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yosys - Man Page

Yosys Open SYnthesis Suite


yosys [options] <infile>


This manual page documents briefly the yosys command.

yosys is a program that synthesizes RTL to gate-level logic.


A summary of options is included below.


suppress printing of banner (copyright, disclaimer, version)


suppress printing of footer (log hash, version, timing statistics)


quiet operation. only write error message to console use this option twice to also quiet warning messages

-v <level>

print log headers up to level <level> to the console. (implies -q)


annotate all log messages with a time stamp


print more detailed timing stats at exit

-l logfile

write log messages to the specified file

-L logfile

like -l but open log file in line buffered mode

-o outfile

write the design to the specified file on exit

-b backend

use this backend for the output file specified on the command line

-f frontend

use the specified frontend for the input files on the command line


print the command list

-h command

print the help message for the specified command

-s scriptfile

execute the commands in the script file

-c tcl_scriptfile

execute the commands in the tcl script file (see 'help tcl' for details)

-p command

execute the commands

-m module_file

load the specified module (aka plugin)


enable tracing of core data structure changes. for debugging


will slightly randomize allocated pointer addresses. for debugging


will call abort() at the end of the script. for debugging

-D <header_id>[:<filename>]

dump the design when printing the specified log header to a file. yosys_dump_<header_id>.il is used as filename if none is specified. Use 'ALL' as <header_id> to dump at every header.

-W regex

if a warning message matches the regex, it is printed as regular message instead.

-e regex

if a warning message matches the regex, it is printed as error message instead and the tool terminates with a nonzero return code.


print version information and exit

-E depsfile

write a Makefile dependencies file with in- and output file names


The option -S is an alias for the "synth" command, a default script for transforming the Verilog input to a gate-level netlist. For example:

   yosys -o output.blif -S input.v


For more complex synthesis jobs it is recommended to use the read_* and write_* commands in a script file instead of specifying input and output files on the command line.

When no commands, script files or input files are specified on the command line, yosys automatically enters the interactive command mode. Use the 'help' command to get information on the individual commands.

See Also

berkeley-abc(1), yosys-config(1), yosys-filterlib(1)


yosys was written by Clifford Wolf <clifford@clifford.at>.

This manual page was written by Ruben Undheim <ruben.undheim@gmail.com>, for the Debian project (and may be used by others).

Referenced By

yosys-config(1), yosys-filterlib(1).

October 17, 2018