interp.c

这个是LINUX下的GDB调度工具的源码

	case 0xF8: case 0xF9: case 0xFA: case 0xFB:
	case 0xFC: case 0xFD: case 0xFE: case 0xFF:	/* bsr */	
	  cpu.gr[15] = pc;
	case 0xF0: case 0xF1: case 0xF2: case 0xF3:
	case 0xF4: case 0xF5: case 0xF6: case 0xF7:	/* br */
	  {
	    int disp;
	    disp = inst & 0x03FF;
	    if (inst & 0x0400)
	      disp |= 0xFFFFFC00;
	    pc += disp<<1;
	    bonus_cycles++;
	    needfetch = 1;
	  }
	  break;

	}

      if (tracing)
	fprintf (stderr, "\n");

      if (needfetch)   
	{
	  /* Do not let him fetch from a bad address! */
	  if (((uword)pc) >= cpu.asregs.msize)
	    {
	      if (issue_messages)
		fprintf (stderr, "PC loaded at 0x%x is outside of available memory! (0x%x)\n", oldpc, pc);
	      
	      cpu.asregs.exception = SIGSEGV;
	    }
	  else
	    {
	      ibuf = rlat (pc & 0xFFFFFFFC);
	      needfetch = 0;
	    }
	}
    }
  while (!cpu.asregs.exception);

  /* Hide away the things we've cached while executing.  */
  cpu.asregs.pc = pc;
  cpu.asregs.insts += insts;		/* instructions done ... */
  cpu.asregs.cycles += insts;		/* and each takes a cycle */
  cpu.asregs.cycles += bonus_cycles;	/* and extra cycles for branches */
  cpu.asregs.cycles += memops * memcycles;	/* and memop cycle delays */
  
  signal (SIGINT, sigsave);
}


int
sim_write (sd, addr, buffer, size)
     SIM_DESC sd;
     SIM_ADDR addr;
     unsigned char * buffer;
     int size;
{
  int i;
  init_pointers ();
  
  memcpy (& cpu.mem[addr], buffer, size);
  
  return size;
}

int
sim_read (sd, addr, buffer, size)
     SIM_DESC sd;
     SIM_ADDR addr;
     unsigned char * buffer;
     int size;
{
  int i;
  init_pointers ();
  
  memcpy (buffer, & cpu.mem[addr], size);
  
  return size;
}


int
sim_store_register (sd, rn, memory, length)
     SIM_DESC sd;
     int rn;
     unsigned char * memory;
     int length;
{
  init_pointers ();

  if (rn < NUM_MCORE_REGS && rn >= 0)
    {
      if (length == 4)
	{
	  long ival;
	  
	  /* misalignment safe */
	  ival = mcore_extract_unsigned_integer (memory, 4);
	  cpu.asints[rn] = ival;
	}

      return 4;
    }
  else
    return 0;
}

int
sim_fetch_register (sd, rn, memory, length)
     SIM_DESC sd;
     int rn;
     unsigned char * memory;
     int length;
{
  init_pointers ();
  
  if (rn < NUM_MCORE_REGS && rn >= 0)
    {
      if (length == 4)
	{
	  long ival = cpu.asints[rn];

	  /* misalignment-safe */
	  mcore_store_unsigned_integer (memory, 4, ival);
	}
      
      return 4;
    }
  else
    return 0;
}


int
sim_trace (sd)
     SIM_DESC sd;
{
  tracing = 1;
  
  sim_resume (sd, 0, 0);

  tracing = 0;
  
  return 1;
}

void
sim_stop_reason (sd, reason, sigrc)
     SIM_DESC sd;
     enum sim_stop * reason;
     int * sigrc;
{
  if (cpu.asregs.exception == SIGQUIT)
    {
      * reason = sim_exited;
      * sigrc = cpu.gr[PARM1];
    }
  else
    {
      * reason = sim_stopped;
      * sigrc = cpu.asregs.exception;
    }
}


int
sim_stop (sd)
     SIM_DESC sd;
{
  cpu.asregs.exception = SIGINT;
  return 1;
}


void
sim_info (sd, verbose)
     SIM_DESC sd;
     int verbose;
{
#ifdef WATCHFUNCTIONS
  int w, wcyc;
#endif
  double virttime = cpu.asregs.cycles / 36.0e6;

  callback->printf_filtered (callback, "\n\n# instructions executed  %10d\n",
			     cpu.asregs.insts);
  callback->printf_filtered (callback, "# cycles                 %10d\n",
			     cpu.asregs.cycles);
  callback->printf_filtered (callback, "# pipeline stalls        %10d\n",
			     cpu.asregs.stalls);
  callback->printf_filtered (callback, "# virtual time taken     %10.4f\n",
			     virttime);

