纠正错误

mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

#define configMAX_SYSCALL_INTERRUPT_PRIORITY ( configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS) )

#define configPRIO_BITS       __NVIC_PRIO_BITS

#define __NVIC_PRIO_BITS          4U       /*!< STM32F4XX uses 4 Bits for the Priority Levels */

最后发现 5<<(8-4U)

4U unsigned int 4

解决方法 U去掉

编译器：：