am29k-tdep.c

早期freebsd实现

	p += 4;
    }
  /* We've found the start of the function.  
   * Try looking for a tag word that indicates whether there is a
   * memory frame pointer and what the memory stack allocation is.
   * If one doesn't exist, try using a more exhaustive search of
   * the prologue.  For now we don't care about the argcount or
   * whether or not the routine is transparent.
   */
  if (examine_tag(p-4,&trans,NULL,&msize,&mfp_used)) /* Found a good tag */
      examine_prologue (p, &rsize, 0, 0);
  else 						/* No tag try prologue */
      examine_prologue (p, &rsize, &msize, &mfp_used);

  fci->rsize = rsize;
  fci->msize = msize;
  fci->flags = 0;
  if (mfp_used)
  	fci->flags |= MFP_USED;
  if (trans)
  	fci->flags |= TRANSPARENT;
  if (innermost_frame)
    {
      fci->saved_msp = read_register (MSP_REGNUM) + msize;
    }
  else
    {
      if (mfp_used)
  	 fci->saved_msp =
	      read_register_stack_integer (fci->frame + rsize - 4, 4);
      else
  	    fci->saved_msp = fci->next->saved_msp + msize;
    }
}

void
init_extra_frame_info (fci)
     struct frame_info *fci;
{
  if (fci->next == 0)
    /* Assume innermost frame.  May produce strange results for "info frame"
       but there isn't any way to tell the difference.  */
    init_frame_info (1, fci);
  else {
      /* We're in get_prev_frame_info.
         Take care of everything in init_frame_pc.  */
      ;
    }
}

void
init_frame_pc (fromleaf, fci)
     int fromleaf;
     struct frame_info *fci;
{
  fci->pc = (fromleaf ? SAVED_PC_AFTER_CALL (fci->next) :
	     fci->next ? FRAME_SAVED_PC (fci->next) : read_pc ());
  init_frame_info (fromleaf, fci);
}

/* Local variables (i.e. LOC_LOCAL) are on the memory stack, with their
   offsets being relative to the memory stack pointer (high C) or
   saved_msp (gcc).  */

CORE_ADDR
frame_locals_address (fi)
     struct frame_info *fi;
{
  if (fi->flags & MFP_USED) 
    return fi->saved_msp;
  else
    return fi->saved_msp - fi->msize;
}

/* Routines for reading the register stack.  The caller gets to treat
   the register stack as a uniform stack in memory, from address $gr1
   straight through $rfb and beyond.  */

/* Analogous to read_memory except the length is understood to be 4.
   Also, myaddr can be NULL (meaning don't bother to read), and
   if actual_mem_addr is non-NULL, store there the address that it
   was fetched from (or if from a register the offset within
   registers).  Set *LVAL to lval_memory or lval_register, depending
   on where it came from.  */
void
read_register_stack (memaddr, myaddr, actual_mem_addr, lval)
     CORE_ADDR memaddr;
     char *myaddr;
     CORE_ADDR *actual_mem_addr;
     enum lval_type *lval;
{
  long rfb = read_register (RFB_REGNUM);
  long rsp = read_register (RSP_REGNUM);

  /* If we don't do this 'info register' stops in the middle. */
  if (memaddr >= rstack_high_address) 
    {
      int val = -1;			/* a bogus value */
      /* It's in a local register, but off the end of the stack.  */
      int regnum = (memaddr - rsp) / 4 + LR0_REGNUM;
      if (myaddr != NULL)
	*(int*)myaddr = val;		/* Provide bogusness */
      supply_register(regnum,&val);	/* More bogusness */
      if (lval != NULL)
	*lval = lval_register;
      if (actual_mem_addr != NULL)
	*actual_mem_addr = REGISTER_BYTE (regnum);
    }
  else if (memaddr < rfb)
    {
      /* It's in a register.  */
      int regnum = (memaddr - rsp) / 4 + LR0_REGNUM;
      if (regnum < LR0_REGNUM || regnum > LR0_REGNUM + 127)
	error ("Attempt to read register stack out of range.");
      if (myaddr != NULL)
	read_register_gen (regnum, myaddr);
      if (lval != NULL)
	*lval = lval_register;
      if (actual_mem_addr != NULL)
	*actual_mem_addr = REGISTER_BYTE (regnum);
    }
  else
    {
      /* It's in the memory portion of the register stack.  */
      if (myaddr != NULL) 
	   read_memory (memaddr, myaddr, 4);
      if (lval != NULL)
	*lval = lval_memory;
      if (actual_mem_addr != NULL)
	*actual_mem_addr = memaddr;
    }
}

/* Analogous to read_memory_integer
   except the length is understood to be 4.  */
long
read_register_stack_integer (memaddr, len)
     CORE_ADDR memaddr;
     int len;
{
  long buf;
  read_register_stack (memaddr, &buf, NULL, NULL);
  SWAP_TARGET_AND_HOST (&buf, 4);
  return buf;
}

