Merge pull request #805 from eddiehung/dff_init

write_verilog to write initial statement for initial flop state

backends/verilog/verilog_backend.cc

@@ -1310,6 +1310,15 @@ void dump_cell(std::ostream &f, std::string indent, RTLIL::Cell *cell)
 		}
 	}
 
+	if (reg_ct.count(cell->type) && cell->hasPort("\\Q")) {
+		std::stringstream ss;
+		dump_reg_init(ss, cell->getPort("\\Q"));
+		if (!ss.str().empty()) {
+			f << stringf("%sinitial %s.Q", indent.c_str(), cell_name.c_str());
+			f << ss.str();
+			f << ";\n";
+		}
+	}
 }
 
 void dump_conn(std::ostream &f, std::string indent, const RTLIL::SigSpec &left, const RTLIL::SigSpec &right)

tests/simple/dff_init.v

@@ -0,0 +1,42 @@
+module dff0_test(n1, n1_inv, clk);
+  input clk;
+  output n1;
+  reg n1 = 32'd0;
+  output n1_inv;
+  always @(posedge clk)
+      n1 <= n1_inv;
+  assign n1_inv = ~n1;
+endmodule
+
+module dff1_test(n1, n1_inv, clk);
+  input clk;
+  (* init = 32'd1 *)
+  output n1;
+  reg n1 = 32'd1;
+  output n1_inv;
+  always @(posedge clk)
+      n1 <= n1_inv;
+  assign n1_inv = ~n1;
+endmodule
+
+module dff0a_test(n1, n1_inv, clk);
+  input clk;
+  (* init = 32'd0 *) // Must be consistent with reg initialiser below
+  output n1;
+  reg n1 = 32'd0;
+  output n1_inv;
+  always @(posedge clk)
+      n1 <= n1_inv;
+  assign n1_inv = ~n1;
+endmodule
+
+module dff1a_test(n1, n1_inv, clk);
+  input clk;
+  (* init = 32'd1 *) // Must be consistent with reg initialiser below
+  output n1;
+  reg n1 = 32'd1;
+  output n1_inv;
+  always @(posedge clk)
+      n1 <= n1_inv;
+  assign n1_inv = ~n1;
+endmodule

tests/simple_defparam/run-test.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+OPTIND=1
+seed=""    # default to no seed specified
+while getopts "S:" opt
+do
+    case "$opt" in
+	S) arg="${OPTARG#"${OPTARG%%[![:space:]]*}"}" # remove leading space
+	   seed="SEED=$arg" ;;
+    esac
+done
+shift "$((OPTIND-1))"
+
+# check for Icarus Verilog
+if ! which iverilog > /dev/null ; then
+  echo "$0: Error: Icarus Verilog 'iverilog' not found."
+  exit 1
+fi
+
+cp ../simple/*.v .
+exec ${MAKE:-make} -f ../tools/autotest.mk $seed *.v EXTRA_FLAGS="-B \"-defparam\""

tests/tools/autotest.sh

@@ -28,7 +28,7 @@ if [ ! -f $toolsdir/cmp_tbdata -o $toolsdir/cmp_tbdata.c -nt $toolsdir/cmp_tbdat
 	( set -ex; ${CC:-gcc} -Wall -o $toolsdir/cmp_tbdata $toolsdir/cmp_tbdata.c; ) || exit 1
 fi
 
-while getopts xmGl:wkjvref:s:p:n:S:I:-: opt; do
+while getopts xmGl:wkjvref:s:p:n:S:I:B:-: opt; do
 	case "$opt" in
 		x)
 			use_xsim=true ;;
@@ -65,6 +65,8 @@ while getopts xmGl:wkjvref:s:p:n:S:I:-: opt; do
 			include_opts="$include_opts -I $OPTARG"
 			xinclude_opts="$xinclude_opts -i $OPTARG"
 			minclude_opts="$minclude_opts +incdir+$OPTARG" ;;
+        B)
+			backend_opts="$backend_opts $OPTARG" ;;
 		-)
 			case "${OPTARG}" in
 			    xfirrtl)
@@ -82,7 +84,7 @@ while getopts xmGl:wkjvref:s:p:n:S:I:-: opt; do
 				;;
 			esac;;
 		*)
-			echo "Usage: $0 [-x|-m] [-G] [-w] [-k] [-j] [-v] [-r] [-e] [-l libs] [-f frontend] [-s script] [-p cmdstring] [-n iters] [-S seed] [-I incdir] [--xfirrtl FIRRTL test exclude file] [--firrtl2verilog command to generate verilog from firrtl] verilog-files\n" >&2
+			echo "Usage: $0 [-x|-m] [-G] [-w] [-k] [-j] [-v] [-r] [-e] [-l libs] [-f frontend] [-s script] [-p cmdstring] [-n iters] [-S seed] [-I incdir] [-B backend_opt] [--xfirrtl FIRRTL test exclude file] [--firrtl2verilog command to generate verilog from firrtl] verilog-files\n" >&2
 			exit 1
 	esac
 done