From: Eddie Hung <eddie@fpgeh.com>
Date: Fri, 9 Aug 2019 16:50:47 +0000 (-0700)
Subject: A bit more on where $lcu comes from
X-Git-Tag: working-ls180~1154^2~1
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=acfb672d34092d67b0b3ed6a6ab45e5aac8e2bc0;p=yosys.git

A bit more on where $lcu comes from
---

diff --git a/techlibs/common/simlib.v b/techlibs/common/simlib.v
index f16866e86..1b172c112 100644
--- a/techlibs/common/simlib.v
+++ b/techlibs/common/simlib.v
@@ -537,6 +537,8 @@ endmodule
 //   used in binary arithmetic operations. By replacing the ripple
 //   carry structure used in full-adder blocks, the more significant
 //   bits of the sum can be expected to be computed more quickly.
+//   Typically created during `techmap` of $alu cells
+//   (see the "_90_alu" rule in +/techmap.v)
 module \$lcu (P, G, CI, CO);
 
 parameter WIDTH = 1;