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CHANGELOG
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List of major changes and improvements between releases
=======================================================
Yosys 0.49 .. Yosys 0.50-dev
--------------------------
Yosys 0.48 .. Yosys 0.49
--------------------------
* Various
- "$scopeinfo" cells are now part of JSON export by default.
- Added option to specify hierarchical separator for "flatten".
- Improved "wreduce" to handle more cases of operator size reduction.
- Updated hashing interface, see docs/source/yosys_internals/hashing.rst
for breaking API changes.
* New commands and options
- Added "-noscopeinfo" option to "json" and "write_json" pass.
Yosys 0.47 .. Yosys 0.48
--------------------------
* Various
- Removed "read_ilang" deprecated pass.
- Enhanced boxing features in the experimental "abc_new" command.
- Added new Tcl methods for design inspection.
- Added clock enable inference to "dfflibmap".
- Added a Han-Carlson and Sklansky option for $lcu mapping.
* New commands and options
- Added "-nopeepopt" option to "clk2fflogic" pass.
- Added "-liberty" and "-dont_use" options to "clockgate" pass.
- Added "-ignore_buses" option to "read_liberty" pass.
- Added "-dont_map" option to "techmap" pass.
- Added "-selected" option to "write_json" pass.
- Added "wrapcell" command for creating wrapper modules
around selected cells.
- Added "portarcs" command for deriving propagation timing arcs.
- Added "setenv" command for setting environment variables.
* Gowin support
- Added "-family" option to "synth_gowin" pass.
- Cell definitions split by family.
* Verific support
- Improved blackbox support.
Yosys 0.46 .. Yosys 0.47
--------------------------
* Various
- Added cxxopts library for handling command line arguments.
- Added docs generation from cells help output.
* New commands and options
- Added "-json" option to "synth_xilinx" pass.
- Added "-derive_luts" option to "cellmatch" pass.
- Added "t:@<name>" syntax to "select" pass.
- Added "-list-mod" option to "select" pass.
- Removed deprecated "qwp" pass.
* Verific support
- Initial state handling for VHDL assertions.
Yosys 0.45 .. Yosys 0.46
--------------------------
* Various
- Added new "functional backend" infrastructure with three example
backends (C++, SMTLIB and Rosette).
- Added new coarse-grain buffer cell type "$buf" to RTLIL.
- Added "-y" command line option to execute a Python script with
libyosys available as a built-in module.
- Added support for casting to type in Verilog frontend.
* New commands and options
- Added "clockgate" pass for automatic clock gating cell insertion.
- Added "bufnorm" experimental pass to convert design into
buffered-normalized form.
- Added experimental "aiger2" and "xaiger2" backends, and an
experimental "abc_new" command
- Added "-force-detailed-loop-check" option to "check" pass.
- Added "-unit_delay" option to "read_liberty" pass.
* Verific support
- Added left and right bound properties to wires when using
specific VHDL types.
Yosys 0.44 .. Yosys 0.45
--------------------------
* Various
- Added cell types help messages.
* New back-ends
- Added initial NG-Ultra support. ( synth_nanoxplore )
Yosys 0.43 .. Yosys 0.44
--------------------------
* Various
- Added ENABLE_LTO compile option to enable link time
optimizations.
- Build support for Haiku OS.
* New commands and options
- Added "keep_hierarchy" pass to add attribute with
same name to modules based on cost.
- Added options "-noopt","-bloat" and "-check_cost" to
"test_cell" pass.
* New back-ends
- Added initial PolarFire support. ( synth_microchip )
Yosys 0.42 .. Yosys 0.43
--------------------------
* Various
- C++ compiler with C++17 support is required.
- Support for IO liberty files for verification.
- Limit padding from shiftadd for "peepopt" pass.
* Verific support
- Support building Yosys with various Verific library
configurations. Can be built now without YosysHQ
specific patch and extension library.
Yosys 0.41 .. Yosys 0.42
--------------------------
* New commands and options
- Added "box_derive" pass to derive box modules.
- Added option "assert-mod-count" to "select" pass.
- Added option "-header","-push" and "-pop" to "log" pass.
* Intel support
- Dropped Quartus support in "synth_intel_alm" pass.
Yosys 0.40 .. Yosys 0.41
--------------------------
* New commands and options
- Added "cellmatch" pass for picking out standard cells automatically.
* Various
- Extended the experimental incremental JSON API to allow arbitrary
smtlib subexpressions.
- Added support for using ABCs library merging when providing multiple
liberty files.
