Subversion Repositories openrisc_me

/* Target-dependent code for the Motorola 68000 series.

   Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1999, 2000, 2001,

   2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

   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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "dwarf2-frame.h"

#include "frame.h"

#include "frame-base.h"

#include "frame-unwind.h"

#include "gdbtypes.h"

#include "symtab.h"

#include "gdbcore.h"

#include "value.h"

#include "gdb_string.h"

#include "gdb_assert.h"

#include "inferior.h"

#include "regcache.h"

#include "arch-utils.h"

#include "osabi.h"

#include "dis-asm.h"

#include "target-descriptions.h"

#include "m68k-tdep.h"

#define P_LINKL_FP      0x480e

#define P_LINKW_FP      0x4e56

#define P_PEA_FP        0x4856

#define P_MOVEAL_SP_FP  0x2c4f

#define P_ADDAW_SP      0xdefc

#define P_ADDAL_SP      0xdffc

#define P_SUBQW_SP      0x514f

#define P_SUBQL_SP      0x518f

#define P_LEA_SP_SP     0x4fef

#define P_LEA_PC_A5     0x4bfb0170

#define P_FMOVEMX_SP    0xf227

#define P_MOVEL_SP      0x2f00

#define P_MOVEML_SP     0x48e7

/* Offset from SP to first arg on stack at first instruction of a function */

#define SP_ARG0 (1 * 4)

#if !defined (BPT_VECTOR)

#define BPT_VECTOR 0xf

#endif

static const gdb_byte *

m68k_local_breakpoint_from_pc (struct gdbarch *gdbarch,

                               CORE_ADDR *pcptr, int *lenptr)

{

  static gdb_byte break_insn[] = {0x4e, (0x40 | BPT_VECTOR)};

  *lenptr = sizeof (break_insn);

  return break_insn;

}

/* Construct types for ISA-specific registers.  */

static struct type *

m68k_ps_type (struct gdbarch *gdbarch)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  if (!tdep->m68k_ps_type)

    {

      struct type *type;

      type = arch_flags_type (gdbarch, "builtin_type_m68k_ps", 4);

      append_flags_type_flag (type, 0, "C");

      append_flags_type_flag (type, 1, "V");

      append_flags_type_flag (type, 2, "Z");

      append_flags_type_flag (type, 3, "N");

      append_flags_type_flag (type, 4, "X");

      append_flags_type_flag (type, 8, "I0");

      append_flags_type_flag (type, 9, "I1");

      append_flags_type_flag (type, 10, "I2");

      append_flags_type_flag (type, 12, "M");

      append_flags_type_flag (type, 13, "S");

      append_flags_type_flag (type, 14, "T0");

      append_flags_type_flag (type, 15, "T1");

      tdep->m68k_ps_type = type;

    }

  return tdep->m68k_ps_type;

}

static struct type *

m68881_ext_type (struct gdbarch *gdbarch)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  if (!tdep->m68881_ext_type)

    tdep->m68881_ext_type

      = arch_float_type (gdbarch, -1, "builtin_type_m68881_ext",

                         floatformats_m68881_ext);

  return tdep->m68881_ext_type;

}

/* Return the GDB type object for the "standard" data type of data in

   register N.  This should be int for D0-D7, SR, FPCONTROL and

   FPSTATUS, long double for FP0-FP7, and void pointer for all others

   (A0-A7, PC, FPIADDR).  Note, for registers which contain

   addresses return pointer to void, not pointer to char, because we

   don't want to attempt to print the string after printing the

   address.  */

static struct type *

m68k_register_type (struct gdbarch *gdbarch, int regnum)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  if (tdep->fpregs_present)

    {

      if (regnum >= gdbarch_fp0_regnum (gdbarch)

          && regnum <= gdbarch_fp0_regnum (gdbarch) + 7)

        {

          if (tdep->flavour == m68k_coldfire_flavour)

            return builtin_type (gdbarch)->builtin_double;

          else

            return m68881_ext_type (gdbarch);

        }

      if (regnum == M68K_FPI_REGNUM)

        return builtin_type (gdbarch)->builtin_func_ptr;

      if (regnum == M68K_FPC_REGNUM || regnum == M68K_FPS_REGNUM)

        return builtin_type (gdbarch)->builtin_int32;

    }

  else

    {

      if (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FPI_REGNUM)

        return builtin_type (gdbarch)->builtin_int0;