#ifdef WATCHFUNCTIONS
  callback->printf_filtered (callback, "\nNumber of watched functions: %d\n",
			     ENDWL);

  wcyc = 0;
  
  for (w = 1; w <= ENDWL; w++)
    {
      callback->printf_filtered (callback, "WL = %s %8x\n",WLstr[w],WL[w]);
      callback->printf_filtered (callback, "  calls = %d, cycles = %d\n",
				 WLcnts[w],WLcyc[w]);
      
      if (WLcnts[w] != 0)
	callback->printf_filtered (callback,
				   "  maxcpc = %d, mincpc = %d, avecpc = %d\n",
				   WLmax[w],WLmin[w],WLcyc[w]/WLcnts[w]);
      wcyc += WLcyc[w];
    }
  
  callback->printf_filtered (callback,
			     "Total cycles for watched functions: %d\n",wcyc);
#endif
}

struct	aout
{
  unsigned char  sa_machtype[2];
  unsigned char  sa_magic[2];
  unsigned char  sa_tsize[4];
  unsigned char  sa_dsize[4];
  unsigned char  sa_bsize[4];
  unsigned char  sa_syms[4];
  unsigned char  sa_entry[4];
  unsigned char  sa_trelo[4];
  unsigned char  sa_drelo[4];
} aout;

#define	LONG(x)		(((x)[0]<<24)|((x)[1]<<16)|((x)[2]<<8)|(x)[3])
#define	SHORT(x)	(((x)[0]<<8)|(x)[1])

SIM_DESC
sim_open (kind, cb, abfd, argv)
     SIM_OPEN_KIND kind;
     host_callback * cb;
     struct bfd * abfd;
     char ** argv;
{
  int osize = sim_memory_size;
  myname = argv[0];
  callback = cb;
  
  if (kind == SIM_OPEN_STANDALONE)
    issue_messages = 1;
  
  /* Discard and reacquire memory -- start with a clean slate.  */
  sim_size (1);		/* small */
  sim_size (osize);	/* and back again */

  set_initial_gprs ();	/* Reset the GPR registers.  */
  
  /* Fudge our descriptor for now.  */
  return (SIM_DESC) 1;
}

void
sim_close (sd, quitting)
     SIM_DESC sd;
     int quitting;
{
  /* nothing to do */
}

SIM_RC
sim_load (sd, prog, abfd, from_tty)
     SIM_DESC sd;
     char * prog;
     bfd * abfd;
     int from_tty;
{
  /* Do the right thing for ELF executables; this turns out to be
     just about the right thing for any object format that:
       - we crack using BFD routines
       - follows the traditional UNIX text/data/bss layout
       - calls the bss section ".bss".   */

  extern bfd * sim_load_file (); /* ??? Don't know where this should live.  */
  bfd * prog_bfd;

  {
    bfd * handle;
    asection * s_bss;
    handle = bfd_openr (prog, 0);	/* could be "mcore" */
    
    if (!handle)
      {
	printf("``%s'' could not be opened.\n", prog);
	return SIM_RC_FAIL;
      }
    
    /* Makes sure that we have an object file, also cleans gets the 
       section headers in place.  */
    if (!bfd_check_format (handle, bfd_object))
      {
	/* wasn't an object file */
	bfd_close (handle);
	printf ("``%s'' is not appropriate object file.\n", prog);
	return SIM_RC_FAIL;
      }

    /* Look for that bss section.  */
    s_bss = bfd_get_section_by_name (handle, ".bss");
    
    if (!s_bss)
      {
	printf("``%s'' has no bss section.\n", prog);
	return SIM_RC_FAIL;
      }

    /* Appropriately paranoid would check that we have
       a traditional text/data/bss ordering within memory.  */

    /* figure the end of the bss section */
#if 0
    printf ("bss section at 0x%08x for 0x%08x bytes\n",
	    (unsigned long) bfd_get_section_vma (handle, s_bss),
	    (unsigned long) bfd_section_size (handle, s_bss));
#endif
    heap_ptr = ((unsigned long) bfd_get_section_vma (handle, s_bss)
		+ (unsigned long) bfd_section_size (handle, s_bss));

    /* Clean up after ourselves.  */
    bfd_close (handle);
    
    /* XXX: do we need to free the s_bss and handle structures? */
  }

  /* from sh -- dac */
  prog_bfd = sim_load_file (sd, myname, callback, prog, abfd,
                            sim_kind == SIM_OPEN_DEBUG,
                            0, sim_write);
  if (prog_bfd == NULL)
    return SIM_RC_FAIL;
  
  target_big_endian = bfd_big_endian (prog_bfd);
    
  if (abfd == NULL)
    bfd_close (prog_bfd);

  return SIM_RC_OK;
}

SIM_RC
sim_create_inferior (sd, prog_bfd, argv, env)
     SIM_DESC sd;
     struct bfd * prog_bfd;
     char ** argv;
     char ** env;
{
  char ** avp;
  int nargs = 0;
  int nenv = 0;
  int s_length;
  int l;
  unsigned long strings;
  unsigned long pointers;
  unsigned long hi_stack;


  /* Set the initial register set.  */
  l = issue_messages;
  issue_messages = 0;
  set_initial_gprs ();
  issue_messages = l;
  
  hi_stack = cpu.asregs.msize - 4;
  cpu.asregs.pc = bfd_get_start_address (prog_bfd);