* Verific support
- Expose library name as module attribute.
Yosys 0.39 .. Yosys 0.40
--------------------------
* New commands and options
- Added option "-vhdl2019" to "read" and "verific" pass.
* Various
- Major documentation overhaul.
- Added port statistics to "stat" command.
- Added new formatting features to cxxrtl backend.
* Verific support
- Added better support for VHDL constants import.
- Added support for VHDL 2009.
Yosys 0.38 .. Yosys 0.39
--------------------------
* New commands and options
- Added option "-extra-map" to "synth" pass.
- Added option "-dont_use" to "dfflibmap" pass.
- Added option "-href" to "show" command.
- Added option "-noscopeinfo" to "flatten" pass.
- Added option "-scopename" to "flatten" pass.
* SystemVerilog
- Added support for packed multidimensional arrays.
* Various
- Added "$scopeinfo" cells to preserve information about
the hierarchy during flattening.
- Added sequential area output to "stat -liberty".
- Added ability to record/replay diagnostics in cxxrtl backend.
* Verific support
- Added attributes to module instantiation.
Yosys 0.37 .. Yosys 0.38
--------------------------
* New commands and options
- Added option "-tech" to "opt_lut" pass.
- Added option "-nokeep_prints" to "hierarchy" pass.
- Added option "-nolower" to "async2sync" and "clk2fflogic" pass.
- Added option "-lower" to "chformal" pass.
* Various
- Added $check cell to represent assertions with messages.
- Allow capturing $print cell output in CXXRTL.
- Added API to overwrite existing pass from plugin.
- Follow the XDG Base Directory Specification for storing history files.
- Without a known top module, derive all deferred modules (hierarchy pass).
- Detect and error out on combinational loops in write_aiger.
* Verific support
- Added option "-no-split-complex-ports" to "verific -import".
Yosys 0.36 .. Yosys 0.37
--------------------------
* New commands and options
- Added option "-nodisplay" to read_verilog.
* SystemVerilog
- Correct hierarchical path names for structs and unions.
* Various
- Print hierarchy for failed assertions in "sim" pass.
- Add "--present-only" option to "yosys-witness" to omit unused signals.
- Implement a generic record/replay interface for CXXRTL.
- Improved readability of emitted code with "write_verilog".
Yosys 0.35 .. Yosys 0.36
--------------------------
* New commands and options
- Added option "--" to pass arguments down to tcl when using -c option.
- Added ability on MacOS and Windows to pass options after arguments on cli.
- Added option "-cmp2softlogic" to synth_lattice.
- Added option "-lowpower" to "booth" pass.
* QuickLogic support
- Added "K6N10f" support.
- Added "-nodsp", "-nocarry", "-nobram" and "-bramtypes" options to
"synth_quicklogic" pass.
- Added "ql_bram_merge" pass to merge 18K BRAM cells into TDP36K.
- Added "ql_bram_types" pass to change TDP36K depending on configuration.
- Added "ql_dsp_io_regs" pass to update QL_DSP2 depending on configuration.
- Added "ql_dsp_macc" pass to infer multiplier-accumulator DSP cells.
- Added "ql_dsp_simd" pass to merge DSP pairs to operate in SIMD mode.
* ECP5,iCE40 and Gowin support
- Enabled abc9 by default, added "-noabc9" option to disable.
* MachXO3 support
- Quality of results improvements.
- Enabled "booth" pass by default for it in "synth_lattice".
* Various
- Improved "peepopt" by adding shiftadd pattern support.
- Added "--incremental" mode to smtbmc.
Yosys 0.34 .. Yosys 0.35
--------------------------
* Various
- Improvements on "peepopt" shiftmul matcher.
- Improvements on "ram_style" attributes handling.
* Verific support
- Improved static elaboration for VHDL and mixed HDL designs.
- Expose "hdlname" attribute with original module name.
- Expose "architecture" attribute with VHDL architecture name.
Yosys 0.33 .. Yosys 0.34
--------------------------
* New commands and options
- Added option "-assert" to "sim" pass.
- Added option "-noinitstate" to "sim" pass.
- Added option "-dont_use" to "abc" pass.
- Added "dft_tag" pass to create tagging logic for data flow tracking.
- Added "future" pass to resolve future sampled value functions.
- Added "booth" pass to map $mul cells to Booth multipliers.
- Added option "-booth" to "synth" pass.
* SystemVerilog
- Added support for assignments within expressions, e.g., `x[y++] = z;` or
`x = (y *= 2) - 1;`.
