yosys是linux系统,yosys

yosys -- Yosys Open SYnthesis Suite

Copyright (C) 2012 - 2020 Claire Wolf

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yosys – Yosys Open SYnthesis Suite

This is a framework for RTL synthesis tools. It currently has

extensive Verilog-2005 support and provides a basic set of

synthesis algorithms for various application domains.

Yosys can be adapted to perform any synthesis job by combining

the existing passes (algorithms) using synthesis scripts and

adding additional passes as needed by extending the yosys C++

code base.

Yosys is free software licensed under the ISC license (a GPL

compatible license that is similar in terms to the MIT license

or the 2-clause BSD license).

Web Site and Other Resources

More information and documentation can be found on the Yosys web site:

The "Documentation" page on the web site contains links to more resources,

including a manual that even describes some of the Yosys internals:

The file CodingReadme in this directory contains additional information

for people interested in using the Yosys C++ APIs.

Users interested in formal verification might want to use the formal verification

front-end for Yosys, SymbiYosys:

Setup

You need a C++ compiler with C++11 support (up-to-date CLANG or GCC is

recommended) and some standard tools such as GNU Flex, GNU Bison, and GNU Make.

TCL, readline and libffi are optional (see ENABLE_* settings in Makefile).

Xdot (graphviz) is used by the show command in yosys to display schematics.

For example on Ubuntu Linux 16.04 LTS the following commands will install all

prerequisites for building yosys:

$ sudo apt-get install build-essential clang bison flex \

libreadline-dev gawk tcl-dev libffi-dev git \

graphviz xdot pkg-config python3 libboost-system-dev \

libboost-python-dev libboost-filesystem-dev zlib1g-dev

Similarily, on Mac OS X Homebrew can be used to install dependencies (from within cloned yosys repository):

$ brew tap Homebrew/bundle && brew bundle

or MacPorts:

$ sudo port install bison flex readline gawk libffi \

git graphviz pkgconfig python36 boost zlib tcl

On FreeBSD use the following command to install all prerequisites:

# pkg install bison flex readline gawk libffi\

git graphviz pkgconf python3 python36 tcl-wrapper boost-libs

On FreeBSD system use gmake instead of make. To run tests use:

% MAKE=gmake CC=cc gmake test

For Cygwin use the following command to install all prerequisites, or select these additional packages:

setup-x86_64.exe -q --packages=bison,flex,gcc-core,gcc-g++,git,libffi-devel,libreadline-devel,make,pkg-config,python3,tcl-devel,boost-build,zlib-devel

There are also pre-compiled Yosys binary packages for Ubuntu and Win32 as well

as a source distribution for Visual Studio. Visit the Yosys download page for

more information: http://www.clifford.at/yosys/download.html

To configure the build system to use a specific compiler, use one of

$ make config-clang

$ make config-gcc

For other compilers and build configurations it might be

necessary to make some changes to the config section of the

Makefile.

$ vi Makefile # ..or..

$ vi Makefile.conf

To build Yosys simply type 'make' in this directory.

$ make

$ sudo make install

Note that this also downloads, builds and installs ABC (using yosys-abc

as executable name).

Tests are located in the tests subdirectory and can be executed using the test target. Note that you need gawk as well as a recent version of iverilog (i.e. build from git). Then, execute tests via:

$ make test

To use a separate (out-of-tree) build directory, provide a path to the Makefile.

$ mkdir build; cd build

$ make -f ../Makefile

Out-of-tree builds require a clean source tree.

Getting Started

Yosys can be used with the interactive command shell, with

synthesis scripts or with command line arguments. Let's perform

a simple synthesis job using the interactive command shell:

$ ./yosys

yosys>

the command help can be used to print a list of all available

commands and help to print details on the specified command:

yosys> help help

reading and elaborating the design using the Verilog frontend:

yosys> read -sv tests/simple/fiedler-cooley.v

yosys> hierarchy -top up3down5

writing the design to the console in Yosys's internal format:

yosys> write_ilang

convert processes (always blocks) to netlist elements and perform

some simple optimizations:

yosys> proc; opt

display design netlist using xdot:

yosys> show

the same thing using gv as postscript viewer:

yosys> show -format ps -viewer gv

translating netlist to gate logic and perform some simple optimizations:

yosys> techmap; opt

write design netlist to a new Verilog file:

yosys> write_verilog synth.v

or using a simple synthesis script:

$ cat synth.ys

read -sv tests/simple/fiedler-cooley.v

hierarchy -top up3down5

proc; opt; techmap; opt

write_verilog synth.v

$ ./yosys synth.ys

If ABC is enabled in the Yosys build configuration and a cell library is given

in the liberty file mycells.lib, the following synthesis script will

synthesize for the given cell library:

# read design

read -sv tests/simple/fiedler-cooley.v

hierarchy -top up3down5

# the high-level stuff

proc; fsm; opt; memory; opt

# mapping to internal cell library

techmap; opt

# mapping flip-flops to mycells.lib

dfflibmap -liberty mycells.lib

# mapping logic to mycells.lib

abc -liberty mycells.lib

# cleanup

clean

If you do not have a liberty file but want to test this synthesis script,

you can use the file examples/cmos/cmos_cells.lib from the yosys sources

as simple example.

