// hard fault handler wrapper in assembly
// it extract the location of stack frame and pass it
// to handler in C as pointer.
__asm void hard_fault_handler_asm(void)
{
TST LR, #4
ITE EQ
MRSEQ R0, MSP
MRSNE R0, PSP
B __cpp(hard_fault_handler_c )
}
The second part of the handler is in C. Here, we demonstrate how the stacked register contents and the Fault Status registers can be accessed.
// 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]\n");
printf ("R0 = %x\n", stacked_r0);
printf ("R1 = %x\n", stacked_r1);
printf ("R2 = %x\n", stacked_r2);
printf ("R3 = %x\n", stacked_r3);
printf ("R12 = %x\n", stacked_r12);
printf ("LR = %x\n", stacked_lr);
printf ("PC = %x\n", stacked_pc);Cortex-M3 Troubleshooting Guide 425
printf ("PSR = %x\n", stacked_psr);
printf ("BFAR = %x\n", (*((volatile unsigned long *)(0xE000ED38))));
printf ("CFSR = %x\n", (*((volatile unsigned long *)(0xE000ED28))));
printf ("HFSR = %x\n", (*((volatile unsigned long *)(0xE000ED2C))));
printf ("DFSR = %x\n", (*((volatile unsigned long *)(0xE000ED30))));
printf ("AFSR = %x\n", (*((volatile unsigned long *)(0xE000ED3C))));
exit(0); // terminate
return;
}