* Verific support
- "src" attribute contain full location info.
- module parameters are kept after import.
- accurate access order semantics in memory inference.
- better "bind" support for mixed language projects.
* Various
- "show" command displays dot instead of box for wire aliases.
Yosys 0.32 .. Yosys 0.33
--------------------------
* Various
- Added "$print" cell, produced by "$display" and "$write"
Verilog tasks.
- Added "$print" cell handling in CXXRTL.
* Lattice FPGA support
- Added generic "synth_lattice" pass (for now MachXO2/XO3/XO3D)
- Removed "synth_machxo2" pass
- Pass "ecp5_gsr" renamed to "lattice_gsr"
- "synth_machxo2" equivalent is "synth_lattice -family xo2"
Yosys 0.31 .. Yosys 0.32
--------------------------
* Verific support
- Added sub option "-lib" to reading commands for VHDL and
SystemVerilog, that will later import all units/modules from
marked files as blackboxes.
* Various
- Added support for $lt, $le, $gt, $ge to the code generating AIGs.
Yosys 0.30 .. Yosys 0.31
--------------------------
* New commands and options
- Added option "-lsbidx" to "write_edif" pass.
* Various
- Added support for $divfloor operator to cxxrtl backend.
- dfflegalize: allow setting mince and minsrst args from scratchpad.
Yosys 0.29 .. Yosys 0.30
--------------------------
* New commands and options
- Added "recover_names" pass to recover names post-mapping.
* Gowin support
- Added remaining primitives blackboxes.
* Various
- "show -colorattr" will now color the cells, wires, and
connection arrows.
- "show -viewer none" will not execute viewer.
Yosys 0.28 .. Yosys 0.29
--------------------------
* New commands and options
- Added "synthprop" pass for synthesizable properties.
* Verific support
- Handle conditions on clocked concurrent assertions in unclocked
procedural contexts.
* Verilog
- Fix const eval of unbased unsized constants.
- Handling of attributes for struct / union variables.
Yosys 0.27 .. Yosys 0.28
--------------------------
* Verilog
- Out of bounds checking for struct/union members.
* Verific support
- Fix enum_values support and signed attribute values.
* ECP5 support
- Added "synth_ecp5 -iopad"
* MachXO2 support
- Added "synth_machxo2 -ccu2"
Yosys 0.26 .. Yosys 0.27
--------------------------
* New commands and options
- Added option "-make_assert" to "equiv_make" pass.
- Added option "-coverenable" to "chformal" pass.
* Verilog
- Resolve package types in interfaces.
- Handle range offsets in packed arrays within packed structs.
- Support for data and array queries on struct/union item expressions.
* GateMate support
- Enable register initialization.
Yosys 0.25 .. Yosys 0.26
--------------------------
* New commands and options
- Added "bwmuxmap" pass to replace $bwmux cells with equivalent logic.
- Added "xprop" experimental pass for formal x propagation.
- Added "splitcells" pass to split up multi-bit cells.
- Added "viz" pass to visualize data flow graph.
- Added option "-make_cover" to "miter" pass.
- Added option "-noparallelcase" to "write_verilog" pass.
- Added option "-chain" to "insbuf" pass.
- Added options "-hierarchy" and "-assume" to "formalff" pass.
- Added options "-append" and "-summary" to "sim" pass.
- Added option "-ywmap" to "write_btor" pass.
- Added option "-ignore-self-reset" to "fsm_detect" pass.
* Verilog
- Support for struct members of union type.
- Support for struct member package types.
* Various
- Added Yosys witness (.yw) cosimulation.
- GCC 4.8 is deprecated, compiler with full C++11 support is required.
Yosys 0.24 .. Yosys 0.25
--------------------------
* Verific support
- Respect "noblackbox" attribute for modules.
* Various
- Documentation is hosted at https://yosyshq.readthedocs.io/projects/yosys/en/latest/
Yosys 0.23 .. Yosys 0.24
--------------------------
* New commands and options
- Added option "-set-def-formal" to "sat" pass.
- Added option "-s" to "tee" command.
* Verilog
- Support for module-scoped identifiers referring to tasks and functions.
- Support for arrays with swapped ranges within structs.
* Verific support
- Support for importing verilog configurations per name.
- "verific -set-XXXXX" commands are now able to set severity to all messages
of certain type (errors, warnings, infos and comments)
* Various
- TCL shell support (use "yosys -C")
- Added FABulous eFPGA frontend
Yosys 0.22 .. Yosys 0.23
--------------------------
* New commands and options
- Added option "-cross" to "miter" pass.
