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Manual
Appendix
Command reference
YosysHQ Docs
Blog
Website
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Manual
Introduction
Basic principles
Approach
Implementation overview
Internal cell library
Programming Yosys extensions
The Verilog and AST frontends
Optimizations
Technology mapping
Memory mapping
Appendix
Auxiliary libraries
Auxiliary programs
RTLIL text representation
010: Converting Verilog to BLIF page
011: Interactive design investigation page
012: Converting Verilog to BTOR page
Literature references
Command reference
abc - use ABC for technology mapping
abc9 - use ABC9 for technology mapping
abc9_exe - use ABC9 for technology mapping
abc9_ops - helper functions for ABC9
add - add objects to the design
aigmap - map logic to and-inverter-graph circuit
alumacc - extract ALU and MACC cells
anlogic_eqn - Anlogic: Calculate equations for luts
anlogic_fixcarry - Anlogic: fix carry chain
assertpmux - adds asserts for parallel muxes
async2sync - convert async FF inputs to sync circuits
attrmap - renaming attributes
attrmvcp - move or copy attributes from wires to driving cells
autoname - automatically assign names to objects
blackbox - convert modules into blackbox modules
bmuxmap - transform $bmux cells to trees of $mux cells
booth - map $mul cells to Booth multipliers
bugpoint - minimize testcases
bwmuxmap - replace $bwmux cells with equivalent logic
cd - a shortcut for ‘select -module
’
check - check for obvious problems in the design
chformal - change formal constraints of the design
chparam - re-evaluate modules with new parameters
chtype - change type of cells in the design
clean - remove unused cells and wires
clean_zerowidth - clean zero-width connections from the design
clk2fflogic - convert clocked FFs to generic $ff cells
clkbufmap - insert clock buffers on clock networks
connect - create or remove connections
connect_rpc - connect to RPC frontend
connwrappers - match width of input-output port pairs
coolrunner2_fixup - insert necessary buffer cells for CoolRunner-II architecture
coolrunner2_sop - break $sop cells into ANDTERM/ORTERM cells
copy - copy modules in the design
cover - print code coverage counters
cutpoint - adds formal cut points to the design
debug - run command with debug log messages enabled
delete - delete objects in the design
deminout - demote inout ports to input or output
demuxmap - transform $demux cells to $eq + $mux cells
design - save, restore and reset current design
dffinit - set INIT param on FF cells
dfflegalize - convert FFs to types supported by the target
dfflibmap - technology mapping of flip-flops
dffunmap - unmap clock enable and synchronous reset from FFs
dft_tag - create tagging logic for data flow tracking
dump - print parts of the design in RTLIL format
echo - turning echoing back of commands on and off
edgetypes - list all types of edges in selection
efinix_fixcarry - Efinix: fix carry chain
equiv_add - add a $equiv cell
equiv_induct - proving $equiv cells using temporal induction
equiv_make - prepare a circuit for equivalence checking
equiv_mark - mark equivalence checking regions
equiv_miter - extract miter from equiv circuit
equiv_opt - prove equivalence for optimized circuit
equiv_purge - purge equivalence checking module
equiv_remove - remove $equiv cells
equiv_simple - try proving simple $equiv instances
equiv_status - print status of equivalent checking module
equiv_struct - structural equivalence checking
eval - evaluate the circuit given an input
exec - execute commands in the operating system shell
expose - convert internal signals to module ports
extract - find subcircuits and replace them with cells
extract_counter - Extract GreenPak4 counter cells
extract_fa - find and extract full/half adders
extract_reduce - converts gate chains into $reduce_* cells
extractinv - extract explicit inverter cells for invertible cell pins
flatten - flatten design
flowmap - pack LUTs with FlowMap
fmcombine - combine two instances of a cell into one
fminit - set init values/sequences for formal
formalff - prepare FFs for formal
freduce - perform functional reduction
fsm - extract and optimize finite state machines
fsm_detect - finding FSMs in design
fsm_expand - expand FSM cells by merging logic into it
fsm_export - exporting FSMs to KISS2 files
fsm_extract - extracting FSMs in design
fsm_info - print information on finite state machines
fsm_map - mapping FSMs to basic logic
fsm_opt - optimize finite state machines
fsm_recode - recoding finite state machines
fst2tb - generate testbench out of fst file
future - resolve future sampled value functions
yosys> help future
gatemate_foldinv - fold inverters into Gatemate LUT trees
glift - create GLIFT models and optimization problems
greenpak4_dffinv - merge greenpak4 inverters and DFF/latches
help - display help messages
hierarchy - check, expand and clean up design hierarchy
hilomap - technology mapping of constant hi- and/or lo-drivers
history - show last interactive commands
