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-rw-r--r--backends/verilog/verilog_backend.cc9
-rw-r--r--tests/simple/dff_init.v42
2 files changed, 51 insertions, 0 deletions
diff --git a/backends/verilog/verilog_backend.cc b/backends/verilog/verilog_backend.cc
index 60668f1f0..d351a6266 100644
--- a/backends/verilog/verilog_backend.cc
+++ b/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)
diff --git a/tests/simple/dff_init.v b/tests/simple/dff_init.v
new file mode 100644
index 000000000..be947042e
--- /dev/null
+++ b/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