- Added option "-nocheck" to "equiv_opt" pass.
* Formal Verification
- yosys-smtbmc: Added "--detect-loops" option for checking if states are
unique in temporal induction counter examples.
* Verific support
- Added support for reading Liberty files using Verific library.
(Optinally enabled with ENABLE_VERIFIC_LIBERTY)
- Added option "-cells" to "verific -import" enabling import of
all cells from verific design.
* Various
- MinGW build (Windows) plugin support.
- Added YOSYS_ABORT_ON_LOG_ERROR environment variable for debugging.
Setting it to 1 causes abort() to be called when Yosys terminates with an
error message.
Yosys 0.21 .. Yosys 0.22
--------------------------
* Verific support
- Added support for here-document for "verific" command (for reading
source files).
- Added support for reading EDIF files using Verific library.
(Optinally enabled with ENABLE_VERIFIC_EDIF)
* Various
- Added tech specific utilization to "stat" json.
Yosys 0.20 .. Yosys 0.21
--------------------------
* New commands and options
- Added "formalff" pass - transforms FFs for formal verification
- Added option "-formal" to "memory_map" pass
- Added option "-witness" to "rename" - give public names to all signals
present in yosys witness traces
- Added option "-hdlname" to "sim" pass - preserves hiearachy when writing
simulation output for a flattened design
- Addded option "-scramble-name" to "rename" pass
* Formal Verification
- Added $anyinit cell to directly represent FFs with an unconstrained
initialization value. These can be generated by the new formalff pass.
- New JSON based yosys witness format for formal verification traces.
- yosys-smtbmc: Reading and writing of yosys witness traces.
- write_smt2: Emit inline metadata to support yosys witness trace.
- yosys-witness is a new tool to inspect and convert yosys witness traces.
- write_aiger: Option to write a map file for yosys witness trace
conversion.
- yosys-witness: Conversion from and to AIGER witness traces.
* Verific support
- Filename re-writing support for "verific" pass.
* Various
- ABC performance improvements
- Filename re-writing added for "show -lib".
* SmartFusion2 support
- Added $alu support
- Added SYSRESET and XTLOSC cells
- Compatible now with LiberoSoc flow
Yosys 0.19 .. Yosys 0.20
--------------------------
* New commands and options
- Added option "-wb" to "read_liberty" pass
* Various
- Added support for $modfloor operator to cxxrtl backend
- Support build on OpenBSD
- Fixed smt2 backend use of $shift/$shiftx with negative shift amounts,
which affects bit/part-select assignments with a dynamic index. Shift
operators were not affected.
* Verific support
- Proper import of port ranges into Yosys, may result in reversed
bit-order of top-level ports for some synthesis flows.
Yosys 0.18 .. Yosys 0.19
--------------------------
* New commands and options
- Added option "-rom-only" to "memory_libmap" pass
- Added option "-smtcheck" to "hierarchy" pass
- Added option "-keepdc" to "memory_libmap" pass
- Added option "-suffix" to "rename" pass
- Added "gatemate_foldinv" pass
* Formal Verification
- Added support for $pos cell in btor backend
- Added the "smtlib2_module" and "smtlib2_comb_expr" attributes
* GateMate support
- Added LUT tree mapping
* Verific support
- Added option "-pp" to "verific -import"
Yosys 0.17 .. Yosys 0.18
--------------------------
* Various
- Migrated most flows to use memory_libmap based memory inference
* New commands and options
- Added "memory_libmap" pass
- Added "memory_bmux2rom" pass - converts muxes to ROMs
- Added "memory_dff -no-rw-check"
- Added "opt_ffinv" pass - push inverters through FFs
- Added "proc_rom" pass - convert switches to ROMs
- Added "proc -norom" option - will omit the proc_rom pass
- Added option "-no-rw-check" to synth passes
- Added "synth_ice40 -spram" option for automatic inference of SB_SPRAM256KA
- Added options "-nobram" and "-nolutram" to synth_machxo2 pass
* Formal Verification
- Fixed the signedness of $past's return value to be the same as the
argument's instead of always unsigned.