  /* Calculate the argument and environment strings.  */
  s_length = 0;
  nargs = 0;
  avp = argv;
  while (avp && *avp)
    {
      l = strlen (*avp) + 1;	/* include the null */
      s_length += (l + 3) & ~3;	/* make it a 4 byte boundary */
      nargs++; avp++;
    }

  nenv = 0;
  avp = env;
  while (avp && *avp)
    {
      l = strlen (*avp) + 1;	/* include the null */
      s_length += (l + 3) & ~ 3;/* make it a 4 byte boundary */
      nenv++; avp++;
    }

  /* Claim some memory for the pointers and strings. */
  pointers = hi_stack - sizeof(word) * (nenv+1+nargs+1);
  pointers &= ~3;		/* must be 4-byte aligned */
  cpu.gr[0] = pointers;

  strings = cpu.gr[0] - s_length;
  strings &= ~3;		/* want to make it 4-byte aligned */
  cpu.gr[0] = strings;
  /* dac fix, the stack address must be 8-byte aligned! */
  cpu.gr[0] = cpu.gr[0] - cpu.gr[0] % 8;

  /* Loop through the arguments and fill them in.  */
  cpu.gr[PARM1] = nargs;
  if (nargs == 0)
    {
      /* No strings to fill in.  */
      cpu.gr[PARM2] = 0;
    }
  else
    {
      cpu.gr[PARM2] = pointers;
      avp = argv;
      while (avp && *avp)
	{
	  /* Save where we're putting it.  */
	  wlat (pointers, strings);

	  /* Copy the string.  */
	  l = strlen (* avp) + 1;
	  strcpy ((char *)(cpu.mem + strings), *avp);

	  /* Bump the pointers.  */
	  avp++;
	  pointers += 4;
	  strings += l+1;
	}
      
      /* A null to finish the list.  */
      wlat (pointers, 0);
      pointers += 4;
    }

  /* Now do the environment pointers.  */
  if (nenv == 0)
    {
      /* No strings to fill in.  */
      cpu.gr[PARM3] = 0;
    }
  else
    {
      cpu.gr[PARM3] = pointers;
      avp = env;
      
      while (avp && *avp)
	{
	  /* Save where we're putting it.  */
	  wlat (pointers, strings);

	  /* Copy the string.  */
	  l = strlen (* avp) + 1;
	  strcpy ((char *)(cpu.mem + strings), *avp);

	  /* Bump the pointers.  */
	  avp++;
	  pointers += 4;
	  strings += l+1;
	}
      
      /* A null to finish the list.  */
      wlat (pointers, 0);
      pointers += 4;
    }
  
  return SIM_RC_OK;
}

void
sim_kill (sd)
     SIM_DESC sd;
{
  /* nothing to do */
}

void
sim_do_command (sd, cmd)
     SIM_DESC sd;
     char * cmd;
{
  /* Nothing there yet; it's all an error.  */
  
  if (cmd != NULL)
    {
      char ** simargv = buildargv (cmd);
      
      if (strcmp (simargv[0], "watch") == 0)
	{
	  if ((simargv[1] == NULL) || (simargv[2] == NULL))
	    {
	      fprintf (stderr, "Error: missing argument to watch cmd.\n");
	      return;
	    }
	  
	  ENDWL++;
	  
	  WL[ENDWL] = strtol (simargv[2], NULL, 0);
	  WLstr[ENDWL] = strdup (simargv[1]);
	  fprintf (stderr, "Added %s (%x) to watchlist, #%d\n",WLstr[ENDWL],
		   WL[ENDWL], ENDWL);

	}
      else if (strcmp (simargv[0], "dumpmem") == 0)
	{
	  unsigned char * p;
	  FILE * dumpfile;

	  if (simargv[1] == NULL)
	    fprintf (stderr, "Error: missing argument to dumpmem cmd.\n");

	  fprintf (stderr, "Writing dumpfile %s...",simargv[1]);
	  
	  dumpfile = fopen (simargv[1], "w");
	  p = cpu.mem;
	  fwrite (p, cpu.asregs.msize-1, 1, dumpfile);
	  fclose (dumpfile);
	  
	  fprintf (stderr, "done.\n");
	}
      else if (strcmp (simargv[0], "clearstats") == 0)
	{
	  cpu.asregs.cycles = 0;
	  cpu.asregs.insts = 0;
	  cpu.asregs.stalls = 0;
	  ENDWL = 0;
	}
      else if (strcmp (simargv[0], "verbose") == 0)
	{
	  issue_messages = 2;
	}
      else
	{
	  fprintf (stderr,"Error: \"%s\" is not a valid M.CORE simulator command.\n",
		   cmd);
	}
    }
  else
    {
      fprintf (stderr, "M.CORE sim commands: \n");
      fprintf (stderr, "  watch <funcname> <addr>\n");
      fprintf (stderr, "  dumpmem <filename>\n");
      fprintf (stderr, "  clearstats\n");
      fprintf (stderr, "  verbose\n");
    }
}

void
sim_set_callbacks (ptr)
     host_callback * ptr;
{
  callback = ptr; 
}