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/* Target-machine dependent code for Zilog Z8000, for GDB.

   Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 2 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program; if not, write to the Free Software

   Foundation, Inc., 59 Temple Place - Suite 330,

   Boston, MA 02111-1307, USA.  */

/*

   Contributed by Steve Chamberlain

   sac@cygnus.com

 */

#include "defs.h"

#include "frame.h"

#include "obstack.h"

#include "symtab.h"

#include "gdbcmd.h"

#include "gdbtypes.h"

#include "dis-asm.h"

#include "gdbcore.h"

#include "value.h" /* For read_register() */

static int read_memory_pointer (CORE_ADDR x);

/* Return the saved PC from this frame.

   If the frame has a memory copy of SRP_REGNUM, use that.  If not,

   just use the register SRP_REGNUM itself.  */

CORE_ADDR

z8k_frame_saved_pc (frame)

     struct frame_info *frame;

{

  return read_memory_pointer (frame->frame + (BIG ? 4 : 2));

}

#define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))

#define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))

#define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)

#define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)

#define IS_SUB2_SP(x) (x==0x1b87)

#define IS_MOVK_R5(x) (x==0x7905)

#define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)

#define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))

/* work out how much local space is on the stack and

   return the pc pointing to the first push */

static CORE_ADDR

skip_adjust (pc, size)

     CORE_ADDR pc;

     int *size;

{

  *size = 0;

  if (IS_PUSH_FP (read_memory_short (pc))

      && IS_MOV_SP_FP (read_memory_short (pc + 2)))

    {

      /* This is a function with an explict frame pointer */

      pc += 4;

      *size += 2;               /* remember the frame pointer */

    }

  /* remember any stack adjustment */

  if (IS_SUB_SP (read_memory_short (pc)))

    {

      *size += read_memory_short (pc + 2);

      pc += 4;

    }

  return pc;

}

static CORE_ADDR examine_frame PARAMS ((CORE_ADDR, CORE_ADDR * regs, CORE_ADDR));

static CORE_ADDR

examine_frame (pc, regs, sp)

     CORE_ADDR pc;

     CORE_ADDR *regs;

     CORE_ADDR sp;

{

  int w = read_memory_short (pc);

  int offset = 0;

  int regno;

  for (regno = 0; regno < NUM_REGS; regno++)

    regs[regno] = 0;

  while (IS_PUSHW (w) || IS_PUSHL (w))

    {

      /* work out which register is being pushed to where */

      if (IS_PUSHL (w))

        {

          regs[w & 0xf] = offset;

          regs[(w & 0xf) + 1] = offset + 2;

          offset += 4;

        }

      else

        {

          regs[w & 0xf] = offset;

          offset += 2;

        }

      pc += 2;

      w = read_memory_short (pc);

    }

  if (IS_MOVE_FP (w))

    {

      /* We know the fp */

    }

  else if (IS_SUB_SP (w))

    {

      /* Subtracting a value from the sp, so were in a function

         which needs stack space for locals, but has no fp.  We fake up

         the values as if we had an fp */

      regs[FP_REGNUM] = sp;

    }

  else

    {

      /* This one didn't have an fp, we'll fake it up */

      regs[SP_REGNUM] = sp;

    }

  /* stack pointer contains address of next frame */

  /*  regs[fp_regnum()] = fp; */

  regs[SP_REGNUM] = sp;

  return pc;

}

CORE_ADDR

z8k_skip_prologue (start_pc)

     CORE_ADDR start_pc;

{

  CORE_ADDR dummy[NUM_REGS];

  return examine_frame (start_pc, dummy, 0);

}

CORE_ADDR

z8k_addr_bits_remove (addr)

     CORE_ADDR addr;

{

  return (addr & PTR_MASK);

}

static int

read_memory_pointer (CORE_ADDR x)

{

  return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);

}

CORE_ADDR

z8k_frame_chain (thisframe)

     struct frame_info *thisframe;

{

  if (thisframe->prev == 0)

    {

      /* This is the top of the stack, let's get the sp for real */

    }

  if (!inside_entry_file (thisframe->pc))

    {

      return read_memory_pointer (thisframe->frame);

    }

  return 0;

}

void

init_frame_pc ()

{

  abort ();

}

/* Put here the code to store, into a struct frame_saved_regs,

   the addresses of the saved registers of frame described by FRAME_INFO.

   This includes special registers such as pc and fp saved in special

   ways in the stack frame.  sp is even more special:

   the address we return for it IS the sp for the next frame.  */

void

z8k_frame_init_saved_regs (frame_info)

     struct frame_info *frame_info;

{

  CORE_ADDR pc;

  int w;

  frame_saved_regs_zalloc (frame_info);

  pc = get_pc_function_start (frame_info->pc);

  /* wander down the instruction stream */

  examine_frame (pc, frame_info->saved_regs, frame_info->frame);

}

void

z8k_push_dummy_frame ()

{

  abort ();

}

int

gdb_print_insn_z8k (memaddr, info)

     bfd_vma memaddr;

     disassemble_info *info;

{

  if (BIG)

    return print_insn_z8001 (memaddr, info);

  else

    return print_insn_z8002 (memaddr, info);

}

/* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or

   is not the address of a valid instruction, the address of the next

   instruction beyond ADDR otherwise.  *PWORD1 receives the first word

   of the instruction. */

CORE_ADDR

NEXT_PROLOGUE_INSN (addr, lim, pword1)

     CORE_ADDR addr;

     CORE_ADDR lim;

     short *pword1;

{

  char buf[2];

  if (addr < lim + 8)

    {

      read_memory (addr, buf, 2);

      *pword1 = extract_signed_integer (buf, 2);

      return addr + 2;

    }

  return 0;

}

#if 0

/* Put here the code to store, into a struct frame_saved_regs,

   the addresses of the saved registers of frame described by FRAME_INFO.

