diff --git a/src/ch32v30x_it.c b/src/ch32v30x_it.c
index 389c795..34734b1 100644
--- a/src/ch32v30x_it.c
+++ b/src/ch32v30x_it.c
@@ -69,8 +69,12 @@ __IRQ_WEAK void NMI_Handler(void) {
 __IRQ_NAKED void SysTick_Handler(void) {
     /* Use naked function to generate a short call, without causing stack unbalance. */
     asm volatile(
-        "li t0, 0xE000F004\n" /* Clear SysTick->SR */
-        "sw zero, 0(t0)\n"
+        "addi sp, sp, -4\n"     /* Push */
+        "sw t0, 4(sp)\n"        /* Save t0 on stack */
+        "li t0, 0xE000F004\n"   /* SysTick->SR */
+        "sw zero, 0(t0)\n"      /* Write 0 to clear */
+        "lw t0, 4(sp)\n"        /* Restore t0 from stack */
+        "addi sp, sp, 4\n"      /* Pop */
         "j freertos_risc_v_mtimer_interrupt_handler"
     );
 }