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Wilson Snyder 2019-02-26 18:24:46 -05:00
parent 8a43f41ed6
commit d1548b1161
1 changed files with 9 additions and 9 deletions
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@ -1455,10 +1455,10 @@ Enable all code style related warning messages. This is equivalent to
=item --x-assign unique
Controls the two-state value that is replaced when an assignment to X is
encountered. --x-assign=fast, the default, converts all Xs to whatever is
best for performance. --x-assign=0 converts all Xs to 0s, and is also fast.
--x-assign=1 converts all Xs to 1s, this is nearly as fast as 0, but more
likely to find reset bugs as active high logic will fire. --x-assign=unique
encountered. C<--x-assign fast>, the default, converts all Xs to whatever is
best for performance. C<--x-assign 0> converts all Xs to 0s, and is also fast.
C<--x-assign 1> converts all Xs to 1s, this is nearly as fast as 0, but more
likely to find reset bugs as active high logic will fire. C<--x-assign unique>
will call a function to determine the value, this allows randomization of
all Xs to find reset bugs and is the slowest, but safest for finding reset
bugs in code.
@ -1483,13 +1483,13 @@ variables are controlled with --x-initial.
Controls the two-state value that is used to initialize variables that are
not otherwise initialized.
--x-initial=0, initializes all otherwise uninitialized variables to zero.
C<--x-initial 0>, initializes all otherwise uninitialized variables to zero.
--x-initial=unique, the default, initializes variables using a function,
C<--x-initial unique>, the default, initializes variables using a function,
which determines the value to use each initialization. This gives greatest
flexibility and allows finding reset bugs. See L</"Unknown states">.
--x-initial=fast, is best for performance, and initializes all variables to
C<--x-initial fast>, is best for performance, and initializes all variables to
a state Verilator determines is optimal. This may allow further code
optimizations, but will likely hide any code bugs relating to missing
resets.
@ -1764,8 +1764,8 @@ the examples directory in the distribution.
=head1 BENCHMARKING & OPTIMIZATION
For best performance, run Verilator with the "-O3 --x-assign=fast
--x-initial=fast --noassert" flags. The -O3 flag will require longer
compile times, and --x-assign=fast --x-initial=fast may increase the risk
--x-initial fast --noassert" flags. The -O3 flag will require longer
compile times, and "--x-assign fast --x-initial fast" may increase the risk
of reset bugs in trade for performance; see the above documentation for
these flags.