* Verilog
- Fixed an issue where simplifying case statements by removing unreachable
cases could result in the wrong signedness being used for comparison with
the remaining cases
- Fixed size and signedness computation for expressions containing array
querying functions
- Fixed size and signedness computation of functions used in ternary
expressions or case item expressions
* Verific support
- Proper file location for readmem commands
- Added "-vlog-libext" option to specify search extension for libraries
Yosys 0.16 .. Yosys 0.17
--------------------------
* New commands and options
- Added "write_jny" ( JSON netlist metadata format )
- Added "tribuf -formal"
* SystemVerilog
- Fixed automatic `nosync` inference for local variables in `always_comb`
procedures not applying to nested blocks and blocks in functions
Yosys 0.15 .. Yosys 0.16
--------------------------
* Various
- Added BTOR2 witness file co-simulation.
- Simulation calls external vcd2fst for VCD conversion.
- Added fst2tb pass - generates testbench for the circuit using
the given top-level module and simulus signal from FST file.
- yosys-smtbmc: Option to keep going after failed assertions in BMC mode
* Verific support
- Import modules in alphabetic (reproducable) order.
Yosys 0.14 .. Yosys 0.15
--------------------------
* Various
- clk2fflogic: nice names for autogenerated signals
- simulation include support for all flip-flop types.
- Added AIGER witness file co-simulation.
* Verilog
- Fixed evaluation of constant functions with variables or arguments with
reversed dimensions
- Fixed elaboration of dynamic range assignments where the vector is
reversed or is not zero-indexed
- Added frontend support for time scale delay values (e.g., `#1ns`)
* SystemVerilog
- Added support for accessing whole sub-structures in expressions
* New commands and options
- Added glift command, used to create gate-level information flow tracking
(GLIFT) models by the "constructive mapping" approach
* Verific support
- Ability to override default parser mode for verific -f command.
Yosys 0.13 .. Yosys 0.14
--------------------------
* Various
- Added $bmux and $demux cells and related optimization patterns.
* New commands and options
- Added "bmuxmap" and "dmuxmap" passes
- Added "-fst" option to "sim" pass for writing FST files
- Added "-r", "-scope", "-start", "-stop", "-at", "-sim", "-sim-gate",
"-sim-gold" options to "sim" pass for co-simulation
* Anlogic support
- Added support for BRAMs
Yosys 0.12 .. Yosys 0.13
--------------------------
* Various
- Use "read" command to parse HDL files from Yosys command-line
- Added "yosys -r <topmodule>" command line option
- write_verilog: dump zero width sigspecs correctly
* SystemVerilog
- Fixed regression preventing the use array querying functions in case
expressions and case item expressions
- Fixed static size casts inadvertently limiting the result width of binary
operations
- Fixed static size casts ignoring expression signedness
- Fixed static size casts not extending unbased unsized literals
- Added automatic `nosync` inference for local variables in `always_comb`
procedures which are always assigned before they are used to avoid errant
latch inference
* New commands and options
- Added "clean_zerowidth" pass
* Verific support
- Add YOSYS to the implicitly defined verilog macros in verific
Yosys 0.11 .. Yosys 0.12
--------------------------
* Various
- Added iopadmap native support for negative-polarity output enable
- ABC update
* SystemVerilog
- Support parameters using struct as a wiretype
* New commands and options
- Added "-genlib" option to "abc" pass
- Added "sta" very crude static timing analysis pass
* Verific support
- Fixed memory block size in import
* New back-ends
- Added support for GateMate FPGA from Cologne Chip AG
* Intel ALM support
- Added preliminary Arria V support
Yosys 0.10 .. Yosys 0.11
--------------------------
* Various
- Added $aldff and $aldffe (flip-flops with async load) cells
* SystemVerilog
- Fixed an issue which prevented writing directly to a memory word via a
connection to an output port
- Fixed an issue which prevented unbased unsized literals (e.g., `'1`) from
filling the width of a cell input
- Fixed an issue where connecting a slice covering the entirety of a signed
signal to a cell input would cause a failed assertion
* Verific support
- Importer support for {PRIM,WIDE_OPER}_DFF
- Importer support for PRIM_BUFIF1
- Option to use Verific without VHDL support
- Importer support for {PRIM,WIDE_OPER}_DLATCH{,RS}
- Added -cfg option for getting/setting Verific runtime flags
Yosys 0.9 .. Yosys 0.10
--------------------------
* Various
- Added automatic gzip decompression for frontends
- Added $_NMUX_ cell type
- Added automatic gzip compression (based on filename extension) for backends
- Improve attribute and parameter encoding in JSON to avoid ambiguities between
bit vectors and strings containing [01xz]*
- Improvements in pmgen: subpattern and recursive matches
- Support explicit FIRRTL properties
- Improvements in pmgen: slices, choices, define, generate
- Added "_TECHMAP_WIREINIT_*_" parameter and "_TECHMAP_REMOVEINIT_*_" wire for "techmap" pass
- Added +/mul2dsp.v for decomposing wide multipliers to custom-sized ones
- Added new frontend: rpc
- Added --version and -version as aliases for -V
- Improve yosys-smtbmc "solver not found" handling
- Improved support of $readmem[hb] Memory Content File inclusion
- Added CXXRTL backend
- Use YosysHQ/abc instead of upstream berkeley-abc/abc
- Added WASI platform support.
