From 35c55a653c1e16c139f50040696aad7c8c67d4ef Mon Sep 17 00:00:00 2001
From: Anthony Pesch <inolen@gmail.com>
Date: Sun, 31 Jan 2016 03:19:12 -0800
Subject: [PATCH] warn on invalid memory read or write from a dynamic region

---
 src/hw/memory.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/hw/memory.cc b/src/hw/memory.cc
index fbb7f420..2b6ba401 100644
--- a/src/hw/memory.cc
+++ b/src/hw/memory.cc
@@ -547,6 +547,11 @@ inline INT Memory::ReadBytes(uint32_t addr) {
   }
 
   MemoryRegion &region = regions_[RegionIndex(page)];
+  if (!(region.*HANDLER)) {
+    LOG_WARNING("Unmapped read at 0x%08x", addr);
+    return 0;
+  }
+
   uint32_t region_offset = RegionOffset(page);
   return (region.*HANDLER)(region.ctx, region_offset + page_offset);
 }
@@ -563,6 +568,11 @@ inline void Memory::WriteBytes(uint32_t addr, INT value) {
   }
 
   MemoryRegion &region = regions_[RegionIndex(page)];
+  if (!(region.*HANDLER)) {
+    LOG_WARNING("Unmapped write at 0x%08x", addr);
+    return;
+  }
+
   uint32_t region_offset = RegionOffset(page);
   (region.*HANDLER)(region.ctx, region_offset + page_offset, value);
 }