    }

  if (regnum == gdbarch_pc_regnum (gdbarch))

    return builtin_type (gdbarch)->builtin_func_ptr;

  if (regnum >= M68K_A0_REGNUM && regnum <= M68K_A0_REGNUM + 7)

    return builtin_type (gdbarch)->builtin_data_ptr;

  if (regnum == M68K_PS_REGNUM)

    return m68k_ps_type (gdbarch);

  return builtin_type (gdbarch)->builtin_int32;

}

static const char *m68k_register_names[] = {

    "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7",

    "a0", "a1", "a2", "a3", "a4", "a5", "fp", "sp",

    "ps", "pc",

    "fp0", "fp1", "fp2", "fp3", "fp4", "fp5", "fp6", "fp7",

    "fpcontrol", "fpstatus", "fpiaddr"

  };

/* Function: m68k_register_name

   Returns the name of the standard m68k register regnum. */

static const char *

m68k_register_name (struct gdbarch *gdbarch, int regnum)

{

  if (regnum < 0 || regnum >= ARRAY_SIZE (m68k_register_names))

    internal_error (__FILE__, __LINE__,

                    _("m68k_register_name: illegal register number %d"), regnum);

  else if (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FPI_REGNUM

           && gdbarch_tdep (gdbarch)->fpregs_present == 0)

    return "";

  else

    return m68k_register_names[regnum];

}

/* Return nonzero if a value of type TYPE stored in register REGNUM

   needs any special handling.  */

static int

m68k_convert_register_p (struct gdbarch *gdbarch, int regnum, struct type *type)

{

  if (!gdbarch_tdep (gdbarch)->fpregs_present)

    return 0;

  return (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FP0_REGNUM + 7

          && type != register_type (gdbarch, M68K_FP0_REGNUM));

}

/* Read a value of type TYPE from register REGNUM in frame FRAME, and

   return its contents in TO.  */

static void

m68k_register_to_value (struct frame_info *frame, int regnum,

                        struct type *type, gdb_byte *to)

{

  gdb_byte from[M68K_MAX_REGISTER_SIZE];

  struct type *fpreg_type = register_type (get_frame_arch (frame),

                                           M68K_FP0_REGNUM);

  /* We only support floating-point values.  */

  if (TYPE_CODE (type) != TYPE_CODE_FLT)

    {

      warning (_("Cannot convert floating-point register value "

               "to non-floating-point type."));

      return;

    }

  /* Convert to TYPE.  */

  get_frame_register (frame, regnum, from);

  convert_typed_floating (from, fpreg_type, to, type);

}

/* Write the contents FROM of a value of type TYPE into register

   REGNUM in frame FRAME.  */

static void

m68k_value_to_register (struct frame_info *frame, int regnum,

                        struct type *type, const gdb_byte *from)

{

  gdb_byte to[M68K_MAX_REGISTER_SIZE];

  struct type *fpreg_type = register_type (get_frame_arch (frame),

                                           M68K_FP0_REGNUM);

  /* We only support floating-point values.  */

  if (TYPE_CODE (type) != TYPE_CODE_FLT)

    {

      warning (_("Cannot convert non-floating-point type "

               "to floating-point register value."));

      return;

    }

  /* Convert from TYPE.  */

  convert_typed_floating (from, type, to, fpreg_type);

  put_frame_register (frame, regnum, to);

}

/* There is a fair number of calling conventions that are in somewhat

   wide use.  The 68000/08/10 don't support an FPU, not even as a

   coprocessor.  All function return values are stored in %d0/%d1.

   Structures are returned in a static buffer, a pointer to which is

   returned in %d0.  This means that functions returning a structure

   are not re-entrant.  To avoid this problem some systems use a

   convention where the caller passes a pointer to a buffer in %a1

   where the return values is to be stored.  This convention is the

   default, and is implemented in the function m68k_return_value.

   The 68020/030/040/060 do support an FPU, either as a coprocessor

   (68881/2) or built-in (68040/68060).  That's why System V release 4

   (SVR4) instroduces a new calling convention specified by the SVR4

   psABI.  Integer values are returned in %d0/%d1, pointer return

   values in %a0 and floating values in %fp0.  When calling functions

   returning a structure the caller should pass a pointer to a buffer

   for the return value in %a0.  This convention is implemented in the

   function m68k_svr4_return_value, and by appropriately setting the

   struct_value_regnum member of `struct gdbarch_tdep'.

   GNU/Linux returns values in the same way as SVR4 does, but uses %a1

   for passing the structure return value buffer.

