/// <summary>
/// Mutually recursive functions that jump into each other's bodies.
/// </summary>
/// <returns></returns>
public static Program BuildProgram()
{
var prog = new ProgramBuilder();
var m = new ProcedureBuilder("even");
var r1 = m.Register(1);
m.BranchIf(m.Eq0(r1), "done");
m.Assign(r1, m.ISub(r1, 1));
m.Call("odd", 4);
m.Assign(r1, m.Not(r1));
m.Return();
m.Label("done");
m.Assign(r1, true);
m.Return();
prog.Add(m);
m = new ProcedureBuilder("odd");
r1 = m.Register(1);
m.BranchIf(m.Eq(r1, 1), "done");
m.Assign(r1, m.ISub(r1, 1));
m.Call("event", 4);
m.Assign(r1, m.Not(r1));
m.Return();
m.Label("done");
m.Assign(r1, true);
m.Return();
prog.Add(m);
return prog.BuildProgram();
}