- Added extmodule support to firrtl backend
- Added $divfloor and $modfloor cells
- Added $adffe, $dffsre, $sdff, $sdffe, $sdffce, $adlatch cells
- Added "_TECHMAP_CELLNAME_" parameter for "techmap" pass
- Added firrtl backend support for generic parameters in blackbox components
- Added $meminit_v2 cells (with support for write mask)
- Added $mem_v2, $memrd_v2, $memwr_v2, with the following features:
- write priority masks, per write/write port pair
- transparency and undefined collision behavior masks, per read/write port pair
- read port reset and initialization
- wide ports (accessing a naturally aligned power-of-two number of memory cells)
* New commands and options
- Added "write_xaiger" backend
- Added "read_xaiger"
- Added "abc9" pass for timing-aware techmapping (experimental, FPGA only)
- Added "synth -abc9" (experimental)
- Added "script -scriptwire"
- Added "clkbufmap" pass
- Added "extractinv" pass and "invertible_pin" attribute
- Added "proc_clean -quiet"
- Added "proc_prune" pass
- Added "stat -tech cmos"
- Added "opt_share" pass, run as part of "opt -full"
- Added "-match-init" option to "dff2dffs" pass
- Added "equiv_opt -multiclock"
- Added "techmap_autopurge" support to techmap
- Added "add -mod <modname[s]>"
- Added "paramap" pass
- Added "portlist" command
- Added "check -mapped"
- Added "check -allow-tbuf"
- Added "autoname" pass
- Added "write_verilog -extmem"
- Added "opt_mem" pass
- Added "scratchpad" pass
- Added "fminit" pass
- Added "opt_lut_ins" pass
- Added "logger" pass
- Added "show -nobg"
- Added "exec" command
- Added "design -delete"
- Added "design -push-copy"
- Added "qbfsat" command
- Added "select -unset"
- Added "dfflegalize" pass
- Removed "opt_expr -clkinv" option, made it the default
- Added "proc -nomux
- Merged "dffsr2dff", "opt_rmdff", "dff2dffe", "dff2dffs", "peepopt.dffmux" passes into a new "opt_dff" pass
* SystemVerilog
- Added checking of always block types (always_comb, always_latch and always_ff)
- Added support for wildcard port connections (.*)
- Added support for enum typedefs
- Added support for structs and packed unions.
- Allow constant function calls in for loops and generate if and case
- Added support for static cast
- Added support for logic typed parameters
- Fixed generate scoping issues
- Added support for real-valued parameters
- Allow localparams in constant functions
- Module name scope support
- Support recursive functions using ternary expressions
- Extended support for integer types
- Support for parameters without default values
- Allow globals in one file to depend on globals in another
- Added support for: *=, /=, %=, <<=, >>=, <<<=, >>>=
- Added support for parsing the 'bind' construct
- support declaration in procedural for initialization
- support declaration in generate for initialization
- Support wand and wor of data types
* Verific support
- Added "verific -L"
- Add Verific SVA support for "always" properties
- Add Verific support for SVA nexttime properties
- Improve handling of verific primitives in "verific -import -V" mode
- Import attributes for wires
- Support VHDL enums
- Added support for command files
* New back-ends
- Added initial EFINIX support
- Added Intel ALM: alternative synthesis for Intel FPGAs
- Added initial Nexus support
- Added initial MachXO2 support
- Added initial QuickLogic PolarPro 3 support
* ECP5 support
- Renamed labels/options in synth_ecp5 (e.g. dram -> map_lutram; -nodram -> -nolutram)
- Added "synth_ecp5 -abc9" (experimental)
- Added "synth_ecp5 -nowidelut"
- "synth_ecp5" to now infer DSP blocks (-nodsp to disable, experimental)
* iCE40 support
- Added "synth_ice40 -abc9" (experimental)
- Added "synth_ice40 -device"
- Renamed labels/options in synth_ice40 (e.g. dram -> map_lutram; -nodram -> -nolutram)
- Added "ice40_wrapcarry" to encapsulate SB_LUT+SB_CARRY pairs for techmapping
- Removed "ice40_unlut"
- Added "ice40_dsp" for Lattice iCE40 DSP packing
- "synth_ice40 -dsp" to infer DSP blocks
