triggers: Let mcontrol.match be default (0/equal) if maskmax is 0

riscv/triggers.cc

@@ -171,7 +171,7 @@ void mcontrol_t::tdata1_write(processor_t * const proc, const reg_t val, const b
   timing = legalize_timing(val, MCONTROL_TIMING, MCONTROL_SELECT, MCONTROL_EXECUTE, MCONTROL_LOAD);
   action = legalize_action(val, MCONTROL_ACTION, CSR_MCONTROL_DMODE(xlen));
   chain = allow_chain ? get_field(val, MCONTROL_CHAIN) : 0;
-  match = legalize_match(get_field(val, MCONTROL_MATCH));
+  match = legalize_match(get_field(val, MCONTROL_MATCH), maskmax);
   m = get_field(val, MCONTROL_M);
   s = proc->extension_enabled_const('S') ? get_field(val, CSR_MCONTROL_S) : 0;
   u = proc->extension_enabled_const('U') ? get_field(val, CSR_MCONTROL_U) : 0;
@@ -244,11 +244,11 @@ std::optional<match_result_t> mcontrol_common_t::detect_memory_access_match(proc
   return std::nullopt;
 }
 
-mcontrol_common_t::match_t mcontrol_common_t::legalize_match(reg_t val) noexcept
+mcontrol_common_t::match_t mcontrol_common_t::legalize_match(reg_t val, reg_t maskmax) noexcept
 {
   switch (val) {
+    case MATCH_NAPOT: if (maskmax == 0) return MATCH_EQUAL;
     case MATCH_EQUAL:
-    case MATCH_NAPOT:
     case MATCH_GE:
     case MATCH_LT:
     case MATCH_MASK_LOW:
@@ -294,13 +294,14 @@ void mcontrol6_t::tdata1_write(processor_t * const proc, const reg_t val, const
   auto xlen = proc->get_const_xlen();
   assert(get_field(val, CSR_MCONTROL6_TYPE(xlen)) == CSR_TDATA1_TYPE_MCONTROL6);
   dmode = get_field(val, CSR_MCONTROL6_DMODE(xlen));
+  const reg_t maskmax6 = xlen - 1;
   vs = get_field(val, CSR_MCONTROL6_VS);
   vu = get_field(val, CSR_MCONTROL6_VU);
   hit = hit_t(2 * get_field(val, CSR_MCONTROL6_HIT1) + get_field(val, CSR_MCONTROL6_HIT0)); // 2-bit field {hit1,hit0}
   select = get_field(val, CSR_MCONTROL6_SELECT);
   action = legalize_action(val, CSR_MCONTROL6_ACTION, CSR_MCONTROL6_DMODE(xlen));
   chain = allow_chain ? get_field(val, CSR_MCONTROL6_CHAIN) : 0;
-  match = legalize_match(get_field(val, CSR_MCONTROL6_MATCH));
+  match = legalize_match(get_field(val, CSR_MCONTROL6_MATCH), maskmax6);
   m = get_field(val, CSR_MCONTROL6_M);
   s = proc->extension_enabled_const('S') ? get_field(val, CSR_MCONTROL6_S) : 0;
   u = proc->extension_enabled_const('U') ? get_field(val, CSR_MCONTROL6_U) : 0;

riscv/triggers.h

@@ -221,7 +221,7 @@ private:
   bool simple_match(unsigned xlen, reg_t value) const;
 
 protected:
-  static match_t legalize_match(reg_t val) noexcept;
+  static match_t legalize_match(reg_t val, reg_t maskmax) noexcept;
   static bool legalize_timing(reg_t val, reg_t timing_mask, reg_t select_mask, reg_t execute_mask, reg_t load_mask) noexcept;
   bool dmode = false;
   action_t action = ACTION_DEBUG_EXCEPTION;