Liberty file downloads for and information about free and open ASIC standard

cell libraries can be found here:

The command synth provides a good default synthesis script (see

help synth):

read -sv tests/simple/fiedler-cooley.v

synth -top up3down5

# mapping to target cells

dfflibmap -liberty mycells.lib

abc -liberty mycells.lib

clean

The command prep provides a good default word-level synthesis script, as

used in SMT-based formal verification.

Unsupported Verilog-2005 Features

The following Verilog-2005 features are not supported by

Yosys and there are currently no plans to add support

for them:

Non-synthesizable language features as defined in

IEC 62142(E):2005 / IEEE Std. 1364.1(E):2002

The tri, triand and trior net types

The config and disable keywords and library map files

Verilog Attributes and non-standard features

The full_case attribute on case statements is supported

(also the non-standard // synopsys full_case directive)

The parallel_case attribute on case statements is supported

(also the non-standard // synopsys parallel_case directive)

The // synopsys translate_off and // synopsys translate_on

directives are also supported (but the use of `ifdef .. `endif

is strongly recommended instead).

The nomem2reg attribute on modules or arrays prohibits the

automatic early conversion of arrays to separate registers. This

is potentially dangerous. Usually the front-end has good reasons

for converting an array to a list of registers. Prohibiting this

step will likely result in incorrect synthesis results.

The mem2reg attribute on modules or arrays forces the early

conversion of arrays to separate registers.

The nomeminit attribute on modules or arrays prohibits the

creation of initialized memories. This effectively puts mem2reg

on all memories that are written to in an initial block and

are not ROMs.

The nolatches attribute on modules or always-blocks

prohibits the generation of logic-loops for latches. Instead

all not explicitly assigned values default to x-bits. This does

not affect clocked storage elements such as flip-flops.

The nosync attribute on registers prohibits the generation of a

storage element. The register itself will always have all bits set

to 'x' (undefined). The variable may only be used as blocking assigned

temporary variable within an always block. This is mostly used internally

by Yosys to synthesize Verilog functions and access arrays.

The nowrshmsk attribute on a register prohibits the generation of

shift-and-mask type circuits for writing to bit slices of that register.

The onehot attribute on wires mark them as one-hot state register. This

is used for example for memory port sharing and set by the fsm_map pass.

The blackbox attribute on modules is used to mark empty stub modules

that have the same ports as the real thing but do not contain information

on the internal configuration. This modules are only used by the synthesis

passes to identify input and output ports of cells. The Verilog backend

also does not output blackbox modules on default. read_verilog, unless

called with -noblackbox will automatically set the blackbox attribute

on any empty module it reads.

The noblackbox attribute set on an empty module prevents read_verilog

from automatically setting the blackbox attribute on the module.

The whitebox attribute on modules triggers the same behavior as

blackbox, but is for whitebox modules, i.e. library modules that

contain a behavioral model of the cell type.

The lib_whitebox attribute overwrites whitebox when read_verilog

is run in -lib mode. Otherwise it's automatically removed.

The dynports attribute is used by the Verilog front-end to mark modules

that have ports with a width that depends on a parameter.

The hdlname attribute is used by some passes to document the original

(HDL) name of a module when renaming a module.

The keep attribute on cells and wires is used to mark objects that should

never be removed by the optimizer. This is used for example for cells that

have hidden connections that are not part of the netlist, such as IO pads.

Setting the keep attribute on a module has the same effect as setting it

on all instances of the module.

The keep_hierarchy attribute on cells and modules keeps the flatten

command from flattening the indicated cells and modules.

The init attribute on wires is set by the frontend when a register is

initialized "FPGA-style" with reg foo = val. It can be used during

synthesis to add the necessary reset logic.

The top attribute on a module marks this module as the top of the

design hierarchy. The hierarchy command sets this attribute when called

with -top. Other commands, such as flatten and various backends

use this attribute to determine the top module.