* Xilinx support
- Added "synth_xilinx -abc9" (experimental)
- Added "synth_xilinx -nocarry"
- Added "synth_xilinx -nowidelut"
- "synth_xilinx" to now infer wide multiplexers (-widemux <min> to enable)
- Renamed labels/options in synth_xilinx (e.g. dram -> map_lutram; -nodram -> -nolutram)
- Added "synth_xilinx -family xc6s" for Spartan 6 support (experimental)
- Added "synth_xilinx -ise" (experimental)
- Added "synth_xilinx -iopad"
- "synth_xilinx" now automatically inserts clock buffers (add -noclkbuf to disable)
- Added "xilinx_srl" for Xilinx shift register extraction
- Removed "shregmap -tech xilinx" (superseded by "xilinx_srl")
- Added "xilinx_dsp" for Xilinx DSP packing
- "synth_xilinx" to now infer DSP blocks (-nodsp to disable)
- Added latch support to synth_xilinx
- Added support for flip-flops with synchronous reset to synth_xilinx
- Added support for flip-flops with reset and enable to synth_xilinx
- Added "xilinx_dffopt" pass
- Added "synth_xilinx -dff"
* Intel support
- Renamed labels in synth_intel (e.g. bram -> map_bram)
- synth_intel: cyclone10 -> cyclone10lp, a10gx -> arria10gx
- Added "intel_alm -abc9" (experimental)
* CoolRunner2 support
- Separate and improve buffer cell insertion pass
- Use extract_counter to optimize counters
Yosys 0.8 .. Yosys 0.9
----------------------
* Various
- Many bugfixes and small improvements
- Added support for SystemVerilog interfaces and modports
- Added "write_edif -attrprop"
- Added "opt_lut" pass
- Added "gate2lut.v" techmap rule
- Added "rename -src"
- Added "equiv_opt" pass
- Added "flowmap" LUT mapping pass
- Added "rename -wire" to rename cells based on the wires they drive
- Added "bugpoint" for creating minimised testcases
- Added "write_edif -gndvccy"
- "write_verilog" to escape Verilog keywords
- Fixed sign handling of real constants
- "write_verilog" to write initial statement for initial flop state
- Added pmgen pattern matcher generator
- Fixed opt_rmdff handling of $_DFFSR_???_ and $_DLATCHSR_???_
- Added "setundef -params" to replace undefined cell parameters
- Renamed "yosys -D" to "yosys -U", added "yosys -D" to set Verilog defines
- Fixed handling of defparam when default_nettype is none
- Fixed "wreduce" flipflop handling
- Fixed FIRRTL to Verilog process instance subfield assignment
- Added "write_verilog -siminit"
- Several fixes and improvements for mem2reg memories
- Fixed handling of task output ports in clocked always blocks
- Improved handling of and-with-1 and or-with-0 in "opt_expr"
- Added "read_aiger" frontend
- Added "mutate" pass
- Added "hdlname" attribute
- Added "rename -output"
- Added "read_ilang -lib"
- Improved "proc" full_case detection and handling
- Added "whitebox" and "lib_whitebox" attributes
- Added "read_verilog -nowb", "flatten -wb" and "wbflip"
- Added Python bindings and support for Python plug-ins
- Added "pmux2shiftx"
- Added log_debug framework for reduced default verbosity
- Improved "opt_expr" and "opt_clean" handling of (partially) undriven and/or unused wires
- Added "peepopt" peephole optimisation pass using pmgen
- Added approximate support for SystemVerilog "var" keyword
- Added parsing of "specify" blocks into $specrule and $specify[23]
- Added support for attributes on parameters and localparams
- Added support for parsing attributes on port connections
- Added "wreduce -keepdc"
- Added support for optimising $dffe and $_DFFE_* cells in "opt_rmdff"
- Added Verilog wand/wor wire type support
- Added support for elaboration system tasks
- Added "muxcover -mux{4,8,16}=<cost>"
- Added "muxcover -dmux=<cost>"
- Added "muxcover -nopartial"
- Added "muxpack" pass
- Added "pmux2shiftx -norange"
- Added support for "~" in filename parsing
- Added "read_verilog -pwires" feature to turn parameters into wires
- Fixed sign extension of unsized constants with 'bx and 'bz MSB
- Fixed genvar to be a signed type
- Added support for attributes on case rules
- Added "upto" and "offset" to JSON frontend and backend
