Add prv_changed / v_changed fields to state

This tracks whether the privilege / virtual mode was changed by the
execution of the current instruction.

3 files changed, 8 insertions, 0 deletions

diff --git a/riscv/execute.cc b/riscv/execute.cc
index 591090b..4f5860b 100644
--- a/riscv/execute.cc
+++ b/riscv/execute.cc
@@ -226,6 +226,8 @@ void processor_t::step(size_t n)
     size_t instret = 0;
     reg_t pc = state.pc;
     mmu_t* _mmu = mmu;
+    state.prv_changed = false;
+    state.v_changed = false;
 
     #define advance_pc() \
       if (unlikely(invalid_pc(pc))) { \
diff --git a/riscv/processor.cc b/riscv/processor.cc
index ff64f5a..3126433 100644
--- a/riscv/processor.cc
+++ b/riscv/processor.cc
@@ -203,6 +203,8 @@ void state_t::reset(processor_t* const proc, reg_t max_isa)
 
   prv = prev_prv = PRV_M;
   v = prev_v = false;
+  prv_changed = false;
+  v_changed = false;
   csrmap[CSR_MISA] = misa = std::make_shared<misa_csr_t>(proc, CSR_MISA, max_isa);
   mstatus = std::make_shared<mstatus_csr_t>(proc, CSR_MSTATUS);
 
@@ -766,6 +768,8 @@ void processor_t::set_privilege(reg_t prv, bool virt)
   state.prev_v = state.v;
   state.prv = legalize_privilege(prv);
   state.v = virt && state.prv != PRV_M;
+  state.prv_changed = state.prv != state.prev_prv;
+  state.v_changed = state.v != state.prev_v;
 }
 
 const char* processor_t::get_privilege_string()
diff --git a/riscv/processor.h b/riscv/processor.h
index 1b00808..a2e4286 100644
--- a/riscv/processor.h
+++ b/riscv/processor.h
@@ -84,6 +84,8 @@ struct state_t
   std::unordered_map<reg_t, csr_t_p> csrmap;
   reg_t prv;    // TODO: Can this be an enum instead?
   reg_t prev_prv;
+  bool prv_changed;
+  bool v_changed;
   bool v;
   bool prev_v;
   misa_csr_t_p misa;