exceptions.c

LED APPLICATION MCF51JM

/*
 * File:    exceptions.c
 * Purpose: Generic exception handling for ColdFire processors
 *
 */

#include "derivative.h"
#include "exceptions.h"
#include "startcf.h"

#define REGISTER_ABI __REGABI__


void _Entry(void);

/***********************************************************************/
/*
 *  Set NO_PRINTF to 0 in order the exceptions.c interrupt handler
 *  to output messages to the standard io. 
 * 
 */
#define NO_PRINTF    1

#if NO_PRINTF
#define VECTORDISPLAY(MESSAGE)                    asm { nop; };
#define VECTORDISPLAY2(MESSAGE,MESSAGE2)          asm { nop; };
#define VECTORDISPLAY3(MESSAGE,MESSAGE2,MESSAGE3) asm { nop; };
#else
#include <stdio.h>
#define VECTORDISPLAY(MESSAGE1)                    printf(MESSAGE1);
#define VECTORDISPLAY2(MESSAGE1,MESSAGE2)          printf(MESSAGE1,MESSAGE2);
#define VECTORDISPLAY3(MESSAGE1,MESSAGE2,MESSAGE3) printf(MESSAGE1,MESSAGE2,MESSAGE3);
#endif

#ifdef __cplusplus
extern "C" {
#endif

extern unsigned long far _SP_INIT[];

/***********************************************************************/
/*
 * Handling of the TRK ColdFire libs (printf support in Debugger Terminal) 
 * 
 * To enable this support:  
 * - Set CONSOLE_IO_SUPPORT  1 in this file; this will enable 
 *   TrapHandler_printf for the trap #14 exception.
 *
 * - Make sure the file console_io_cf.c is in your project. 
 *
 * - In the debugger make sure that in the Connection "Setup" dialog, 
 *   "Debug Options" property page, the check box 
 *   "Enable Terminal printf support" is set.
 *   
 *
 * 
 */
#define CONSOLE_IO_SUPPORT  0 

#if CONSOLE_IO_SUPPORT
asm void TrapHandler_printf(void) {
   HALT
   RTE
}
#endif                                                   

/***********************************************************************/
/*
 * This is the handler for all exceptions which are not common to all 
 * ColdFire Chips.  
 *
 * Called by mcf_exception_handler
 * 
 */
void derivative_interrupt(unsigned long vector)
{
   if (vector < 64 || vector > 192) {
      VECTORDISPLAY2("User Defined Vector #%d\n",vector);
   }
}

/***********************************************************************
 *
 * This is the exception handler for all  exceptions common to all 
 * chips ColdFire.  Most exceptions do nothing, but some of the more 
 * important ones are handled to some extent.
 *
 * Called by asm_exception_handler 
 *
 * The ColdFire family of processors has a simplified exception stack
 * frame that looks like the following:
 *
 *              3322222222221111 111111
 *              1098765432109876 5432109876543210
 *           8 +----------------+----------------+
 *             |         Program Counter         |
 *           4 +----------------+----------------+
 *             |FS/Fmt/Vector/FS|      SR        |
 *   SP -->  0 +----------------+----------------+
 *
 * The stack self-aligns to a 4-byte boundary at an exception, with
 * the FS/Fmt/Vector/FS field indicating the size of the adjustment
 * (SP += 0,1,2,3 bytes).
 *             31     28 27      26 25    18 17      16 15                                  0
 *           4 +---------------------------------------+------------------------------------+
 *             | Format | FS[3..2] | Vector | FS[1..0] |                 SR                 |
 *   SP -->  0 +---------------------------------------+------------------------------------+
 */ 
#define MCF5XXX_RD_SF_FORMAT(PTR)   \
   ((*((unsigned short *)(PTR)) >> 12) & 0x00FF)

#define MCF5XXX_RD_SF_VECTOR(PTR)   \
   ((*((unsigned short *)(PTR)) >>  2) & 0x00FF)

#define MCF5XXX_RD_SF_FS(PTR)    \
   ( ((*((unsigned short *)(PTR)) & 0x0C00) >> 8) | (*((unsigned short *)(PTR)) & 0x0003) )

#define MCF5XXX_SF_SR(PTR)    *(((unsigned short *)(PTR))+1)

#define MCF5XXX_SF_PC(PTR)    *((unsigned long *)(PTR)+1)

#define MCF5XXX_EXCEPTFMT     "%s -- PC = %#08X\n"


void mcf_exception_handler(void *framepointer) 
{
   volatile unsigned long exceptionStackFrame = (*(unsigned long *)(framepointer)); 
   volatile unsigned short stackFrameSR       = MCF5XXX_SF_SR(framepointer);  
   volatile unsigned short stackFrameWord     = (*(unsigned short *)(framepointer));  
   volatile unsigned long  stackFrameFormat   = (unsigned long)MCF5XXX_RD_SF_FORMAT(&stackFrameWord);
   volatile unsigned long  stackFrameFS       = (unsigned long)MCF5XXX_RD_SF_FS(&stackFrameWord);
   volatile unsigned long  stackFrameVector   = (unsigned long)MCF5XXX_RD_SF_VECTOR(&stackFrameWord);
   volatile unsigned long  stackFramePC       = MCF5XXX_SF_PC(framepointer);

   switch (stackFrameFormat)
   {
      case 4:
      case 5:
      case 6:
      case 7:
         break;
      default:
         VECTORDISPLAY3(MCF5XXX_EXCEPTFMT,"Illegal stack type", stackFramePC);
         break;
   }

   switch (stackFrameVector)
   {
   case 2:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Access Error", stackFramePC);
      switch (stackFrameFS)
      {
         case 4:
            VECTORDISPLAY("Error on instruction fetch\n");
            break;
         case 8:
            VECTORDISPLAY("Error on operand write\n");
            break;
         case 9:
            VECTORDISPLAY("Attempted write to write-protected space\n");
            break;
         case 12:
            VECTORDISPLAY("Error on operand read\n");
            break;
         default:
            VECTORDISPLAY("Reserved Fault Status Encoding\n");
            break;
      }
      break;
   case 3:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Address Error", stackFramePC);
      switch (stackFrameFS)
      {
         case 4:
            VECTORDISPLAY("Error on instruction fetch\n");
            break;
         case 8:
            VECTORDISPLAY("Error on operand write\n");
            break;
         case 9:
            VECTORDISPLAY("Attempted write to write-protected space\n");
            break;
         case 12:
            VECTORDISPLAY("Error on operand read\n");
            break;
         default:
            VECTORDISPLAY("Reserved Fault Status Encoding\n");
            break;
      }
      break;
   case 4:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Illegal instruction", stackFramePC);
      break;
   case 8:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Privilege violation", stackFramePC);
      break;
   case 9:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Trace Exception", stackFramePC);
      break;
   case 10:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Unimplemented A-Line Instruction", 	stackFramePC);
      break;
   case 11:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Unimplemented F-Line Instruction", 	stackFramePC);
      break;
   case 12:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Debug Interrupt", stackFramePC);
      break;
   case 14:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Format Error", stackFramePC);
      break;
   case 15:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Unitialized Interrupt", stackFramePC);
      break;
   case 24:
      VECTORDISPLAY3(MCF5XXX_EXCEPTFMT, "Spurious Interrupt", stackFramePC);
      break;
   case 25:
   case 26:
   case 27:
   case 28: