JT51 + CXXRTL = <3

jt51_driver.cc

// Step 1: Obtain latest Yosys from https://github.com/YosysHQ/yosys/.
// Step 2: Download jt51 from https://github.com/jotego/jt51.
// Step 3: Build as follows:
//   $ yosys jt51/hdl/*.v -b 'cxxrtl -header' -o jt51_core.cc
//   $ CFLAGS="-fbracket-depth=2048 -I$(yosys-config --datdir/include)"
//   $ clang++ -O3 $CFLAGS jt51_core.cc jt51_driver.cc -o jt51_sim
// Step 4: Enjoy!

#include <fstream>
#include <backends/cxxrtl/cxxrtl_vcd.h>
#include "jt51_core.h"

int main() {
  cxxrtl_design::p_jt51 top;

  cxxrtl::debug_items debug;
  top.debug_info(debug);

  size_t steps = 1;
  std::ofstream waves("jt51.vcd");
  cxxrtl::vcd_writer vcd;
  vcd.timescale(1, "us");

  auto traces = {
    "rst", "clk", "cen", "cen_p1", "cs_n", "wr_n", "a0", "din", "busy",
    "xleft", "xright",
  };
  for (auto name : traces)
    vcd.add(name, debug.at(name));

  top.p_rst    .set(1u);
  top.p_clk    .set(0u);
  top.p_cen    .set(1u);
  top.p_cen__p1.set(1u);
  top.p_din    .set(0u);
  top.p_a0     .set(0u);
  top.p_cs__n  .set(0u);
  top.p_wr__n  .set(1u);
  top.step();
  vcd.sample(steps++);

  size_t index = 0;
  std::vector<std::pair<uint8_t, uint8_t>> prog = {
    {0x20,0xC7},
    {0x28,0x4A},
    {0x40,0x01},
    {0x60,0x00},
    {0x80,0x1F},
    {0xA0,0x00},
    {0xE0,0xFF},
    {0x08,0x08},
    {0x28,0x4A},
  };

  while (steps < 100000) {
    if (steps < 1000) {
      top.p_rst.set(1u);
    } else {
      top.p_rst.set(0u);
      if (index < prog.size()) {
        switch (steps % 200) {
          case 0:
            top.p_a0   .set(0u);
            top.p_din  .set(prog[index].first);
            top.p_wr__n.set(0u);
            break;
          case 10:
            top.p_wr__n.set(1u);
            break;
          case 20:
            top.p_a0   .set(1u);
            top.p_din  .set(prog[index].second);
            top.p_wr__n.set(0u);
            break;
          case 30:
            top.p_wr__n.set(1u);
            index++;
            break;
        }
      }
    }

    top.p_cen__p1.set<bool>(!top.p_cen__p1.get<bool>());
    top.p_clk.set(0u);
    top.step();
    vcd.sample(steps++);

    top.p_clk.set(1u);
    top.step();
    vcd.sample(steps++);

    waves << vcd.buffer;
    vcd.buffer.clear();
  }

  return 0;
}

waaaaaaves