   This includes special registers such as pc and fp saved in special

   ways in the stack frame.  sp is even more special:

   the address we return for it IS the sp for the next frame.

   We cache the result of doing this in the frame_cache_obstack, since

   it is fairly expensive.  */

void

frame_find_saved_regs (fip, fsrp)

     struct frame_info *fip;

     struct frame_saved_regs *fsrp;

{

  int locals;

  CORE_ADDR pc;

  CORE_ADDR adr;

  int i;

  memset (fsrp, 0, sizeof *fsrp);

  pc = skip_adjust (get_pc_function_start (fip->pc), &locals);

  {

    adr = FRAME_FP (fip) - locals;

    for (i = 0; i < 8; i++)

      {

        int word = read_memory_short (pc);

        pc += 2;

        if (IS_PUSHL (word))

          {

            fsrp->regs[word & 0xf] = adr;

            fsrp->regs[(word & 0xf) + 1] = adr - 2;

            adr -= 4;

          }

        else if (IS_PUSHW (word))

          {

            fsrp->regs[word & 0xf] = adr;

            adr -= 2;

          }

        else

          break;

      }

  }

  fsrp->regs[PC_REGNUM] = fip->frame + 4;

  fsrp->regs[FP_REGNUM] = fip->frame;

}

#endif

int

z8k_saved_pc_after_call (struct frame_info *frame)

{

  return ADDR_BITS_REMOVE

    (read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));

}

void

extract_return_value (type, regbuf, valbuf)

     struct type *type;

     char *regbuf;

     char *valbuf;

{

  int b;

  int len = TYPE_LENGTH (type);

  for (b = 0; b < len; b += 2)

    {

      int todo = len - b;

      if (todo > 2)

        todo = 2;

      memcpy (valbuf + b, regbuf + b, todo);

    }

}

void

write_return_value (type, valbuf)

     struct type *type;

     char *valbuf;

{

  int reg;

  int len;

  for (len = 0; len < TYPE_LENGTH (type); len += 2)

    write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);

}

void

store_struct_return (addr, sp)

     CORE_ADDR addr;

     CORE_ADDR sp;

{

  write_register (2, addr);

}

void

z8k_print_register_hook (regno)

     int regno;

{

  if ((regno & 1) == 0 && regno < 16)

    {

      unsigned short l[2];

      read_relative_register_raw_bytes (regno, (char *) (l + 0));

      read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));

      printf_unfiltered ("\t");

      printf_unfiltered ("%04x%04x", l[0], l[1]);

    }

  if ((regno & 3) == 0 && regno < 16)

    {

      unsigned short l[4];

      read_relative_register_raw_bytes (regno, (char *) (l + 0));

      read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));

      read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));

      read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));

      printf_unfiltered ("\t");

      printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);

    }

  if (regno == 15)

    {

      unsigned short rval;

      int i;

      read_relative_register_raw_bytes (regno, (char *) (&rval));

      printf_unfiltered ("\n");

      for (i = 0; i < 10; i += 2)

        {

          printf_unfiltered ("(sp+%d=%04x)", i,

                             (unsigned int)read_memory_short (rval + i));

        }

    }

}

void

z8k_pop_frame ()

{

}

struct cmd_list_element *setmemorylist;

void

z8k_set_pointer_size (newsize)

     int newsize;

{

  static int oldsize = 0;

  if (oldsize != newsize)

    {

      printf_unfiltered ("pointer size set to %d bits\n", newsize);

      oldsize = newsize;

      if (newsize == 32)

        {

          BIG = 1;

        }

      else

        {

          BIG = 0;

        }

      /* FIXME: This code should be using the GDBARCH framework to

         handle changed type sizes.  If this problem is ever fixed

         (the direct reference to _initialize_gdbtypes() below

         eliminated) then Makefile.in should be updated so that

         z8k-tdep.c is again compiled with -Werror. */

      _initialize_gdbtypes ();

    }

}

static void

segmented_command (args, from_tty)

     char *args;

     int from_tty;

{

  z8k_set_pointer_size (32);

}

static void

unsegmented_command (args, from_tty)

     char *args;

     int from_tty;

{

  z8k_set_pointer_size (16);

}

static void

set_memory (args, from_tty)

     char *args;

     int from_tty;

{

  printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");

  help_list (setmemorylist, "set memory ", -1, gdb_stdout);

}

void

_initialize_z8ktdep ()

{

  tm_print_insn = gdb_print_insn_z8k;

  add_prefix_cmd ("memory", no_class, set_memory,

                  "set the memory model", &setmemorylist, "set memory ", 0,

                  &setlist);

  add_cmd ("segmented", class_support, segmented_command,

           "Set segmented memory model.", &setmemorylist);

  add_cmd ("unsegmented", class_support, unsegmented_command,

           "Set unsegmented memory model.", &setmemorylist);

}