synth - generic synthesis script

yosys> help synth

synth [options]

This command runs the default synthesis script. This command does not operate
on partly selected designs.

-top <module>

use the specified module as top module (default='top')

-auto-top

automatically determine the top of the design hierarchy

-flatten

flatten the design before synthesis. this will pass '-auto-top' to
'hierarchy' if no top module is specified.

-encfile <file>

passed to 'fsm_recode' via 'fsm'

-lut <k>

perform synthesis for a k-LUT architecture.

-nofsm

do not run FSM optimization

-noabc

do not run abc (as if yosys was compiled without ABC support)

-booth

run the booth pass to map $mul to Booth encoded multipliers

-noalumacc

do not run 'alumacc' pass. i.e. keep arithmetic operators in
their direct form ($add, $sub, etc.).

-nordff

passed to 'memory'. prohibits merging of FFs into memory read ports

-noshare

do not run SAT-based resource sharing

-run <from_label>[:<to_label>]

only run the commands between the labels (see below). an empty
from label is synonymous to 'begin', and empty to label is
synonymous to the end of the command list.

-abc9

use new ABC9 flow (EXPERIMENTAL)

-flowmap

use FlowMap LUT techmapping instead of ABC

-no-rw-check

marks all recognized read ports as "return don't-care value on
read/write collision" (same result as setting the no_rw_check
attribute on all memories).

-extra-map filename

source extra rules from the given file to complement the default
mapping library in the `techmap` step. this option can be
repeated.

The following commands are executed by this synthesis command:

    begin:
        hierarchy -check [-top <top> | -auto-top]

    coarse:
        proc
        flatten      (if -flatten)
        opt_expr
        opt_clean
        check
        opt -nodffe -nosdff
        fsm          (unless -nofsm)
        opt
        wreduce
        peepopt
        opt_clean
        techmap -map +/cmp2lut.v -map +/cmp2lcu.v     (if -lut)
        booth        (if -booth)
        alumacc      (unless -noalumacc)
        share        (unless -noshare)
        opt
        memory -nomap
        opt_clean

    fine:
        opt -fast -full
        memory_map
        opt -full
        techmap                      (unless -extra-map)
        techmap -map +/techmap.v -map <inject>      (if -extra-map)
        techmap -map +/gate2lut.v    (if -noabc and -lut)
        clean; opt_lut               (if -noabc and -lut)
        flowmap -maxlut K            (if -flowmap and -lut)
        opt -fast
        abc -fast           (unless -noabc, unless -lut)
        abc -fast -lut k    (unless -noabc, if -lut)
        opt -fast           (unless -noabc)

    check:
        hierarchy -check
        stat
        check