source: rtems/bsps/m68k/shared/fpsp/rtems_fpsp.c

#include <rtems/score/cpu.h>

/*
 * User exception handlers
 */
CPU_ISR_raw_handler M68040FPSPUserExceptionHandlers[9];

/*
 * Intercept requests to install an exception handler.
 * FPSP exceptions get special treatment.
 */
static int
FPSP_install_raw_handler(
  uint32_t vector,
  CPU_ISR_raw_handler new_handler,
  CPU_ISR_raw_handler *old_handler
)
{
  int fpspVector;

  switch (vector) {
  default:      return 0;       /* Non-FPSP vector */
  case 11:      fpspVector = 0; break;  /* F-line */
  case 48:      fpspVector = 1; break;  /* BSUN */
  case 49:      fpspVector = 2; break;  /* INEXACT */
  case 50:      fpspVector = 3; break;  /* DIVIDE-BY-ZERO */
  case 51:      fpspVector = 4; break;  /* UNDERFLOW */
  case 52:      fpspVector = 5; break;  /* OPERAND ERROR */
  case 53:      fpspVector = 6; break;  /* OVERFLOW */
  case 54:      fpspVector = 7; break;  /* SIGNALLING NAN */
  case 55:      fpspVector = 8; break;  /* UNIMPLEMENTED DATA TYPE */
  }
  *old_handler = M68040FPSPUserExceptionHandlers[fpspVector];
  M68040FPSPUserExceptionHandlers[fpspVector] = new_handler;
  return 1;
}

/*
 *  Exception handlers provided by FPSP package.
 */
extern void _fpspEntry_fline(void);
extern void _fpspEntry_bsun(void);
extern void _fpspEntry_inex(void);
extern void _fpspEntry_dz(void);
extern void _fpspEntry_unfl(void);
extern void _fpspEntry_ovfl(void);
extern void _fpspEntry_operr(void);
extern void _fpspEntry_snan(void);
extern void _fpspEntry_unsupp(void);

/*
 * Attach floating point exception vectors to M68040FPSP entry points
 *
 *  NOTE: Uses M68K rather than M68040 in the name so all CPUs having
 *        an FPSP can share the same code in RTEMS proper.
 */
void
M68KFPSPInstallExceptionHandlers (void)
{
  static struct {
    int  vector_number;
    void  (*handler)(void);
  } fpspHandlers[] = {
    { 11,  _fpspEntry_fline },
    { 48,  _fpspEntry_bsun },
    { 49,  _fpspEntry_inex },
    { 50,  _fpspEntry_dz },
    { 51,  _fpspEntry_unfl },
    { 52,  _fpspEntry_operr },
    { 53,  _fpspEntry_ovfl },
    { 54,  _fpspEntry_snan },
    { 55,  _fpspEntry_unsupp },
  };
  int i;
  CPU_ISR_raw_handler oldHandler;

  for (i = 0 ; i < sizeof fpspHandlers / sizeof fpspHandlers[0] ; i++) {
    _CPU_ISR_install_raw_handler(fpspHandlers[i].vector_number, fpspHandlers[i].handler, &oldHandler);
      M68040FPSPUserExceptionHandlers[i] = oldHandler;
  }
  _FPSP_install_raw_handler = FPSP_install_raw_handler;
}