diff --git a/src/sim/syscall_emul.cc b/src/sim/syscall_emul.cc
index 4cf17a266..8736176ed 100644
--- a/src/sim/syscall_emul.cc
+++ b/src/sim/syscall_emul.cc
@@ -889,7 +889,7 @@ setpgidFunc(SyscallDesc *desc, int callnum, Process *process,
         return 0;
     }
 
-    Process *matched_ph = NULL;
+    Process *matched_ph = nullptr;
     System *sysh = tc->getSystemPtr();
 
     // Retrieves process pointer from active/suspended thread contexts.
@@ -903,7 +903,7 @@ setpgidFunc(SyscallDesc *desc, int callnum, Process *process,
         }
     }
 
-    assert(matched_ph != NULL);
+    assert(matched_ph);
     matched_ph->setpgid((pgid == 0) ? matched_ph->pid() : pgid);
 
     return 0;
diff --git a/src/sim/syscall_emul.hh b/src/sim/syscall_emul.hh
index a0fb7e4ed..a1c3b2905 100644
--- a/src/sim/syscall_emul.hh
+++ b/src/sim/syscall_emul.hh
@@ -1484,7 +1484,7 @@ mmapImpl(SyscallDesc *desc, int num, Process *p, ThreadContext *tc,
             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) {