这段查找硬件中断原因的代码，下面子函数获取的代码变量各是什么意思呢？（stacked_r0 这些等）
HardFault_Handler
                PROC
                        IMPORT hard_fault_handler_c
                        TST LR, #4   
                        ITE EQ   
                        MRSEQ R0, MSP   
                        MRSNE R0, PSP   
                        B hard_fault_handler_c   
                ENDP

// hard fault handler in C,   

// with stack frame location as input parameter   

void hard_fault_handler_c(unsigned int * hardfault_args)   

{   
        unsigned int stacked_r0;   
        unsigned int stacked_r1;   
        unsigned int stacked_r2;   
        unsigned int stacked_r3;   
        unsigned int stacked_r12;   
        unsigned int stacked_lr;   
        unsigned int stacked_pc;   
        unsigned int stacked_psr;             

        stacked_r0 = ((unsigned long) hardfault_args[0]);   
        stacked_r1 = ((unsigned long) hardfault_args[1]);   
        stacked_r2 = ((unsigned long) hardfault_args[2]);   
        stacked_r3 = ((unsigned long) hardfault_args[3]);   

        stacked_r12 = ((unsigned long) hardfault_args[4]);   
        stacked_lr = ((unsigned long) hardfault_args[5]);   
        stacked_pc = ((unsigned long) hardfault_args[6]);   
        stacked_psr = ((unsigned long) hardfault_args[7]);   

        printf ("[Hard fault handler] ");   
        printf ("R0 = %x ", stacked_r0);   
        printf ("R1 = %x ", stacked_r1);   
        printf ("R2 = %x ", stacked_r2);   
        printf ("R3 = %x ", stacked_r3);   
        printf ("R12 = %x ", stacked_r12);   
        printf ("LR = %x ", stacked_lr);   
        printf ("PC = %x ", stacked_pc);   
        printf ("PSR = %x ", stacked_psr);   
        printf ("BFAR = %x ", (*((volatile unsigned long *)(0xE000ED38))));
        printf ("CFSR = %x ", (*((volatile unsigned long *)(0xE000ED28))));
        printf ("HFSR = %x ", (*((volatile unsigned long *)(0xE000ED2C))));
        printf ("DFSR = %x ", (*((volatile unsigned long *)(0xE000ED30))));
        printf ("AFSR = %x ", (*((volatile unsigned long *)(0xE000ED3C))));
        while(1)
        {
                ;
        }
}