Add a separate shiftmul pattern to match on left shifts which implement
demuxing. This mirrors the right shift pattern matcher but is probably
best kept separate instead of merging the two into a single matcher.
In any case the diff of the two matchers should be easily readable.
The `opt_expr` pass running before `peepopt` can interfere with the
detection of a shiftmul pattern due to some of the bottom bits of the
shift amount being replaced with constant zero. Extend the detection to
cover those situations as well.
Combined presentation sections with appnote sections.
Moved a bunch of Yosys one-liners in-line.
Better reference in interactive investigation to memdemo as a part of advanced logic cone selection (esp. because the show commands use some of the advanced features)
More :numref: because I figured out they were only failing if I didn't do a full re-make.
Reflow first section a little to help readability.
Also includes a css change to prevent code block caption text from bunching into the caption number.
Mostly in the `more_scripting` section, with part of the intro in the `scripting_intro`.
Also includes an extra todo on the installation page and some extra notes on where to find `show` details where relevant.
Images now included relative to the `docs/source` folder instead of the rst file.
Also makes sure to add the updated `yosyshq.css` (which as a sidenote has ended up as `custom.css` in most of the other docs).
The Verilog grammar does not allow an empty case. Most synthesis tools
are quite permissive about this, but Quartus is not. This causes
problems for amaranth with Quartus (see amaranth-lang/amaranth#931).
`memory_nordff` has the advantage that it can be called just ahead of
the simulation step no matter whether the clocked read port has been
inferred or was explicitly instantiated in a flow.