ice40_braminit - iCE40: perform SB_RAM40_4K initialization from file
ice40_dsp - iCE40: map multipliers
ice40_opt - iCE40: perform simple optimizations
ice40_wrapcarry - iCE40: wrap carries
insbuf - insert buffer cells for connected wires
iopadmap - technology mapping of i/o pads (or buffers)
jny - write design and metadata
json - write design in JSON format
lattice_gsr - Lattice: handle GSR
log - print text and log files
logger - set logger properties
ls - list modules or objects in modules
ltp - print longest topological path
lut2mux - convert $lut to $_MUX_
maccmap - mapping macc cells
memory - translate memories to basic cells
memory_bmux2rom - convert muxes to ROMs
memory_bram - map memories to block rams
memory_collect - creating multi-port memory cells
memory_dff - merge input/output DFFs into memory read ports
memory_libmap - map memories to cells
memory_map - translate multiport memories to basic cells
memory_memx - emulate vlog sim behavior for mem ports
memory_narrow - split up wide memory ports
memory_nordff - extract read port FFs from memories
memory_share - consolidate memory ports
memory_unpack - unpack multi-port memory cells
miter - automatically create a miter circuit
mutate - generate or apply design mutations
muxcover - cover trees of MUX cells with wider MUXes
muxpack - $mux/$pmux cascades to $pmux
nlutmap - map to LUTs of different sizes
onehot - optimize $eq cells for onehot signals
opt - perform simple optimizations
opt_clean - remove unused cells and wires
opt_demorgan - Optimize reductions with DeMorgan equivalents
opt_dff - perform DFF optimizations
opt_expr - perform const folding and simple expression rewriting
opt_ffinv - push inverters through FFs
opt_lut - optimize LUT cells
opt_lut_ins - discard unused LUT inputs
opt_mem - optimize memories
opt_mem_feedback - convert memory read-to-write port feedback paths to write enables
opt_mem_priority - remove priority relations between write ports that can never collide
opt_mem_widen - optimize memories where all ports are wide
opt_merge - consolidate identical cells
opt_muxtree - eliminate dead trees in multiplexer trees
opt_reduce - simplify large MUXes and AND/OR gates
opt_share - merge mutually exclusive cells of the same type that share an input signal
paramap - renaming cell parameters
peepopt - collection of peephole optimizers
plugin - load and list loaded plugins
pmux2shiftx - transform $pmux cells to $shiftx cells
pmuxtree - transform $pmux cells to trees of $mux cells
portlist - list (top-level) ports
prep - generic synthesis script
printattrs - print attributes of selected objects
proc - translate processes to netlists
proc_arst - detect asynchronous resets
proc_clean - remove empty parts of processes
proc_dff - extract flip-flops from processes
proc_dlatch - extract latches from processes
proc_init - convert initial block to init attributes
proc_memwr - extract memory writes from processes
proc_mux - convert decision trees to multiplexers
proc_prune - remove redundant assignments
proc_rmdead - eliminate dead trees in decision trees
proc_rom - convert switches to ROMs
qbfsat - solve a 2QBF-SAT problem in the circuit
ql_bram_merge - Infers QuickLogic k6n10f BRAM pairs that can operate independently
ql_bram_types - Change TDP36K type to subtypes
ql_dsp_io_regs - change types of QL_DSP2 depending on configuration
ql_dsp_macc - infer QuickLogic multiplier-accumulator DSP cells
ql_dsp_simd - merge QuickLogic K6N10f DSP pairs to operate in SIMD mode
qwp - quadratic wirelength placer
read - load HDL designs
read_aiger - read AIGER file
read_blif - read BLIF file
read_ilang - (deprecated) alias of read_rtlil
read_json - read JSON file
read_liberty - read cells from liberty file
read_rtlil - read modules from RTLIL file
read_verilog - read modules from Verilog file
recover_names - Execute a lossy mapping command and recover original netnames
rename - rename object in the design
rmports - remove module ports with no connections
sat - solve a SAT problem in the circuit
scatter - add additional intermediate nets
scc - detect strongly connected components (logic loops)
scratchpad - get/set values in the scratchpad
script - execute commands from file or wire
select - modify and view the list of selected objects
setattr - set/unset attributes on objects
setparam - set/unset parameters on objects
setundef - replace undef values with defined constants
share - perform sat-based resource sharing
shell - enter interactive command mode
show - generate schematics using graphviz
shregmap - map shift registers
sim - simulate the circuit
simplemap - mapping simple coarse-grain cells
splice - create explicit splicing cells
splitcells - split up multi-bit cells
splitnets - split up multi-bit nets
sta - perform static timing analysis
stat - print some statistics
submod - moving part of a module to a new submodule
supercover - add hi/lo cover cells for each wire bit
synth - generic synthesis script
synth_achronix - synthesis for Achronix Speedster22i FPGAs.
