FreeRTOS 和 RT-Thread 功能差别对比

临界区

FreeRTOS：

非中断的临界区，根据优先级关中断，不会把所有中断都关了；使用了一个变量记录进临界区的次数，保证嵌套不出问题

void vPortEnterCritical( void ) // 进入临界区
{
    portDISABLE_INTERRUPTS();
    uxCriticalNesting++;

    /* This is not the interrupt safe version of the enter critical function so
    assert() if it is being called from an interrupt context.  Only API
    functions that end in "FromISR" can be used in an interrupt.  Only assert if
    the critical nesting count is 1 to protect against recursive calls if the
    assert function also uses a critical section. */
    if( uxCriticalNesting == 1 )
    {
        configASSERT( ( portNVIC_INT_CTRL_REG & portVECTACTIVE_MASK ) == 0 );
    }
}

#define portDISABLE_INTERRUPTS() \

{ \

__set_BASEPRI( configMAX_SYSCALL_INTERRUPT_PRIORITY ); \

__DSB(); \

__ISB(); \

}

/*-----------------------------------------------------------*/

void vPortExitCritical( void ) // 退出临界区
{
    configASSERT( uxCriticalNesting );
    uxCriticalNesting--;
    if( uxCriticalNesting == 0 )
    {
        portENABLE_INTERRUPTS();
    }
}

中断的临界区，先读取中断状态（保证嵌套不会有问题），再根据优先级关中断；最后根据之前读取的中断状态恢复中断

uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR(); // 进入临界区

#define portSET_INTERRUPT_MASK_FROM_ISR()        __get_BASEPRI(); portDISABLE_INTERRUPTS()

portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus ); // 退出临界区

RT-Thread：关闭所有中断