diff --git a/libcpu/arm/armv6/stack.c b/libcpu/arm/armv6/stack.c
index ceb04f0985..648ea7dbf5 100644
--- a/libcpu/arm/armv6/stack.c
+++ b/libcpu/arm/armv6/stack.c
@@ -26,54 +26,57 @@
 /*****************************/
 /* CPU Mode                  */
 /*****************************/
-#define USERMODE		0x10
-#define FIQMODE			0x11
-#define IRQMODE			0x12
-#define SVCMODE			0x13
-#define ABORTMODE		0x17
-#define UNDEFMODE		0x1b
-#define MODEMASK		0x1f
-#define NOINT			0xc0
+#define USERMODE        0x10
+#define FIQMODE         0x11
+#define IRQMODE         0x12
+#define SVCMODE         0x13
+#define ABORTMODE       0x17
+#define UNDEFMODE       0x1b
+#define MODEMASK        0x1f
+#define NOINT           0xc0
 
 /**
  * This function will initialize thread stack
  *
  * @param tentry the entry of thread
- * @param parameter the parameter of entry 
+ * @param parameter the parameter of entry
  * @param stack_addr the beginning stack address
  * @param texit the function will be called when thread exit
  *
  * @return stack address
  */
 rt_uint8_t *rt_hw_stack_init(void *tentry, void *parameter,
-	rt_uint8_t *stack_addr, void *texit)
+                             rt_uint8_t *stack_addr, void *texit)
 {
-	rt_uint32_t *stk;
+    rt_uint32_t *stk;
 
-	stk 	 = (rt_uint32_t*)stack_addr;
-	*(stk) 	 = (rt_uint32_t)tentry;			/* entry point */
-	*(--stk) = (rt_uint32_t)texit;			/* lr */
-	*(--stk) = 0;							/* r12 */
-	*(--stk) = 0;							/* r11 */
-	*(--stk) = 0;							/* r10 */
-	*(--stk) = 0;							/* r9 */
-	*(--stk) = 0;							/* r8 */
-	*(--stk) = 0;							/* r7 */
-	*(--stk) = 0;							/* r6 */
-	*(--stk) = 0;							/* r5 */
-	*(--stk) = 0;							/* r4 */
-	*(--stk) = 0;							/* r3 */
-	*(--stk) = 0;							/* r2 */
-	*(--stk) = 0;							/* r1 */
-	*(--stk) = (rt_uint32_t)parameter;		/* r0 : argument */
+    stack_addr += sizeof(rt_uint32_t);
+    stack_addr  = (rt_uint8_t *)RT_ALIGN_DOWN((rt_uint32_t)stack_addr, 8);
+    stk      = (rt_uint32_t *)stack_addr;
 
-	/* cpsr */
-	if ((rt_uint32_t)tentry & 0x01)
-		*(--stk) = SVCMODE | 0x20;			/* thumb mode */
-	else
-		*(--stk) = SVCMODE;					/* arm mode   */
+    *(--stk) = (rt_uint32_t)tentry;         /* entry point */
+    *(--stk) = (rt_uint32_t)texit;          /* lr */
+    *(--stk) = 0xdeadbeef;                  /* r12 */
+    *(--stk) = 0xdeadbeef;                  /* r11 */
+    *(--stk) = 0xdeadbeef;                  /* r10 */
+    *(--stk) = 0xdeadbeef;                  /* r9 */
+    *(--stk) = 0xdeadbeef;                  /* r8 */
+    *(--stk) = 0xdeadbeef;                  /* r7 */
+    *(--stk) = 0xdeadbeef;                  /* r6 */
+    *(--stk) = 0xdeadbeef;                  /* r5 */
+    *(--stk) = 0xdeadbeef;                  /* r4 */
+    *(--stk) = 0xdeadbeef;                  /* r3 */
+    *(--stk) = 0xdeadbeef;                  /* r2 */
+    *(--stk) = 0xdeadbeef;                  /* r1 */
+    *(--stk) = (rt_uint32_t)parameter;      /* r0 : argument */
 
-	/* return task's current stack address */
-	return (rt_uint8_t *)stk;
+    /* cpsr */
+    if ((rt_uint32_t)tentry & 0x01)
+        *(--stk) = SVCMODE | 0x20;          /* thumb mode */
+    else
+        *(--stk) = SVCMODE;                 /* arm mode   */
+
+    /* return task's current stack address */
+    return (rt_uint8_t *)stk;
 }