synth_anlogic - synthesis for Anlogic FPGAs
synth_coolrunner2 - synthesis for Xilinx Coolrunner-II CPLDs
synth_easic - synthesis for eASIC platform
synth_ecp5 - synthesis for ECP5 FPGAs
synth_efinix - synthesis for Efinix FPGAs
synth_fabulous - FABulous synthesis script
synth_gatemate - synthesis for Cologne Chip GateMate FPGAs
synth_gowin - synthesis for Gowin FPGAs
synth_greenpak4 - synthesis for GreenPAK4 FPGAs
synth_ice40 - synthesis for iCE40 FPGAs
synth_intel - synthesis for Intel (Altera) FPGAs.
synth_intel_alm - synthesis for ALM-based Intel (Altera) FPGAs.
synth_lattice - synthesis for Lattice FPGAs
synth_nexus - synthesis for Lattice Nexus FPGAs
synth_quicklogic - Synthesis for QuickLogic FPGAs
synth_sf2 - synthesis for SmartFusion2 and IGLOO2 FPGAs
synth_xilinx - synthesis for Xilinx FPGAs
synthprop - synthesize SVA properties
tcl - execute a TCL script file
techmap - generic technology mapper
tee - redirect command output to file
test_abcloop - automatically test handling of loops in abc command
test_autotb - generate simple test benches
test_cell - automatically test the implementation of a cell type
test_pmgen - test pass for pmgen
torder - print cells in topological order
trace - redirect command output to file
tribuf - infer tri-state buffers
uniquify - create unique copies of modules
verific - load Verilog and VHDL designs using Verific
verilog_defaults - set default options for read_verilog
verilog_defines - define and undefine verilog defines
viz - visualize data flow graph
wbflip - flip the whitebox attribute
wreduce - reduce the word size of operations if possible
write_aiger - write design to AIGER file
write_blif - write design to BLIF file
write_btor - write design to BTOR file
write_cxxrtl - convert design to C++ RTL simulation
write_edif - write design to EDIF netlist file
write_file - write a text to a file
write_firrtl - write design to a FIRRTL file
write_ilang - (deprecated) alias of write_rtlil
write_intersynth - write design to InterSynth netlist file
write_jny - generate design metadata
write_json - write design to a JSON file
write_rtlil - write design to RTLIL file
write_simplec - convert design to simple C code
write_smt2 - write design to SMT-LIBv2 file
write_smv - write design to SMV file
write_spice - write design to SPICE netlist file
write_table - write design as connectivity table
write_verilog - write design to Verilog file
write_xaiger - write design to XAIGER file
xilinx_dffopt - Xilinx: optimize FF control signal usage
xilinx_dsp - Xilinx: pack resources into DSPs
xilinx_srl - Xilinx shift register extraction
xprop - formal x propagation
zinit - add inverters so all FF are zero-initialized
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Command line reference
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future - resolve future sampled value functions
← fst2tb - generate testbench out of fst file
gatemate_foldinv - fold inverters into Gatemate LUT trees →
future - resolve future sampled value functions
¶
yosys>
help
future
¶
future
[options]
[selection]
← fst2tb - generate testbench out of fst file
gatemate_foldinv - fold inverters into Gatemate LUT trees →