- Several liberty file parser improvements
- Fixed handling of more complex BRAM patterns
- Add "write_aiger -I -O -B"
* Formal Verification
- Added $changed support to read_verilog
- Added "read_verilog -noassert -noassume -assert-assumes"
- Added btor ops for $mul, $div, $mod and $concat
- Added yosys-smtbmc support for btor witnesses
- Added "supercover" pass
- Fixed $global_clock handling vs autowire
- Added $dffsr support to "async2sync"
- Added "fmcombine" pass
- Added memory init support in "write_btor"
- Added "cutpoint" pass
- Changed "ne" to "neq" in btor2 output
- Added support for SVA "final" keyword
- Added "fmcombine -initeq -anyeq"
- Added timescale and generated-by header to yosys-smtbmc vcd output
- Improved BTOR2 handling of undriven wires
* Verific support
- Enabled Verific flags vhdl_support_variable_slice and veri_elaborate_top_level_modules_having_interface_ports
- Improved support for asymmetric memories
- Added "verific -chparam"
- Fixed "verific -extnets" for more complex situations
- Added "read -verific" and "read -noverific"
- Added "hierarchy -chparam"
* New back-ends
- Added initial Anlogic support
- Added initial SmartFusion2 and IGLOO2 support
* ECP5 support
- Added "synth_ecp5 -nowidelut"
- Added BRAM inference support to "synth_ecp5"
- Added support for transforming Diamond IO and flipflop primitives
* iCE40 support
- Added "ice40_unlut" pass
- Added "synth_ice40 -relut"
- Added "synth_ice40 -noabc"
- Added "synth_ice40 -dffe_min_ce_use"
- Added DSP inference support using pmgen
- Added support for initialising BRAM primitives from a file
- Added iCE40 Ultra RGB LED driver cells
* Xilinx support
- Use "write_edif -pvector bra" for Xilinx EDIF files
- Fixes for VPR place and route support with "synth_xilinx"
- Added more cell simulation models
- Added "synth_xilinx -family"
- Added "stat -tech xilinx" to estimate logic cell usage
- Added "synth_xilinx -nocarry"
- Added "synth_xilinx -nowidelut"
- "synth_xilinx" to now infer hard shift registers (-nosrl to disable)
- Added support for mapping RAM32X1D
Yosys 0.7 .. Yosys 0.8
----------------------
* Various
- Many bugfixes and small improvements
- Strip debug symbols from installed binary
- Replace -ignore_redef with -[no]overwrite in front-ends
- Added write_verilog hex dump support, add -nohex option
- Added "write_verilog -decimal"
- Added "scc -set_attr"
- Added "verilog_defines" command
- Remember defines from one read_verilog to next
- Added support for hierarchical defparam
- Added FIRRTL back-end
- Improved ABC default scripts
- Added "design -reset-vlog"
- Added "yosys -W regex", "yosys -w regex", and "yosys -e regex"
- Added Verilog $rtoi and $itor support
- Added "check -initdrv"
- Added "read_blif -wideports"
- Added support for SystemVerilog "++" and "--" operators
- Added support for SystemVerilog unique, unique0, and priority case
- Added "write_edif" options for edif "flavors"
- Added support for resetall compiler directive
- Added simple C beck-end (bitwise combinatorical only atm)
- Added $_ANDNOT_ and $_ORNOT_ cell types
- Added cell library aliases to "abc -g"
- Added "setundef -anyseq"
- Added "chtype" command
- Added "design -import"
- Added "write_table" command
- Added "read_json" command
- Added "sim" command
- Added "extract_fa" and "extract_reduce" commands
- Added "extract_counter" command
- Added "opt_demorgan" command
- Added support for $size and $bits SystemVerilog functions
- Added "blackbox" command
- Added "ltp" command
- Added support for editline as replacement for readline
- Added warnings for driver-driver conflicts between FFs (and other cells) and constants
- Added "yosys -E" for creating Makefile dependencies files
- Added "synth -noshare"
- Added "memory_nordff"
- Added "setundef -undef -expose -anyconst"
- Added "expose -input"
- Added specify/specparam parser support (simply ignore them)
- Added "write_blif -inames -iattr"
- Added "hierarchy -simcheck"