   GCC can also generate code where small structures are returned in

   %d0/%d1 instead of in memory by using -freg-struct-return.  This is

   the default on NetBSD a.out, OpenBSD and GNU/Linux and several

   embedded systems.  This convention is implemented by setting the

   struct_return member of `struct gdbarch_tdep' to reg_struct_return.  */

/* Read a function return value of TYPE from REGCACHE, and copy that

   into VALBUF.  */

static void

m68k_extract_return_value (struct type *type, struct regcache *regcache,

                           gdb_byte *valbuf)

{

  int len = TYPE_LENGTH (type);

  gdb_byte buf[M68K_MAX_REGISTER_SIZE];

  if (len <= 4)

    {

      regcache_raw_read (regcache, M68K_D0_REGNUM, buf);

      memcpy (valbuf, buf + (4 - len), len);

    }

  else if (len <= 8)

    {

      regcache_raw_read (regcache, M68K_D0_REGNUM, buf);

      memcpy (valbuf, buf + (8 - len), len - 4);

      regcache_raw_read (regcache, M68K_D1_REGNUM, valbuf + (len - 4));

    }

  else

    internal_error (__FILE__, __LINE__,

                    _("Cannot extract return value of %d bytes long."), len);

}

static void

m68k_svr4_extract_return_value (struct type *type, struct regcache *regcache,

                                gdb_byte *valbuf)

{

  int len = TYPE_LENGTH (type);

  gdb_byte buf[M68K_MAX_REGISTER_SIZE];

  struct gdbarch *gdbarch = get_regcache_arch (regcache);

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  if (tdep->float_return && TYPE_CODE (type) == TYPE_CODE_FLT)

    {

      struct type *fpreg_type = register_type (gdbarch, M68K_FP0_REGNUM);

      regcache_raw_read (regcache, M68K_FP0_REGNUM, buf);

      convert_typed_floating (buf, fpreg_type, valbuf, type);

    }

  else if (TYPE_CODE (type) == TYPE_CODE_PTR && len == 4)

    regcache_raw_read (regcache, M68K_A0_REGNUM, valbuf);

  else

    m68k_extract_return_value (type, regcache, valbuf);

}

/* Write a function return value of TYPE from VALBUF into REGCACHE.  */

static void

m68k_store_return_value (struct type *type, struct regcache *regcache,

                         const gdb_byte *valbuf)

{

  int len = TYPE_LENGTH (type);

  if (len <= 4)

    regcache_raw_write_part (regcache, M68K_D0_REGNUM, 4 - len, len, valbuf);

  else if (len <= 8)

    {

      regcache_raw_write_part (regcache, M68K_D0_REGNUM, 8 - len,

                               len - 4, valbuf);

      regcache_raw_write (regcache, M68K_D1_REGNUM, valbuf + (len - 4));

    }

  else

    internal_error (__FILE__, __LINE__,

                    _("Cannot store return value of %d bytes long."), len);

}

static void

m68k_svr4_store_return_value (struct type *type, struct regcache *regcache,

                              const gdb_byte *valbuf)

{

  int len = TYPE_LENGTH (type);

  struct gdbarch *gdbarch = get_regcache_arch (regcache);

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  if (tdep->float_return && TYPE_CODE (type) == TYPE_CODE_FLT)

    {

      struct type *fpreg_type = register_type (gdbarch, M68K_FP0_REGNUM);

      gdb_byte buf[M68K_MAX_REGISTER_SIZE];

      convert_typed_floating (valbuf, type, buf, fpreg_type);

      regcache_raw_write (regcache, M68K_FP0_REGNUM, buf);

    }

  else if (TYPE_CODE (type) == TYPE_CODE_PTR && len == 4)

    {

      regcache_raw_write (regcache, M68K_A0_REGNUM, valbuf);

      regcache_raw_write (regcache, M68K_D0_REGNUM, valbuf);

    }

  else

    m68k_store_return_value (type, regcache, valbuf);

}

/* Return non-zero if TYPE, which is assumed to be a structure or

   union type, should be returned in registers for architecture

   GDBARCH.  */

static int

m68k_reg_struct_return_p (struct gdbarch *gdbarch, struct type *type)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  enum type_code code = TYPE_CODE (type);

  int len = TYPE_LENGTH (type);

  gdb_assert (code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION);

  if (tdep->struct_return == pcc_struct_return)

    return 0;

  return (len == 1 || len == 2 || len == 4 || len == 8);

}

/* Determine, for architecture GDBARCH, how a return value of TYPE

   should be returned.  If it is supposed to be returned in registers,

   and READBUF is non-zero, read the appropriate value from REGCACHE,

   and copy it into READBUF.  If WRITEBUF is non-zero, write the value

   from WRITEBUF into REGCACHE.  */

static enum return_value_convention

m68k_return_value (struct gdbarch *gdbarch, struct type *func_type,

                   struct type *type, struct regcache *regcache,

                   gdb_byte *readbuf, const gdb_byte *writebuf)

{

  enum type_code code = TYPE_CODE (type);

  /* GCC returns a `long double' in memory too.  */

  if (((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION)

       && !m68k_reg_struct_return_p (gdbarch, type))

      || (code == TYPE_CODE_FLT && TYPE_LENGTH (type) == 12))

    {

      /* The default on m68k is to return structures in static memory.