/* Copy 4 bytes from GDB memory at MYADDR into inferior memory
   at MEMADDR and put the actual address written into in
   *ACTUAL_MEM_ADDR.  */
static void
write_register_stack (memaddr, myaddr, actual_mem_addr)
     CORE_ADDR memaddr;
     char *myaddr;
     CORE_ADDR *actual_mem_addr;
{
  long rfb = read_register (RFB_REGNUM);
  long rsp = read_register (RSP_REGNUM);
  /* If we don't do this 'info register' stops in the middle. */
  if (memaddr >= rstack_high_address) 
    {
      /* It's in a register, but off the end of the stack.  */
      if (actual_mem_addr != NULL)
	*actual_mem_addr = NULL; 
    }
  else if (memaddr < rfb)
    {
      /* It's in a register.  */
      int regnum = (memaddr - rsp) / 4 + LR0_REGNUM;
      if (regnum < LR0_REGNUM || regnum > LR0_REGNUM + 127)
	error ("Attempt to read register stack out of range.");
      if (myaddr != NULL)
	write_register (regnum, *(long *)myaddr);
      if (actual_mem_addr != NULL)
	*actual_mem_addr = NULL;
    }
  else
    {
      /* It's in the memory portion of the register stack.  */
      if (myaddr != NULL)
	write_memory (memaddr, myaddr, 4);
      if (actual_mem_addr != NULL)
	*actual_mem_addr = memaddr;
    }
}

/* Find register number REGNUM relative to FRAME and put its
   (raw) contents in *RAW_BUFFER.  Set *OPTIMIZED if the variable
   was optimized out (and thus can't be fetched).  If the variable
   was fetched from memory, set *ADDRP to where it was fetched from,
   otherwise it was fetched from a register.

   The argument RAW_BUFFER must point to aligned memory.  */
void
get_saved_register (raw_buffer, optimized, addrp, frame, regnum, lvalp)
     char *raw_buffer;
     int *optimized;
     CORE_ADDR *addrp;
     FRAME frame;
     int regnum;
     enum lval_type *lvalp;
{
  struct frame_info *fi;
  CORE_ADDR addr;
  enum lval_type lval;

  if (frame == 0)
    return;

  fi = get_frame_info (frame);

  /* Once something has a register number, it doesn't get optimized out.  */
  if (optimized != NULL)
    *optimized = 0;
  if (regnum == RSP_REGNUM)
    {
      if (raw_buffer != NULL)
	*(CORE_ADDR *)raw_buffer = fi->frame;
      if (lvalp != NULL)
	*lvalp = not_lval;
      return;
    }
  else if (regnum == PC_REGNUM)
    {
      if (raw_buffer != NULL)
	*(CORE_ADDR *)raw_buffer = fi->pc;

      /* Not sure we have to do this.  */
      if (lvalp != NULL)
	*lvalp = not_lval;

      return;
    }
  else if (regnum == MSP_REGNUM)
    {
      if (raw_buffer != NULL)
	{
	  if (fi->next != NULL)
	    *(CORE_ADDR *)raw_buffer = fi->next->saved_msp;
	  else
	    *(CORE_ADDR *)raw_buffer = read_register (MSP_REGNUM);
	}
      /* The value may have been computed, not fetched.  */
      if (lvalp != NULL)
	*lvalp = not_lval;
      return;
    }
  else if (regnum < LR0_REGNUM || regnum >= LR0_REGNUM + 128)
    {
      /* These registers are not saved over procedure calls,
	 so just print out the current values.  */
      if (raw_buffer != NULL)
	*(CORE_ADDR *)raw_buffer = read_register (regnum);
      if (lvalp != NULL)
	*lvalp = lval_register;
      if (addrp != NULL)
	*addrp = REGISTER_BYTE (regnum);
      return;
    }
      
  addr = fi->frame + (regnum - LR0_REGNUM) * 4;
  if (raw_buffer != NULL)
    read_register_stack (addr, raw_buffer, &addr, &lval);
  if (lvalp != NULL)
    *lvalp = lval;
  if (addrp != NULL)
    *addrp = addr;
}


/* Discard from the stack the innermost frame,
   restoring all saved registers.  */

void
pop_frame ()
{
  FRAME frame = get_current_frame ();					      
  struct frame_info *fi = get_frame_info (frame);			      
  CORE_ADDR rfb = read_register (RFB_REGNUM);				      
  CORE_ADDR gr1 = fi->frame + fi->rsize;
  CORE_ADDR lr1;							      
  int i;

