diff --git a/code/test/start.S b/code/test/start.S
index 52911f8..d79b2f4 100644
--- a/code/test/start.S
+++ b/code/test/start.S
@@ -198,6 +198,21 @@ GetInt:
 	j	$31
 	.end GetInt
 
+    .globl ThreadCreate
+    .ent   ThreadCreate
+ThreadCreate:
+    addiu $2,$0,SC_ThreadCreate
+	syscall
+	j	$31
+	.end ThreadCreate
+
+    .globl ThreadExit
+    .ent   ThreadExit
+ThreadExit:
+    addiu $2,$0,SC_ThreadExit
+	syscall
+	j	$31
+	.end ThreadExit
     
 #endif
 
diff --git a/code/userprog/exception.cc b/code/userprog/exception.cc
index 9177801..c4d751e 100644
--- a/code/userprog/exception.cc
+++ b/code/userprog/exception.cc
@@ -208,6 +208,14 @@ ExceptionHandler (ExceptionType which)
              machine->WriteMem(addr,sizeof(n),n);
              break;
           }
+        case SC_ThreadCreate:
+          {
+            break;
+          }
+        case SC_ThreadExit:
+          {
+            break;
+          }
         #endif
 		default:
 		  {
diff --git a/code/userprog/syscall.h b/code/userprog/syscall.h
index 96c9d33..94c598a 100644
--- a/code/userprog/syscall.h
+++ b/code/userprog/syscall.h
@@ -38,6 +38,8 @@
 #define SC_GetString    14
 #define SC_PutInt       15
 #define SC_GetInt       16
+#define SC_ThreadCreate 17
+#define SC_ThreadExit   18
 #endif
 #ifdef IN_USER_MODE
 
@@ -144,6 +146,8 @@ char GetChar();
 void GetString(char *s, int n );
 void PutInt(int n);  
 void GetInt( int * n);
+int ThreadCreate(void f(void * args), void * args);
+void ThreadExit(void);
 
 #endif // CHANGED