diff --git a/arch/alpha/alpha_tru64_process.cc b/arch/alpha/alpha_tru64_process.cc
index 1722b658e..a211e0ae8 100644
--- a/arch/alpha/alpha_tru64_process.cc
+++ b/arch/alpha/alpha_tru64_process.cc
@@ -877,6 +877,10 @@ class Tru64 {
         *configptr_ptr = config_addr;
         configptr_ptr.copyOut(xc->mem);
 
+        // Register this as a valid address range with the process
+        process->nxm_start = base_addr;
+        process->nxm_end = cur_addr;
+
         return 0;
     }
 
diff --git a/sim/process.cc b/sim/process.cc
index 7111e8733..c18b31da7 100644
--- a/sim/process.cc
+++ b/sim/process.cc
@@ -89,6 +89,7 @@ Process::Process(const string &nm,
     }
 
     mmap_start = mmap_end = 0;
+    nxm_start = nxm_end = 0;
     // other parameters will be initialized when the program is loaded
 }
 
diff --git a/sim/process.hh b/sim/process.hh
index 1ab43cd62..1c6c6b3fb 100644
--- a/sim/process.hh
+++ b/sim/process.hh
@@ -97,6 +97,10 @@ class Process : public SimObject
     Addr mmap_start;
     Addr mmap_end;
 
+    // Base of region for nxm data
+    Addr nxm_start;
+    Addr nxm_end;
+
     std::string prog_fname;	// file name
     Addr prog_entry;		// entry point (initial PC)
 
@@ -159,9 +163,14 @@ class Process : public SimObject
     bool validDataAddr(Addr addr)
     {
         return ((data_base <= addr && addr < brk_point) ||
+#ifdef FULLSYSTEM
                 ((stack_base - 16*1024*1024) <= addr && addr < stack_base) ||
+#else
+                (next_thread_stack_base <= addr && addr < stack_base) ||
+#endif
                 (text_base <= addr && addr < (text_base + text_size)) ||
-                (mmap_start <= addr && addr < mmap_end));
+                (mmap_start <= addr && addr < mmap_end) ||
+                (nxm_start <= addr && addr < nxm_end));
     }
 
     virtual void syscall(ExecContext *xc) = 0;
diff --git a/sim/syscall_emul.hh b/sim/syscall_emul.hh
index 51a075a28..69c17c330 100644
--- a/sim/syscall_emul.hh
+++ b/sim/syscall_emul.hh
@@ -412,6 +412,10 @@ mmapFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc)
         // user didn't give an address... pick one from our "mmap region"
         start = p->mmap_end;
         p->mmap_end += RoundUp<Addr>(length, VMPageSize);
+        if (p->nxm_start != 0) {
+            //If we have an nxm space, make sure we haven't colided
+            assert(p->mmap_end < p->nxm_start);
+        }
     }
 
     if (!(flags & OS::TGT_MAP_ANONYMOUS)) {