         Consequently a function must return the address where we can

         find the return value.  */

      if (readbuf)

        {

          ULONGEST addr;

          regcache_raw_read_unsigned (regcache, M68K_D0_REGNUM, &addr);

          read_memory (addr, readbuf, TYPE_LENGTH (type));

        }

      return RETURN_VALUE_ABI_RETURNS_ADDRESS;

    }

  if (readbuf)

    m68k_extract_return_value (type, regcache, readbuf);

  if (writebuf)

    m68k_store_return_value (type, regcache, writebuf);

  return RETURN_VALUE_REGISTER_CONVENTION;

}

static enum return_value_convention

m68k_svr4_return_value (struct gdbarch *gdbarch, struct type *func_type,

                        struct type *type, struct regcache *regcache,

                        gdb_byte *readbuf, const gdb_byte *writebuf)

{

  enum type_code code = TYPE_CODE (type);

  if ((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION)

      && !m68k_reg_struct_return_p (gdbarch, type))

    {

      /* The System V ABI says that:

         "A function returning a structure or union also sets %a0 to

         the value it finds in %a0.  Thus when the caller receives

         control again, the address of the returned object resides in

         register %a0."

         So the ABI guarantees that we can always find the return

         value just after the function has returned.  */

      if (readbuf)

        {

          ULONGEST addr;

          regcache_raw_read_unsigned (regcache, M68K_A0_REGNUM, &addr);

          read_memory (addr, readbuf, TYPE_LENGTH (type));

        }

      return RETURN_VALUE_ABI_RETURNS_ADDRESS;

    }

  /* This special case is for structures consisting of a single

     `float' or `double' member.  These structures are returned in

     %fp0.  For these structures, we call ourselves recursively,

     changing TYPE into the type of the first member of the structure.

     Since that should work for all structures that have only one

     member, we don't bother to check the member's type here.  */

  if (code == TYPE_CODE_STRUCT && TYPE_NFIELDS (type) == 1)

    {

      type = check_typedef (TYPE_FIELD_TYPE (type, 0));

      return m68k_svr4_return_value (gdbarch, func_type, type, regcache,

                                     readbuf, writebuf);

    }

  if (readbuf)

    m68k_svr4_extract_return_value (type, regcache, readbuf);

  if (writebuf)

    m68k_svr4_store_return_value (type, regcache, writebuf);

  return RETURN_VALUE_REGISTER_CONVENTION;

}

/* Always align the frame to a 4-byte boundary.  This is required on

   coldfire and harmless on the rest.  */

static CORE_ADDR

m68k_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)

{

  /* Align the stack to four bytes.  */

  return sp & ~3;

}

static CORE_ADDR

m68k_push_dummy_call (struct gdbarch *gdbarch, struct value *function,

                      struct regcache *regcache, CORE_ADDR bp_addr, int nargs,

                      struct value **args, CORE_ADDR sp, int struct_return,

                      CORE_ADDR struct_addr)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  gdb_byte buf[4];

  int i;

  /* Push arguments in reverse order.  */

  for (i = nargs - 1; i >= 0; i--)

    {

      struct type *value_type = value_enclosing_type (args[i]);

      int len = TYPE_LENGTH (value_type);

      int container_len = (len + 3) & ~3;

      int offset;

      /* Non-scalars bigger than 4 bytes are left aligned, others are

         right aligned.  */

      if ((TYPE_CODE (value_type) == TYPE_CODE_STRUCT

           || TYPE_CODE (value_type) == TYPE_CODE_UNION

           || TYPE_CODE (value_type) == TYPE_CODE_ARRAY)

          && len > 4)

        offset = 0;

      else

        offset = container_len - len;

      sp -= container_len;

      write_memory (sp + offset, value_contents_all (args[i]), len);

    }

  /* Store struct value address.  */

  if (struct_return)

    {

      store_unsigned_integer (buf, 4, byte_order, struct_addr);

      regcache_cooked_write (regcache, tdep->struct_value_regnum, buf);

    }

  /* Store return address.  */

  sp -= 4;

  store_unsigned_integer (buf, 4, byte_order, bp_addr);

  write_memory (sp, buf, 4);

