diff --git a/src/sim/syscall_emul.hh b/src/sim/syscall_emul.hh
--- a/src/sim/syscall_emul.hh
+++ b/src/sim/syscall_emul.hh
@@ -1486,7 +1486,7 @@
             return -EBADF;
         sim_fd = ffdp->getSimFD();
 
-        pmap = (decltype(pmap))mmap(NULL, length, PROT_READ, MAP_PRIVATE,
+        pmap = (decltype(pmap))mmap(nullptr, length, PROT_READ, MAP_PRIVATE,
                                     sim_fd, offset);
 
         if (pmap == (decltype(pmap))-1) {
# Node ID 74ef725af65802abab853930cc144f9740a314e8
# Parent  51fbcaa334179a10036242c3434818b8f449e99f
diff --git a/src/sim/syscall_emul.cc b/src/sim/syscall_emul.cc
--- a/src/sim/syscall_emul.cc
+++ b/src/sim/syscall_emul.cc
@@ -887,7 +887,7 @@
         return 0;
     }
 
-    Process *matched_ph = NULL;
+    Process *matched_ph = nullptr;
     System *sysh = tc->getSystemPtr();
 
     // Retrieves process pointer from active/suspended thread contexts.
@@ -901,7 +901,7 @@
         }
     }
 
-    assert(matched_ph != NULL);
+    assert(matched_ph);
     matched_ph->setpgid((pgid == 0) ? matched_ph->pid() : pgid);
 
     return 0;