diff --git a/verisim/Makefile b/verisim/Makefile
index 73a92e90..d4ca59a1 100644
--- a/verisim/Makefile
+++ b/verisim/Makefile
@@ -31,7 +31,7 @@ sim_vsrcs = \
 	$(testchip_vsrcs)
 
 sim_csrcs = \
-	$(testchip_dir)/csrc/verilator-harness.cc \
+	$(sim_dir)/csrc/verilator-harness.cc \
 	$(testchip_csrcs)
 
 model_dir = $(build_dir)/$(long_name)
diff --git a/verisim/csrc/verilator-harness.cc b/verisim/csrc/verilator-harness.cc
new file mode 100644
index 00000000..475123c3
--- /dev/null
+++ b/verisim/csrc/verilator-harness.cc
@@ -0,0 +1,167 @@
+// See LICENSE for license details.
+
+#include "verilated.h"
+#if VM_TRACE
+#include "verilated_vcd_c.h"
+#endif
+#include <fesvr/tsi.h>
+#include <iostream>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+extern tsi_t* tsi;
+static uint64_t trace_count = 0;
+bool verbose;
+bool done_reset;
+
+void handle_sigterm(int sig)
+{
+  tsi->stop();
+}
+
+double sc_time_stamp()
+{
+  return trace_count;
+}
+
+extern "C" int vpi_get_vlog_info(void* arg)
+{
+  return 0;
+}
+
+static inline int copy_argv(int argc, char **argv, char **new_argv)
+{
+    int optind = 1;
+    int new_argc = argc;
+
+    new_argv[0] = argv[0];
+
+    for (int i = 1; i < argc; i++) {
+        if (argv[i][0] != '+' && argv[i][0] != '-') {
+            optind = i - 1;
+            new_argc = argc - i + 1;
+            break;
+        }
+    }
+
+    for (int i = 1; i < new_argc; i++)
+        new_argv[i] = argv[i + optind];
+
+    return new_argc;
+}
+
+int main(int argc, char** argv)
+{
+  unsigned random_seed = (unsigned)time(NULL) ^ (unsigned)getpid();
+  uint64_t max_cycles = -1;
+  uint64_t start = 0;
+  int ret = 0;
+  FILE *vcdfile = NULL;
+  bool print_cycles = false;
+  char *new_argv[argc];
+  int new_argc;
+
+  for (int i = 1; i < argc; i++) {
+    std::string arg = argv[i];
+    if (arg.substr(0, 2) == "-v") {
+      const char* filename = argv[i]+2;
+      vcdfile = strcmp(filename, "-") == 0 ? stdout : fopen(filename, "w");
+      if (!vcdfile)
+        abort();
+    } else if (arg.substr(0, 2) == "-s")
+      random_seed = atoi(argv[i]+2);
+    else if (arg == "+verbose")
+      verbose = true;
+    else if (arg.substr(0, 12) == "+max-cycles=")
+      max_cycles = atoll(argv[i]+12);
+    else if (arg.substr(0, 7) == "+start=")
+      start = atoll(argv[i]+7);
+    else if (arg.substr(0, 12) == "+cycle-count")
+      print_cycles = true;
+  }
+
+  if (verbose)
+    fprintf(stderr, "using random seed %u\n", random_seed);
+
+  srand(random_seed);
+  srand48(random_seed);
+
+  Verilated::randReset(2);
+  Verilated::commandArgs(argc, argv);
+  VTestHarness *tile = new VTestHarness;
+
+#if VM_TRACE
+  Verilated::traceEverOn(true); // Verilator must compute traced signals
+  std::unique_ptr<VerilatedVcdFILE> vcdfd(new VerilatedVcdFILE(vcdfile));
+  std::unique_ptr<VerilatedVcdC> tfp(new VerilatedVcdC(vcdfd.get()));
+  if (vcdfile) {
+    tile->trace(tfp.get(), 99);  // Trace 99 levels of hierarchy
+    tfp->open("");
+  }
+#endif
+
+  new_argc = copy_argv(argc, argv, new_argv);
+  tsi = new tsi_t(new_argc, new_argv);
+
+  signal(SIGTERM, handle_sigterm);
+
+  // reset for several cycles to handle pipelined reset
+  for (int i = 0; i < 10; i++) {
+    tile->reset = 1;
+    tile->clock = 0;
+    tile->eval();
+    tile->clock = 1;
+    tile->eval();
+    tile->reset = 0;
+  }
+  done_reset = true;
+
+  while (!tsi->done() && !tile->io_success && trace_count < max_cycles) {
+    tile->clock = 0;
+    tile->eval();
+#if VM_TRACE
+    bool dump = tfp && trace_count >= start;
+    if (dump)
+      tfp->dump(static_cast<vluint64_t>(trace_count * 2));
+#endif
+
+    tile->clock = 1;
+    tile->eval();
+#if VM_TRACE
+    if (dump)
+      tfp->dump(static_cast<vluint64_t>(trace_count * 2 + 1));
+#endif
+    trace_count++;
+  }
+
+#if VM_TRACE
+  if (tfp)
+    tfp->close();
+#endif
+
+  if (vcdfile)
+    fclose(vcdfile);
+
+  if (tsi->exit_code())
+  {
+    fprintf(stderr, "*** FAILED *** (code = %d, seed %d) after %ld cycles\n", tsi->exit_code(), random_seed, trace_count);
+    ret = tsi->exit_code();
+  }
+  else if (trace_count == max_cycles)
+  {
+    fprintf(stderr, "*** FAILED *** (timeout, seed %d) after %ld cycles\n", random_seed, trace_count);
+    ret = 2;
+  }
+  else if (verbose || print_cycles)
+  {
+    fprintf(stderr, "Completed after %ld cycles\n", trace_count);
+  }
+
+  delete tsi;
+  delete tile;
+
+  return ret;
+}