OpenSTA is a gate level static timing verifier. As a stand-alone executable it can be used to verify the timing of a design using standard file formats.
- Verilog netlist
- Liberty library
- SDC timing constraints
- SDF delay annotation
- SPEF parasitics
OpenSTA uses a TCL command interpreter to read the design, specify timing constraints and print timing reports.
- Generated
- Latency
- Source latency (insertion delay)
- Uncertainty
- Propagated/Ideal
- Gated clock checks
- Multiple frequency clocks
- False path
- Multicycle path
- Min/Max path delay
- Exception points
- -from clock/pin/instance -through pin/net -to clock/pin/instance
- Edge specific exception points
- -rise_from/-fall_from, -rise_through/-fall_through, -rise_to/-fall_to
- Integrated Dartu/Menezes/Pileggi RC effective capacitance algorithm
- External delay calculator API
- Report timing checks -from, -through, -to, multiple paths to endpoint
- Report delay calculation
- Check timing setup
OpenSTA is architected to be easily bolted on to other tools as a timing engine. By using a network adapter, OpenSTA can access the host netlist data structures without duplicating them.
- Query based incremental update of delays, arrival and required times
- Simulator to propagate constants from constraints and netlist tie high/low
See doc/OpenSTA.pdf for complete documentiaton.
OpenSTA can be run as a Docker container or built as local executable with CMake.
- Install Docker on Windows, Mac or Linux.
- Navigate to the directory where you have the input files.
- Run OpenSTA as a binary using
docker run -it -v $(pwd):/data openroad/opensta
- From the interactive terminal, use OpenSTA commands. You can read input files from
/datadirectory inside the docker container (e.g.read_liberty /data/liberty.lib). You can use OpenSTA in non-interactive mode by passing a command file using the-fflag as follows.
docker run -it -v $(pwd):/data openroad/opensta -f /data/cmd_file
Note that the path after -f is the path inside container, not on the guest machine.
The build dependency versions are show below. Other versions may work, but these are the versions used for development.
from Ubuntu Xcode
18.04.1 10.1
cmake 3.9
clang 9.1.0 10.0.0
gcc 3.3.2 7.3.0
tcl 8.2 8.6 8.6.6
swig 1.3.28 3.0.12 3.0.12
bison 1.35 3.0.4 2.3
flex 2.5.4 2.6.4 2.5.35
These packages are optional:
libz 1.1.4 1.2.5 1.2.8
cudd 2.4.1 3.0.0
CUDD is a binary decision diageram (BDD) package that is used to improve conditional timing arc handling. OpenSTA does not require it to be installed. It is available here or here.
Note that the file hierarchy of the CUDD installation changed with version 3.0. Some changes to CMakeLists.txt are required to support older versions.
When building CUDD you may use the --prefix option to configure to
install in a location other than the default (/usr/local/lib).
cd $HOME/cudd-3.0.0
mkdir $HOME/cudd
./configure --prefix $HOME/cudd
make
make install
To not use CUDD specify CUDD=0.
Cmake looks for the CUDD library in CUDD/lib, CUDD/cudd/lib
and for the header in CUDD/include, CUDD/cudd/include.
# equivalent to -DCUDD=0
cmake ..
or
cmake .. -DCUDD=0
or
# look in ~/cudd/lib, ~/cudd/include
cmake .. -DCUDD=$HOME/cudd
or
# look in /usr/local/lib/cudd, /usr/local/include/cudd
cmake .. -DCUDD=/usr/local
The Zlib library is an optional. If CMake finds libz, OpenSTA can read Verilog, SDF, SPF, and SPEF files compressed with gzip.
Use the following commands to checkout the git repository and build the OpenSTA library and excutable.
git clone https://xp-dev.com/git/opensta
cd opensta
mkdir build
cd build
cmake ..
make
The default build type is release to compile optimized code.
The resulting executable is in app/sta.
The library without a main() procedure is app/libSTA.a.
Optional CMake variables passed as -D= arguments to CMake are show below.
CMAKE_BUILD_TYPE DEBUG|RELEASE
CMAKE_CXX_FLAGS - additional compiler flags
TCL_LIB - path to tcl library
TCL_HEADER - path to tcl.h
CUDD - path to cudd installation
ZLIB_ROOT - path to zlib
CMAKE_INSTALL_PREFIX
If TCL_LIB is specified the CMake script will attempt to locate the
header from the library path.
The default install directory is /usr/local.
To install in a different directory with CMake use:
cmake .. -DCMAKE_INSTALL_PREFIX=<prefix_path>
Alternatively, you can use the DESTDIR variable with make.
make DESTDIR=<prefix_path> install
If you make changes to CMakeLists.txt you may need to clean out
existing CMake cached variable values by deleting all of the
files in the build directory.
Use a .bat file to start a cygwin shell that has its path set to support the Microcruft cl compiler by calling the vsvars32.bat script from the Visual C++ installation.
tcsh-startup.bat
@echo off
call "c:\Microsoft Visual Studio 9.0\Common7\Tools\vsvars.bat"
set path=c:\cygwin\bin;%PATH%
c:\cygwin\bin\tcsh
CMake is supposedly more compatible with the windoz environment so you may have better luck wih it.
Cmake and build from the shell. Note that tcl and zlib must be built with the Visual C++ compiler to link to the sta libraries.
mkdir build cd build cmakd .. make ...
Good luck and don't bother me with windoz specific issues. I am happy to say I haven't owned a windoz machine in 20 years.
-
James Cherry
-
William Scott authored the arnoldi delay calculator at Blaze, Inc which was subsequently licensed to Nefelus, Inc that has graciously contributed it to OpenSTA.
OpenSTA, Static Timing Analyzer Copyright (c) 2019, Parallax Software, Inc.
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.