  /* Finally, update the stack pointer...  */

  store_unsigned_integer (buf, 4, byte_order, sp);

  regcache_cooked_write (regcache, M68K_SP_REGNUM, buf);

  /* ...and fake a frame pointer.  */

  regcache_cooked_write (regcache, M68K_FP_REGNUM, buf);

  /* DWARF2/GCC uses the stack address *before* the function call as a

     frame's CFA.  */

  return sp + 8;

}

/* Convert a dwarf or dwarf2 regnumber to a GDB regnum.  */

static int

m68k_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int num)

{

  if (num < 8)

    /* d0..7 */

    return (num - 0) + M68K_D0_REGNUM;

  else if (num < 16)

    /* a0..7 */

    return (num - 8) + M68K_A0_REGNUM;

  else if (num < 24 && gdbarch_tdep (gdbarch)->fpregs_present)

    /* fp0..7 */

    return (num - 16) + M68K_FP0_REGNUM;

  else if (num == 25)

    /* pc */

    return M68K_PC_REGNUM;

  else

    return gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);

}

struct m68k_frame_cache

{

  /* Base address.  */

  CORE_ADDR base;

  CORE_ADDR sp_offset;

  CORE_ADDR pc;

  /* Saved registers.  */

  CORE_ADDR saved_regs[M68K_NUM_REGS];

  CORE_ADDR saved_sp;

  /* Stack space reserved for local variables.  */

  long locals;

};

/* Allocate and initialize a frame cache.  */

static struct m68k_frame_cache *

m68k_alloc_frame_cache (void)

{

  struct m68k_frame_cache *cache;

  int i;

  cache = FRAME_OBSTACK_ZALLOC (struct m68k_frame_cache);

  /* Base address.  */

  cache->base = 0;

  cache->sp_offset = -4;

  cache->pc = 0;

  /* Saved registers.  We initialize these to -1 since zero is a valid

     offset (that's where %fp is supposed to be stored).  */

  for (i = 0; i < M68K_NUM_REGS; i++)

    cache->saved_regs[i] = -1;

  /* Frameless until proven otherwise.  */

  cache->locals = -1;

  return cache;

}

/* Check whether PC points at a code that sets up a new stack frame.

   If so, it updates CACHE and returns the address of the first

   instruction after the sequence that sets removes the "hidden"

   argument from the stack or CURRENT_PC, whichever is smaller.

   Otherwise, return PC.  */

static CORE_ADDR

m68k_analyze_frame_setup (struct gdbarch *gdbarch,

                          CORE_ADDR pc, CORE_ADDR current_pc,

                          struct m68k_frame_cache *cache)

{

  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  int op;

  if (pc >= current_pc)

    return current_pc;

  op = read_memory_unsigned_integer (pc, 2, byte_order);

  if (op == P_LINKW_FP || op == P_LINKL_FP || op == P_PEA_FP)

    {

      cache->saved_regs[M68K_FP_REGNUM] = 0;

      cache->sp_offset += 4;

      if (op == P_LINKW_FP)

        {

          /* link.w %fp, #-N */

          /* link.w %fp, #0; adda.l #-N, %sp */

          cache->locals = -read_memory_integer (pc + 2, 2, byte_order);

          if (pc + 4 < current_pc && cache->locals == 0)

            {

              op = read_memory_unsigned_integer (pc + 4, 2, byte_order);

              if (op == P_ADDAL_SP)

                {

                  cache->locals = read_memory_integer (pc + 6, 4, byte_order);

                  return pc + 10;

                }

            }

          return pc + 4;

        }

      else if (op == P_LINKL_FP)

        {

          /* link.l %fp, #-N */

          cache->locals = -read_memory_integer (pc + 2, 4, byte_order);

          return pc + 6;

        }

      else

        {

          /* pea (%fp); movea.l %sp, %fp */

          cache->locals = 0;

          if (pc + 2 < current_pc)

            {

              op = read_memory_unsigned_integer (pc + 2, 2, byte_order);

              if (op == P_MOVEAL_SP_FP)

                {

                  /* move.l %sp, %fp */

                  return pc + 4;

                }

            }

          return pc + 2;

        }

    }

  else if ((op & 0170777) == P_SUBQW_SP || (op & 0170777) == P_SUBQL_SP)

    {

      /* subq.[wl] #N,%sp */

      /* subq.[wl] #8,%sp; subq.[wl] #N,%sp */

      cache->locals = (op & 07000) == 0 ? 8 : (op & 07000) >> 9;

      if (pc + 2 < current_pc)