From: Sebastien Bourdeauducq <sebastien@milkymist.org>
Date: Sat, 17 Dec 2011 14:20:22 +0000 (+0100)
Subject: verilog: get the simulator to run the combinatorial process at the beginning
X-Git-Tag: 24jan2021_ls180~2099^2~1130
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=6f8a6db40a64df0272daf25979d8dbe6fa984ce8;p=litex.git

verilog: get the simulator to run the combinatorial process at the beginning
---

diff --git a/migen/fhdl/verilog.py b/migen/fhdl/verilog.py
index ac9892f3..24670228 100644
--- a/migen/fhdl/verilog.py
+++ b/migen/fhdl/verilog.py
@@ -155,8 +155,23 @@ def Convert(f, ios=set(), name="top", clk_signal=None, rst_signal=None, ns=None)
 	r += "\n"
 	
 	if f.comb.l:
+		# Generate a dummy event to get the simulator
+		# to run the combinatorial process once at the beginning.
+		syn_off = "// synthesis translate off\n"
+		syn_on = "// synthesis translate on\n"
+		dummy_s = Signal(name="dummy_s")
+		dummy_d = Signal(name="dummy_d")
+		r += syn_off
+		r += "reg " + _printsig(ns, dummy_s) + ";\n"
+		r += "reg " + _printsig(ns, dummy_d) + ";\n"
+		r += "initial " + ns.get_name(dummy_s) + " <= 1'b0;\n"
+		r += syn_on + "\n"
+		
 		r += "always @(*) begin\n"
 		r += _printnode(ns, 1, f.comb)
+		r += syn_off
+		r += "\t" + ns.get_name(dummy_d) + " <= " + ns.get_name(dummy_s) + ";\n"
+		r += syn_on
 		r += "end\n\n"
 	if f.sync.l:
 		r += "always @(posedge " + ns.get_name(clk_signal) + ") begin\n"