diff --git a/riscv/execute.cc b/riscv/execute.cc
index 5c3fdf7..4d914b3 100644
--- a/riscv/execute.cc
+++ b/riscv/execute.cc
@@ -124,6 +124,10 @@ miss:
     }
 
     state.minstret += instret;
+    if (state.minstret > 1000000) {
+        printf("Reached limit of 1000000 instructions.\n");
+	exit(0);
+    }
     n -= instret;
   }
 }
diff --git a/riscv/insns/c_ebreak.h b/riscv/insns/c_ebreak.h
index a17200f..f06d8d9 100644
--- a/riscv/insns/c_ebreak.h
+++ b/riscv/insns/c_ebreak.h
@@ -1,2 +1,4 @@
 require_extension('C');
+
+exit(0);
 throw trap_breakpoint();
diff --git a/riscv/insns/sbreak.h b/riscv/insns/sbreak.h
index c22776c..d38bd22 100644
--- a/riscv/insns/sbreak.h
+++ b/riscv/insns/sbreak.h
@@ -1 +1,2 @@
+exit(0);
 throw trap_breakpoint();
diff --git a/riscv/mmu.h b/riscv/mmu.h
index b9948c5..bee1f8b 100644
--- a/riscv/mmu.h
+++ b/riscv/mmu.h
@@ -67,7 +67,8 @@ public:
       if (addr & (sizeof(type##_t)-1)) \
         throw trap_store_address_misaligned(addr); \
       reg_t vpn = addr >> PGSHIFT; \
-      if (likely(tlb_store_tag[vpn % TLB_ENTRIES] == vpn)) \
+      if (addr == 0x10000000) putchar(val), fflush(stdout); \
+      else if (likely(tlb_store_tag[vpn % TLB_ENTRIES] == vpn)) \
         *(type##_t*)(tlb_data[vpn % TLB_ENTRIES] + addr) = val; \
       else \
         store_slow_path(addr, sizeof(type##_t), (const uint8_t*)&val); \
diff --git a/riscv/processor.cc b/riscv/processor.cc
index 3b834c5..f407543 100644
--- a/riscv/processor.cc
+++ b/riscv/processor.cc
@@ -201,9 +201,9 @@ void processor_t::set_privilege(reg_t prv)
 
 void processor_t::take_trap(trap_t& t, reg_t epc)
 {
-  if (debug)
-    fprintf(stderr, "core %3d: exception %s, epc 0x%016" PRIx64 "\n",
-            id, t.name(), epc);
+  printf("core %3d: exception %s, epc 0x%016" PRIx64 "\n",
+         id, t.name(), epc);
+  exit(0);
 
   // by default, trap to M-mode, unless delegated to S-mode
   reg_t bit = t.cause();