minimal change from https://zipcpu.com/tutorial/ex-04-reqwalker.tgz

wb-tut4/sim/top.cc

@@ -0,0 +1,118 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "Vtop.h"
+#include "verilated.h"
+#include "verilated_vcd_c.h"
+
+int	tickcount = 0;
+Vtop	*tb;
+VerilatedVcdC	*tfp;
+
+void	tick(void) {
+   tickcount++;
+
+   tb->eval();
+   if (tfp)
+      tfp->dump(tickcount * 10 - 2);
+   tb->i_clk = 1;
+   tb->eval();
+   if (tfp)
+      tfp->dump(tickcount * 10);
+   tb->i_clk = 0;
+   tb->eval();
+   if (tfp) {
+      tfp->dump(tickcount * 10 + 5);
+      tfp->flush();
+   }
+}
+
+unsigned wb_read(unsigned a) {
+   tb->i_cyc = tb->i_stb = 1;
+   tb->i_we  = 0;
+   tb->eval();
+   tb->i_addr= a;
+   // Make the request
+   while(tb->o_stall)
+      tick();
+   tick();
+   tb->i_stb = 0;
+   // Wait for the ACK
+   while(!tb->o_ack)
+      tick();
+   // Idle the bus, and read the response
+   tb->i_cyc = 0;
+   return tb->o_data;
+}
+
+void wb_write(unsigned a, unsigned v) {
+   tb->i_cyc = tb->i_stb = 1;
+   tb->i_we  = 1;
+   tb->eval();
+   tb->i_addr= a;
+   tb->i_data= v;
+   // if busy, keep ticking
+   while(tb->o_stall)
+      tick();
+   // Then, make the bus request 
+   tick();
+   // and pull stb down
+   tb->i_stb = 0;
+   // Wait for the acknowledgement
+   while(!tb->o_ack)
+      tick();
+   // Idle the bus and return
+   tb->i_cyc = tb->i_stb = 0;
+}
+
+int main(int argc, char **argv) {
+   int	last_led, last_state = 0, state = 0;
+
+   // Call commandArgs first!
+   Verilated::commandArgs(argc, argv);
+
+   // Instantiate our design
+   tb = new Vtop;
+
+   // Generate a trace
+   Verilated::traceEverOn(true);
+   tfp = new VerilatedVcdC;
+   tb->trace(tfp, 99);
+   tfp->open("build/waveform.vcd");
+
+   last_led = tb->o_led;
+
+   // Read from the current state
+   printf("Initial state is: 0x%02x\n",
+         wb_read(0));
+
+   for(int cycle=0; cycle<2; cycle++) {
+      // Wait five clocks
+      for(int i=0; i<5; i++)
+         tick();
+
+      // Start the LEDs cycling
+      wb_write(0,0);
+      tick();
+
+      while((state = wb_read(0))!=0) {
+         if ((state != last_state)
+               ||(tb->o_led != last_led)) {
+            printf("%6d: State #%2d ",
+                  tickcount, state);
+            for(int j=0; j<6; j++) {
+               if(tb->o_led & (1<<j))
+                  printf("O");
+               else
+                  printf("-");
+            } printf("\n");
+         } tick();
+
+         last_state = state;
+         last_led = tb->o_led;
+      }
+   }
+
+   tfp->close();
+   delete tfp;
+   delete tb;
+}

wb-tut4/sim/top.sby

@@ -0,0 +1,13 @@
+[options]
+mode prove
+
+[engines]
+smtbmc
+
+[script]
+read -formal *.v
+prep -top top
+
+[files]
+rtl/top.v
+rtl/clk_gen.v