From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Thu, 2 Jul 2020 21:30:43 +0000 (+0100)
Subject: use Mux in latchregister, try to break "loops"
X-Git-Tag: 24jan2021_ls180~46
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=0bc469afb6c9a7739de1cb7f2add2881c44bf3ff;p=nmutil.git

use Mux in latchregister, try to break "loops"
---

diff --git a/src/nmutil/latch.py b/src/nmutil/latch.py
index 1c22483..813ad64 100644
--- a/src/nmutil/latch.py
+++ b/src/nmutil/latch.py
@@ -1,6 +1,6 @@
 from nmigen.compat.sim import run_simulation
 from nmigen.cli import verilog, rtlil
-from nmigen import Record, Signal, Module, Const, Elaboratable
+from nmigen import Record, Signal, Module, Const, Elaboratable, Mux
 
 """ jk latch
 
@@ -21,6 +21,7 @@ always @ (posedge c)
 endmodule
 """
 
+
 def latchregister(m, incoming, outgoing, settrue, name=None):
     """latchregister
 
@@ -36,17 +37,17 @@ def latchregister(m, incoming, outgoing, settrue, name=None):
         reg = Record.like(incoming, name=name)
     else:
         reg = Signal.like(incoming, name=name)
+    m.d.comb += outgoing.eq(Mux(settrue, incoming, reg))
     with m.If(settrue): # pass in some kind of expression/condition here
         m.d.sync += reg.eq(incoming)      # latch input into register
-        m.d.comb += outgoing.eq(incoming) # return input (combinatorial)
-    with m.Else():
-        m.d.comb += outgoing.eq(reg) # return input (combinatorial)
+
 
 def mkname(prefix, suffix):
     if suffix is None:
         return prefix
     return "%s_%s" % (prefix, suffix)
 
+
 class SRLatch(Elaboratable):
     def __init__(self, sync=True, llen=1, name=None):
         self.sync = sync