diff --git a/conts/libl4/src/arch/arm/v5/mutex.S b/conts/libl4/src/arch/arm/v5/mutex.S
new file mode 100644
index 0000000..51969fe
--- /dev/null
+++ b/conts/libl4/src/arch/arm/v5/mutex.S
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2009 Bahadir Balban
+ */
+#include <l4lib/arch/arm/asm.h>
+#include <l4lib/mutex.h>
+
+/*
+ * These use the same lock word for both being granted
+ * exclusive access to the word, and for storing lock values.
+ */
+
+BEGIN_PROC(__l4_mutex_lock)
+	mov	r2, #-2
+1:
+	swp	r1, r2, [r0]
+	cmp	r1, r2
+	beq	1b
+
+	@ Grabbed the lock,
+	add	r1, r1, #1		@ now increment its value
+	str	r1, [r0]		@ Store and finish
+	cmp	r1, #L4_MUTEX_LOCKED	@ Have we locked it?
+	moveq	r0, #L4_MUTEX_SUCCESS
+	movne	r0, #L4_MUTEX_CONTENDED
+	mov 	pc, lr
+END_PROC(__l4_mutex_lock)
+
+
+BEGIN_PROC(__l4_mutex_unlock)
+	mov	r2, #-2
+	mov	r1, #L4_MUTEX_UNLOCKED
+1:
+	swp	r3, r2, [r0]
+	cmp	r3, r2
+	beq	1b
+
+	@ Grabbed the lock
+	str	r1, [r0]		@ Now store unlocked value and finish
+	mov	r0, r3			@ Get the value of contenders
+	mov 	pc, lr
+END_PROC(__l4_mutex_unlock)
+
diff --git a/conts/libl4/src/arch/arm/v5/mutex.c b/conts/libl4/src/arch/arm/v5/mutex.c
deleted file mode 100644
index fb8c648..0000000
--- a/conts/libl4/src/arch/arm/v5/mutex.c
+++ /dev/null
@@ -1,103 +0,0 @@
-/*
- * Copyright (C) 2009-2010 B Labs Ltd.
- * Author: Bahadir Balban
- */
-
-#include L4LIB_INC_ARCH(asm.h)
-#include <l4lib/mutex.h>
-#include <l4lib/types.h>
-#include INC_SUBARCH(irq.h)
-#include L4LIB_INC_ARCH(syslib.h)	/* for BUG/BUG_ON,  */
-
-/*
- * NOTES:
- *
- * Recap on swp:
- *
- * swp rx, ry, [rz]
- *
- * In one instruction:
- *
- * 1) Stores the value in ry into location pointed by rz.
- * 2) Loads the value in the location of rz into rx.
- * By doing so, in one instruction one can attempt to lock
- * a word, and discover whether it was already locked.
- *
- * Why use tid of thread to lock mutex instead of
- * a single lock value?
- *
- * Because in one atomic instruction, not only the locking attempt
- * should be able to indicate whether it is locked, but also
- * the contentions. A unified lock value would not be sufficient.
- * The only way to indicate a contended lock is to store the
- * unique TID of the locker.
- */
-
-/*
- * Any non-negative value that is a potential TID
- * (including 0) means mutex is locked.
- */
-
-
-int __l4_mutex_lock(void *m, l4id_t tid)
-{
-	unsigned int tmp;
-
-	__asm__ __volatile__(
-		"swp %0, %1, [%2]"
-		: "=r" (tmp)
-		: "r"(tid), "r" (m)
-		: "memory"
-	);
-
-	if (tmp == L4_MUTEX_UNLOCKED)
-		return L4_MUTEX_SUCCESS;
-
-	return L4_MUTEX_CONTENDED;
-}
-
-
-int __l4_mutex_unlock(void *m, l4id_t tid)
-{
-	unsigned int tmp, tmp2 = L4_MUTEX_UNLOCKED;
-
-	__asm__ __volatile__(
-		"swp %0, %1, [%2]"
-		: "=r" (tmp)
-		: "r" (tmp2), "r"(m)
-		: "memory"
-	);
-
-	BUG_ON(tmp == L4_MUTEX_UNLOCKED);
-
-	if (tmp == tid)
-		return L4_MUTEX_SUCCESS;
-
-	return L4_MUTEX_CONTENDED;
-}
-
-u8 l4_atomic_dest_readb(unsigned long *location)
-{
-#if 0
-	unsigned int tmp;
-	__asm__ __volatile__ (
-		"swpb	r0, r2, [r1] \n"
-		: "=r"(tmp)
-		: "r"(location), "r"(0)
-		: "memory"
-	);
-	return (u8)tmp;
-#endif
-
-	unsigned int tmp;
-       // unsigned long state;
-       // irq_local_disable_save(&state);
-
-        tmp = *location;
-        *location = 0;
-        
-        //irq_local_restore(state);
-
-        return (u8)tmp;
-
-}