Only perform norvc for boot section only. Sometimes this can be "leaky." and...

Only perform norvc for boot section only.  Sometimes this can be "leaky." and flow outside of the boot function.

ch32v003fun/ch32v003fun.c

@@ -720,6 +720,7 @@ void InterruptVectorDefault()
 {
 	asm volatile( "\n\
 	.align  2\n\
+	.option   push;\n\
 	.option   norvc;\n\
 	j handle_reset\n\
 	.word   0\n\
@@ -760,7 +761,8 @@ void InterruptVectorDefault()
 	.word   TIM1_UP_IRQHandler        /* TIM1 Update */                    \n\
 	.word   TIM1_TRG_COM_IRQHandler   /* TIM1 Trigger and Commutation */   \n\
 	.word   TIM1_CC_IRQHandler        /* TIM1 Capture Compare */           \n\
-	.word   TIM2_IRQHandler           /* TIM2 */                           \n");
+	.word   TIM2_IRQHandler           /* TIM2 */                           \n\
+	.option   pop;\n");
 }
 
 void handle_reset()