastRoute4-lefdef should look like this:
./FRlefdef --no-gui --script /path/to/script.rsyn
You can find a script example in third_party/rsyn/support/fastroute/example.rsyn
The basic format of a script to run FastRoute is shown below:
open "generic" {
"lefFiles" : "example.lef",
"defFiles" : "example.def"
};
run "rsyn.fastRoute" {"outfile" : "example.guide", "adjustment" : 0.X, "maxRoutingLayer" : Y};
FastRoute has three main parameters. These are:
- outfile: name of the file with the generated guides
- adjustment: percentage reduction in capacity of each edge in the global routing gridgraph
- maxRoutingLayer: maximum (i.e., highest) routing layer available for FastRoute to use
If you need more than one LEF/DEF file, you can script for this case as:
open "generic" {
"lefFiles" : ["example1.lef", "example2.lef", ..., "exampleN.lef"],
"defFiles" : ["example1.def", "example2.def", ..., "exampleN.def"]
};
run "rsyn.fastRoute" {"outfile" : "example.guide", "adjustment" : 0.X, "maxRoutingLayer" : Y};
You can use either the absolute path or the relative path (relative to the script file) for LEF/DEF files.
-
Project programming language from C to C++
-
Added namespace “FastRoute” in all files
-
Code organization:
- License and folder hierarchy following Tim Ansell’s + Tom Spyru’s guidelines/suggestions
- Added licence header (as per Iowa website) in each file owned by them
- Added licence header (BSD-3) for new/created files
-
Code clean-up:
- Remove unused variables
- Declared not assigned
- Assigned not read
- Indentation/code-style for readability
- Remove unused variables
-
Setting maximum number of routing layers to 18
Previous setting: Maximum of 8 routing layers
Reason: Support for OpenRoad benchmarks -
Added auxiliary function to set layers preferred directions:
Previous setting: Hardcoded layers preferred directions
Reason: Set layers preferred directions according to each benchmark specification -
Added auxiliary function to get edges capacities
Previous setting: Cannot get the capacity of a specific edge
Reason: Access specific edge capacity to verify consistency in capacity adjustments -
Added auxiliary function to get all nets from FastRoute4 data structures
Previous setting: Cannot access nets from FastRoute4 data structures
Reason: Access nets added to FastRoute4 data structures in order to verify if all nets of the design were routed -
Increase maximum net name length
Previous setting: Nets added to FastRoute4 data structures can have at most 18 characters
Reason: Increasing net name limit to 200 characters, avoiding issues with net names of OpenRoad benchmarks -
Added flag in addAdjustments function allowing capacity increase
Previous setting: Capacities adjustments only decrease the original edges capacities
Reason: Allow edges capacities increase -
Removing net degree limitation for FastRoute4
Previous setting: Nets can have at most 1000 pins, or they will be ignored
Reason: Dynamically memory allocation for data structures dependents on the nets degree, allowing nets to have any degree -
Removing net degree limitation for Flute
Previous setting: Nets can have at most 1000 pins, or generates a segfault
Reason: Dynamically memory allocation for data structures dependents on the nets degree, allowing nets to have any degree
Implemented API to access FastRoute4 as a static library
- Declarations of the functions are in the following path:
FastRoute4-lefdef/third_party/fastroute/include/FastRoute.h - Implementation of the functions are in the following path:
FastRoute4-lefdef/third_party/fastroute/src/FastRoute.cpp
The following functions were implemented:
void setGridsandLayers(int x, int y, int nLayers);
This function initializes the grid and layer structures. Three parameters should be passed to this function:
- x : number of gcells in x;
- y : number of gcells in y;
- nLayers : number of layers.
void addVCapacity(int verticalCapacity, int layer);
This function adds a layer vertical capacity. Two parameters should be passed to this function:
- verticalCapacity : capacity of vertical edges in a layer;
- layer : layer number.
void addHCapacity(int horizontalCapacity, int layer);
This function adds a layer horizontal capacity. Two parameters should be passed to this function:
- horizontalCapacity : capacity of horizontal edges in a layer;
- layer : layer number.
void addMinWidth(int width, int layer);
This function adds wire minimum width for a specific layer. Two parameters should be passed to this function:
- width : minimum wire width value;
- layer : layer number.
void addMinSpacing(int spacing, int layer);
This function adds a layer minimum spacing. Two parameters should be passed to this function:
- spacing : minimum spacing value;
- layer : layer number.
void addViaSpacing(int spacing, int layer);
This function adds via minimum spacing for a specific layer. Two parameters should be passed to this function:
- spacing : via minimum spacing value;
- layer : layer number .
void setNumberNets(int nNets);
This function sets the total number of nets. One parameter should be passed to this function:
- nNets : total number of nets.
void setLowerLeft(int x, int y);
This function sets the lower left bounds. Two parameters should be passed to this function:
- x : lower left x position;
- y : lower left y position.
void setTileSize(int width, int height);
This function sets width and height of a gcell. Two parameters should be passed to this function:
- width : gcell width value;
- height : gcell height value.
void addNet(char *name, int netIdx, int nPins, int minWidth, PIN pins[]);
This function adds a net structure. Five parameters should be passed to this function:
- name : net name;
- netIdx : net index;
- nPins : number of pins of the net;
- minWidth : net minimum width;
- pins : vector containing the pins of the net.
void initEdges();
This function initializes grid edges; this function must be called right after all nets were added.
void setNumAdjustments(int nAdjustments);
This function sets the number of adjustments to be made. One parameter should be passed to this function:
- nAdjustments : number of adjustments.
void addAdjustment(long x1, long y1, int l1, long x2, long y2, int l2, int reducedCap, bool isReduce = true);
This function adds a capacity adjustment to a specific edge. Eight parameters should be passed to this function:
- x1 : x position of one of the gcells to which the edge belongs to;
- y1 : y position of the above gcell;
- l1 : layer number of the above gcell;
- x2 : x position of the second gcell to which the edge belongs to;
- y2 : y position of the above gcell;
- l2 : layer number of the above gcell;
- reducedCap : new edge capacity;
- isReduce : set to true if the capacity is going to be reduced, to false if it is going to be increased.
void initAuxVar();
This function initializes auxiliary variables; this function must be called right before the run function.
void run(std::vector<NET> &);
This function runs the fastroute algorithm, a vector of NETs should be passed as parameter; this is where the final result will be stored.
Copyright (c) 2019, Federal University of Rio Grande do Sul (UFRGS) All rights reserved.