  /* If popping a dummy frame, need to restore registers.  */
  if (PC_IN_CALL_DUMMY (read_register (PC_REGNUM),
			read_register (SP_REGNUM),
			FRAME_FP (fi)))
    {
      int lrnum = LR0_REGNUM + DUMMY_ARG/4;
      for (i = 0; i < DUMMY_SAVE_SR128; ++i)
	write_register (SR_REGNUM (i + 128),read_register (lrnum++));
      for (i = 0; i < DUMMY_SAVE_SR160; ++i)
	write_register (SR_REGNUM(i+160), read_register (lrnum++));
      for (i = 0; i < DUMMY_SAVE_GREGS; ++i)
	write_register (RETURN_REGNUM + i, read_register (lrnum++));
      /* Restore the PCs.  */
      write_register(PC_REGNUM, read_register (lrnum++));
      write_register(NPC_REGNUM, read_register (lrnum));
    }

  /* Restore the memory stack pointer.  */
  write_register (MSP_REGNUM, fi->saved_msp);				      
  /* Restore the register stack pointer.  */				      
  write_register (GR1_REGNUM, gr1);
  /* Check whether we need to fill registers.  */			      
  lr1 = read_register (LR0_REGNUM + 1);				      
  if (lr1 > rfb)							      
    {									      
      /* Fill.  */							      
      int num_bytes = lr1 - rfb;
      int i;								      
      long word;							      
      write_register (RAB_REGNUM, read_register (RAB_REGNUM) + num_bytes);  
      write_register (RFB_REGNUM, lr1);				      
      for (i = 0; i < num_bytes; i += 4)				      
        {
	  /* Note: word is in host byte order.  */
          word = read_memory_integer (rfb + i, 4);
          write_register (LR0_REGNUM + ((rfb - gr1) % 0x80) + i / 4, word);					      
        }								      
    }
  flush_cached_frames ();						      
  set_current_frame (create_new_frame (0, read_pc()));		      
}

/* Push an empty stack frame, to record the current PC, etc.  */

void 
push_dummy_frame ()
{
  long w;
  CORE_ADDR rab, gr1;
  CORE_ADDR msp = read_register (MSP_REGNUM);
  int lrnum,  i, saved_lr0;
  

  /* Allocate the new frame. */ 
  gr1 = read_register (GR1_REGNUM) - DUMMY_FRAME_RSIZE;
  write_register (GR1_REGNUM, gr1);

  rab = read_register (RAB_REGNUM);
  if (gr1 < rab)
    {
      /* We need to spill registers.  */
      int num_bytes = rab - gr1;
      CORE_ADDR rfb = read_register (RFB_REGNUM);
      int i;
      long word;

      write_register (RFB_REGNUM, rfb - num_bytes);
      write_register (RAB_REGNUM, gr1);
      for (i = 0; i < num_bytes; i += 4)
	{
	  /* Note:  word is in target byte order.  */
	  read_register_gen (LR0_REGNUM + i / 4, &word);
	  write_memory (rfb - num_bytes + i, &word, 4);
	}
    }

  /* There are no arguments in to the dummy frame, so we don't need
     more than rsize plus the return address and lr1.  */
  write_register (LR0_REGNUM + 1, gr1 + DUMMY_FRAME_RSIZE + 2 * 4);

  /* Set the memory frame pointer.  */
  write_register (LR0_REGNUM + DUMMY_FRAME_RSIZE / 4 - 1, msp);

  /* Allocate arg_slop.  */
  write_register (MSP_REGNUM, msp - 16 * 4);

  /* Save registers.  */
  lrnum = LR0_REGNUM + DUMMY_ARG/4;
  for (i = 0; i < DUMMY_SAVE_SR128; ++i)
    write_register (lrnum++, read_register (SR_REGNUM (i + 128)));
  for (i = 0; i < DUMMY_SAVE_SR160; ++i)
    write_register (lrnum++, read_register (SR_REGNUM (i + 160)));
  for (i = 0; i < DUMMY_SAVE_GREGS; ++i)
    write_register (lrnum++, read_register (RETURN_REGNUM + i));
  /* Save the PCs.  */
  write_register (lrnum++, read_register (PC_REGNUM));
  write_register (lrnum, read_register (NPC_REGNUM));
}

reginv_com (args, fromtty)
     char       *args;
     int        fromtty;
{
   registers_changed();
   if (fromtty)
	printf_filtered("Gdb's register cache invalidated.\n");
}

/* We use this mostly for debugging gdb */
void
_initialize_29k()
{
  extern CORE_ADDR text_end;

  add_com ("reginv ", class_obscure, reginv_com, 
        "Invalidate gdb's internal register cache.");

  /* FIXME, there should be a way to make a CORE_ADDR variable settable. */
  add_show_from_set
    (add_set_cmd ("rstack_high_address", class_support, var_uinteger,
		  (char *)&rstack_high_address,
		  "Set top address in memory of the register stack.\n\
Attempts to access registers saved above this address will be ignored\n\
or will produce the value -1.", &setlist),
     &showlist);

  /* FIXME, there should be a way to make a CORE_ADDR variable settable. */
  add_show_from_set
    (add_set_cmd ("call_scratch_address", class_support, var_uinteger,
		  (char *)&text_end,
"Set address in memory where small amounts of RAM can be used when\n\
making function calls into the inferior.", &setlist),
     &showlist);
}