8bitworkshop/test/cli/verilog/t_alw_nosplit.v

// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain, for
// any use, without warranty, 2018 by Wilson Snyder.
// SPDX-License-Identifier: CC0-1.0

module t (/*AUTOARG*/
   // Inputs
   clk
   );

   input clk;
   integer cyc; initial cyc=1;

   reg [15:0] m_din;

   // We expect none of these blocks to split.
   // Blocks that can split should go in t_alw_split.v instead.

   reg [15:0] b_split_1, b_split_2;
   always @ (/*AS*/m_din) begin
      b_split_1 = m_din;
      b_split_2 = b_split_1;
   end

   reg [15:0] c_split_1, c_split_2;
   always @ (/*AS*/m_din) begin
      c_split_1 = m_din;
      c_split_2 = c_split_1;
      c_split_1 = ~m_din;
   end

   always @ (posedge clk) begin
      $write(" foo %x", m_din);
      $write(" bar %x\n", m_din);
   end

   reg [15:0] e_split_1, e_split_2;
   always @ (posedge clk) begin
      e_split_1 = m_din;
      e_split_2 = e_split_1;
   end

   reg [15:0] f_split_1, f_split_2;
   always @ (posedge clk) begin
      f_split_2 = f_split_1;
      f_split_1 = m_din;
   end

   reg [15:0] l_split_1, l_split_2;
   always @ (posedge clk) begin
      l_split_2 <= l_split_1;
      l_split_1 <= l_split_2 | m_din;
   end

   reg [15:0] z_split_1, z_split_2;
   always @ (posedge clk) begin
      z_split_1 <= 0;
      z_split_1 <= ~m_din;
   end
   always @ (posedge clk) begin
      z_split_2 <= 0;
      z_split_2 <= z_split_1;
   end

   reg [15:0] h_split_1;
   reg [15:0] h_split_2;
   reg [15:0] h_foo;
   always @ (posedge clk) begin
//      $write(" cyc = %x  m_din = %x\n", cyc, m_din);
      h_foo = m_din;
      if (cyc > 2) begin
         // This conditional depends on non-primary-input foo.
         // Its dependency on foo should not be pruned. As a result,
         // the dependencies of h_split_1 and h_split_2 on this
         // conditional will also not be pruned, making them all
         // weakly connected such that they'll end up in the same graph
         // and we can't split.
         if (h_foo == 16'h0) begin
            h_split_1 <= 16'h0;
            h_split_2 <= 16'h0;
         end
         else begin
            h_split_1 <= m_din;
            h_split_2 <= ~m_din;
         end
      end
      else begin
         h_split_1 <= 16'h0;
         h_split_2 <= 16'h0;
      end
   end  // always @ (posedge clk)

   always @ (posedge clk) begin
      if (cyc!=0) begin
         cyc<=cyc+1;
      end
      if (cyc==1) begin
         m_din <= 16'hfeed;
      end
      if (cyc==4) begin
         m_din <= 16'he11e;
         if (!(b_split_1==16'hfeed && b_split_2==16'hfeed)) $stop;
         if (!(c_split_1==16'h0112 && c_split_2==16'hfeed)) $stop;
         if (!(e_split_1==16'hfeed && e_split_2==16'hfeed)) $stop;
         if (!(f_split_1==16'hfeed && f_split_2==16'hfeed)) $stop;
         if (!(z_split_1==16'h0112 && z_split_2==16'h0112)) $stop;
      end
      if (cyc==5) begin
         m_din <= 16'he22e;
         if (!(b_split_1==16'he11e && b_split_2==16'he11e)) $stop;
         if (!(c_split_1==16'h1ee1 && c_split_2==16'he11e)) $stop;
         // Two valid orderings, as we don't know which posedge clk gets evaled first
         if (!(e_split_1==16'hfeed && e_split_2==16'hfeed) && !(e_split_1==16'he11e && e_split_2==16'he11e)) $stop;
         if (!(f_split_1==16'hfeed && f_split_2==16'hfeed) && !(f_split_1==16'he11e && f_split_2==16'hfeed)) $stop;
         if (!(z_split_1==16'h0112 && z_split_2==16'h0112)) $stop;
      end
      if (cyc==6) begin
         m_din <= 16'he33e;
         if (!(b_split_1==16'he22e && b_split_2==16'he22e)) $stop;
         if (!(c_split_1==16'h1dd1 && c_split_2==16'he22e)) $stop;
         // Two valid orderings, as we don't know which posedge clk gets evaled first
         if (!(e_split_1==16'he11e && e_split_2==16'he11e) && !(e_split_1==16'he22e && e_split_2==16'he22e)) $stop;
         if (!(f_split_1==16'he11e && f_split_2==16'hfeed) && !(f_split_1==16'he22e && f_split_2==16'he11e)) $stop;
         if (!(z_split_1==16'h1ee1 && z_split_2==16'h0112)) $stop;
      end
      if (cyc==7) begin
         $write("*-* All Finished *-*\n");
         $finish;
      end
   end
endmodule