diff --git a/Port/Cortex-M/port_cmx_s.c b/Port/Cortex-M/port_cmx_s.c
index ba135e06..405ee698 100644
--- a/Port/Cortex-M/port_cmx_s.c
+++ b/Port/Cortex-M/port_cmx_s.c
@@ -181,12 +181,12 @@ __LOOP          mov     rx, r1
                 cmp     rx, r1
                 bne     __LOOP
                 dmb
-                strh    r3, [r1, #2]
                 cmp     r3, #0
                 beq     __RESrx
                 ldr     rx, =mPendSV_FIFO_X
                 b       __OVERFLOW
-__RESrx         mov     rx, r12
+__RESrx         strh    r3, [r1, #2]
+                mov     rx, r12
                 #undef  rx
                 #endif
 /* FIFO溢出 */
@@ -377,12 +377,12 @@ void mPendSV_FIFOLoader(void *sv)
                "cmp     "sDefStr(rx)", r1 \n"
                "bne     __LOOP \n"
                "dmb \n"
-               "strh    r3, [r1, #2] \n"
                "cmp     r3, #0 \n"
                "beq     __RESrx \n"
                "ldr     "sDefStr(rx)", =mPendSV_FIFO_X \n"
                "b       __OVERFLOW \n"
-"__RESrx:       mov     "sDefStr(rx)", r12 \n"
+"__RESrx:       strh    r3, [r1, #2] \n"
+               "mov     "sDefStr(rx)", r12 \n"
                 #undef  rx
                 #endif
 /* FIFO溢出 */