This reverts commit 08be796cb8, reversing
changes made to 38dbb44fa0.
This fixes#2728. PR #641 did not actually "fix" #639.
The actual issue in #639 is not equiv_make, but assumptions in equiv_simple
that are not true for the test case provided in #639.
This is a complete rewrite of the FF replacing code.
The previous implementation tried to implement the negative hold time by
wrapping async control signals individually with pulse stretching. This
did not correctly model the interaction between different simultaneously
changing inputs (e.g. a falling ALOAD together with a changing AD would
load the changed AD instead of the value AD had when ALOAD was high; a
falling CLR could mask a raising SET for one cycle; etc.).
The new approach first has the logic for all updates using only sampled
values followed by the logic for all updates using only current values.
That way, e.g., a falling ALOAD will load the sampled AD value but a
still active ALOAD will load the current AD value.
The new code also has deterministic behavior for the initial state: no
operation is active when that operation would depend on a specific
previous signal value. This also means clk2fflogic will no longer
generate any additional uninitialized FFs.
I also documented the negative hold time behavior in the help message,
copying the relevant part from async2sync's help messages.
On Posix systems, the path /bin/bash is not guaranteed to
exist and it is more portable to use /usr/bin/env instead.
Fixing this for yosys-config with is the most important for
a functioning installation.
Signed-off-by: Henner Zeller <h.zeller@acm.org>
In 2fcc1ee72e, the following is apparantly added in order to mark any
number of undefined LUT inputs:
lut_a.append(RTLIL::Const(State::Sx, minlut - input_nodes.size()));
However this can only be done if the number of input nodes is less
than minlut.
This fixes#3317
This PR replaces the old markdown issue template with the new YAML based form templates for GitHub, this allows us to enforce required fields and also auto-tag with labels.
This doesn't remove the ability to open a blank issue, but it is obscured so it is not the primary thing people are likely to do.
This also added link entries in the issue creation page to link to the Discussions tab, Community Slack, and IRC channel.