The src attribute is set on cells and wires created by to the string

: by the HDL front-end and is then carried

through the synthesis. When entities are combined, a new |-separated

string is created that contains all the string from the original entities.

The defaultvalue attribute is used to store default values for

module inputs. The attribute is attached to the input wire by the HDL

front-end when the input is declared with a default value.

The parameter and localparam attributes are used to mark wires

that represent module parameters or localparams (when the HDL front-end

is run in -pwires mode).

Wires marked with the hierconn attribute are connected to wires with the

same name (format cell_name.identifier) when they are imported from

sub-modules by flatten.

The clkbuf_driver attribute can be set on an output port of a blackbox

module to mark it as a clock buffer output, and thus prevent clkbufmap

from inserting another clock buffer on a net driven by such output.

The clkbuf_sink attribute can be set on an input port of a module to

request clock buffer insertion by the clkbufmap pass.

The clkbuf_inv attribute can be set on an output port of a module

with the value set to the name of an input port of that module. When

the clkbufmap would otherwise insert a clock buffer on this output,

it will instead try inserting the clock buffer on the input port (this

is used to implement clock inverter cells that clock buffer insertion

will "see through").

The clkbuf_inhibit is the default attribute to set on a wire to prevent

automatic clock buffer insertion by clkbufmap. This behaviour can be

overridden by providing a custom selection to clkbufmap.

The invertible_pin attribute can be set on a port to mark it as

invertible via a cell parameter. The name of the inversion parameter

is specified as the value of this attribute. The value of the inversion

parameter must be of the same width as the port, with 1 indicating

an inverted bit and 0 indicating a non-inverted bit.

The iopad_external_pin attribute on a blackbox module's port marks

it as the external-facing pin of an I/O pad, and prevents iopadmap

from inserting another pad cell on it.

The module attribute abc9_lut is an integer attribute indicating to

abc9 that this module describes a LUT with an area cost of this value, and

propagation delays described using specify statements.

The module attribute abc9_box is a boolean specifying a black/white-box

definition, with propagation delays described using specify statements, for

use by abc9.

The port attribute abc9_carry marks the carry-in (if an input port) and

carry-out (if output port) ports of a box. This information is necessary for

abc9 to preserve the integrity of carry-chains. Specifying this attribute

onto a bus port will affect only its most significant bit.

The module attribute abc9_flop is a boolean marking the module as a

flip-flop. This allows abc9 to analyse its contents in order to perform

sequential synthesis.

The frontend sets attributes always_comb, always_latch and

always_ff on processes derived from SystemVerilog style always blocks

according to the type of the always. These are checked for correctness in

proc_dlatch.

The cell attribute wildcard_port_conns represents wildcard port

connections (SystemVerilog .*). These are resolved to concrete

connections to matching wires in hierarchy.

In addition to the (* ... *) attribute syntax, Yosys supports

the non-standard {* ... *} attribute syntax to set default attributes

for everything that comes after the {* ... *} statement. (Reset

by adding an empty {* *} statement.)

In module parameter and port declarations, and cell port and parameter

lists, a trailing comma is ignored. This simplifies writing Verilog code

generators a bit in some cases.

Modules can be declared with module mod_name(...); (with three dots

instead of a list of module ports). With this syntax it is sufficient

to simply declare a module port as 'input' or 'output' in the module

body.

When defining a macro with `define, all text between triple double quotes

is interpreted as macro body, even if it contains unescaped newlines. The

triple double quotes are removed from the macro body. For example:

`define MY_MACRO(a, b) """

assign a = 23;

assign b = 42;

"""

The attribute via_celltype can be used to implement a Verilog task or

function by instantiating the specified cell type. The value is the name

of the cell type to use. For functions the name of the output port can

be specified by appending it to the cell type separated by a whitespace.

The body of the task or function is unused in this case and can be used

to specify a behavioral model of the cell type for simulation. For example:

module my_add3(A, B, C, Y);

parameter WIDTH = 8;

input [WIDTH-1:0] A, B, C;

output [WIDTH-1:0] Y;

...

endmodule

module top;

...

(* via_celltype = "my_add3 Y" *)

(* via_celltype_defparam_WIDTH = 32 *)

function [31:0] add3;

input [31:0] A, B, C;

begin

add3 = A + B + C;

end

endfunction

...

endmodule

The wiretype attribute is added by the verilog parser for wires of a

typedef'd type to indicate the type identifier.

Various enum_value_{value} attributes are added to wires of an enumerated type

to give a map of possible enum items to their values.

The enum_base_type attribute is added to enum items to indicate which

enum they belong to (enums -- anonymous and otherwise -- are

automatically named with an auto-incrementing counter). Note that enums

are currently not strongly typed.

A limited subset of DPI-C functions is supported. The plugin mechanism

(see help plugin) can be used to load .so files with implementations

of DPI-C routines. As a non-standard extension it is possible to specify

a plugin alias using the : syntax. For example:

module dpitest;

import "DPI-C" function foo:round = real my_round (real);

parameter real r = my_round(12.345);

endmodule

$ yosys -p 'plugin -a foo -i /lib/libm.so; read_verilog dpitest.v'

Sized constants (the syntax 's?[bodh]) support constant

expressions as . If the expression is not a simple identifier, it

must be put in parentheses. Examples: WIDTH'd42, (4+2)'b101010

The system tasks $finish, $stop and $display are supported in

initial blocks in an unconditional context (only if/case statements on

expressions over parameters and constant values are allowed). The intended

use for this is synthesis-time DRC.

There is limited support for converting specify .. endspecify

statements to special $specify2, $specify3, and $specrule cells,

for use in blackboxes and whiteboxes. Use read_verilog -specify to

enable this functionality. (By default these blocks are ignored.)

Non-standard or SystemVerilog features for formal verification

Support for assert, assume, restrict, and cover is enabled

when read_verilog is called with -formal.

The system task $initstate evaluates to 1 in the initial state and

to 0 otherwise.

The system function $anyconst evaluates to any constant value. This is

equivalent to declaring a reg as rand const, but also works outside

of checkers. (Yosys also supports rand const outside checkers.)

The system function $anyseq evaluates to any value, possibly a different

value in each cycle. This is equivalent to declaring a reg as rand,

but also works outside of checkers. (Yosys also supports rand

variables outside checkers.)

The system functions $allconst and $allseq can be used to construct

formal exist-forall problems. Assumptions only hold if the trace satisfies

the assumption for all $allconst/$allseq values. For assertions and cover

statements it is sufficient if just one $allconst/$allseq value triggers

the property (similar to $anyconst/$anyseq).

Wires/registers declared using the anyconst/anyseq/allconst/allseq attribute

(for example (* anyconst *) reg [7:0] foobar;) will behave as if driven

by a $anyconst/$anyseq/$allconst/$allseq function.

The SystemVerilog tasks $past, $stable, $rose and $fell are

supported in any clocked block.

The syntax @($global_clock) can be used to create FFs that have no

explicit clock input ($ff cells). The same can be achieved by using

@(posedge ) or @(negedge ) when

is marked with the (* gclk *) Verilog attribute.

Supported features from SystemVerilog

When read_verilog is called with -sv, it accepts some language features

from SystemVerilog:

The assert statement from SystemVerilog is supported in its most basic

form. In module context: assert property (); and within an

always block: assert();. It is transformed to an $assert cell.

The assume, restrict, and cover statements from SystemVerilog are

also supported. The same limitations as with the assert statement apply.

The keywords always_comb, always_ff and always_latch, logic

and bit are supported.

Declaring free variables with rand and rand const is supported.

Checkers without a port list that do not need to be instantiated (but instead

behave like a named block) are supported.

SystemVerilog packages are supported. Once a SystemVerilog file is read

into a design with read_verilog, all its packages are available to

SystemVerilog files being read into the same design afterwards.

typedefs are supported (including inside packages)

type casts are currently not supported

enums are supported (including inside packages)

but are currently not strongly typed

SystemVerilog interfaces (SVIs) are supported. Modports for specifying whether

ports are inputs or outputs are supported.

Building the documentation

Note that there is no need to build the manual if you just want to read it.

Simply download the PDF from http://www.clifford.at/yosys/documentation.html

instead.

On Ubuntu, texlive needs these packages to be able to build the manual:

sudo apt-get install texlive-binaries

sudo apt-get install texlive-science # install algorithm2e.sty

sudo apt-get install texlive-bibtex-extra # gets multibib.sty

sudo apt-get install texlive-fonts-extra # gets skull.sty and dsfont.sty

sudo apt-get install texlive-publishers # IEEEtran.cls

Also the non-free font luximono should be installed, there is unfortunately

no Ubuntu package for this so it should be installed separately using

getnonfreefonts:

wget https://tug.org/fonts/getnonfreefonts/install-getnonfreefonts

sudo texlua install-getnonfreefonts # will install to /usr/local by default, can be changed by editing BINDIR at MANDIR at the top of the script

getnonfreefonts luximono # installs to /home/user/texmf

Then execute, from the root of the repository:

make manual

Notes:

To run make manual you need to have installed Yosys with make install,

otherwise it will fail on finding kernel/yosys.h while building

PRESENTATION_Prog.