Add new target_read_raw_memory function, and consolidate comments.

[deliverable/binutils-gdb.git] / bfd / cpu-i386.c

/* BFD support for the Intel 386 architecture.
   Copyright 1992, 1994, 1995, 1996, 1998, 2000, 2001, 2002, 2004, 2005,
   2007, 2009, 2010, 2011, 2013
   Free Software Foundation, Inc.

   This file is part of BFD, the Binary File Descriptor library.

   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, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
#include "libiberty.h"

extern void * bfd_arch_i386_short_nop_fill (bfd_size_type, bfd_boolean,
					    bfd_boolean);

static const bfd_arch_info_type *
bfd_i386_compatible (const bfd_arch_info_type *a,
		     const bfd_arch_info_type *b)
{
  const bfd_arch_info_type *compat = bfd_default_compatible (a, b);

  /* Don't allow mixing x64_32 with x86_64.  */
  if (compat
      && (a->mach & bfd_mach_x64_32) != (b->mach & bfd_mach_x64_32))
    compat = NULL;

  return compat;
}

/* Fill the buffer with zero or nop instruction if CODE is TRUE.  Use
   multi byte nop instructions if LONG_NOP is TRUE.  */

static void *
bfd_arch_i386_fill (bfd_size_type count, bfd_boolean code,
		    bfd_boolean long_nop)
{
  /* nop */
  static const char nop_1[] = { 0x90 };
  /* xchg %ax,%ax */
  static const char nop_2[] = { 0x66, 0x90 };
  /* nopl (%[re]ax) */
  static const char nop_3[] = { 0x0f, 0x1f, 0x00 };
  /* nopl 0(%[re]ax) */
  static const char nop_4[] = { 0x0f, 0x1f, 0x40, 0x00 };
  /* nopl 0(%[re]ax,%[re]ax,1) */
  static const char nop_5[] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
  /* nopw 0(%[re]ax,%[re]ax,1) */
  static const char nop_6[] = { 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00 };
  /* nopl 0L(%[re]ax) */
  static const char nop_7[] = { 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00 };
  /* nopl 0L(%[re]ax,%[re]ax,1) */
  static const char nop_8[] =
    { 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00};
  /* nopw 0L(%[re]ax,%[re]ax,1) */
  static const char nop_9[] =
    { 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 };
  /* nopw %cs:0L(%[re]ax,%[re]ax,1) */
  static const char nop_10[] =
    { 0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 };
  static const char *const nops[] =
    { nop_1, nop_2, nop_3, nop_4, nop_5,
      nop_6, nop_7, nop_8, nop_9, nop_10 };
  bfd_size_type nop_size = long_nop ? ARRAY_SIZE (nops) : 2;

  void *fill = bfd_malloc (count);
  if (fill == NULL)
    return fill;

  if (code)
    {
      bfd_byte *p = fill;
      while (count >= nop_size)
	{
	  memcpy (p, nops[nop_size - 1], nop_size);
	  p += nop_size;
	  count -= nop_size;
	}
      if (count != 0)
	memcpy (p, nops[count - 1], count);
    }
  else
    memset (fill, 0, count);

  return fill;
}

/* Fill the buffer with zero or short nop instruction if CODE is TRUE.  */

void *
bfd_arch_i386_short_nop_fill (bfd_size_type count,
			      bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
			      bfd_boolean code)
{
  return bfd_arch_i386_fill (count, code, FALSE);
}

/* Fill the buffer with zero or long nop instruction if CODE is TRUE.  */

static void *
bfd_arch_i386_long_nop_fill (bfd_size_type count,
			     bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
			     bfd_boolean code)
{
  return bfd_arch_i386_fill (count, code, TRUE);
}

/* Fill the buffer with zero, or one-byte nop instructions if CODE is TRUE.  */

static void *
bfd_arch_i386_onebyte_nop_fill (bfd_size_type count,
				bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
				bfd_boolean code)
{
  void *fill = bfd_malloc (count);
  if (fill != NULL)
    memset (fill, code ? 0x90 : 0, count);
  return fill;
}


static const bfd_arch_info_type bfd_x64_32_nacl_arch =
{
  64, /* 64 bits in a word */
  64, /* 64 bits in an address */
  8,  /* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_x64_32_nacl,
  "i386",
  "i386:x64-32:nacl",
  3,
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_onebyte_nop_fill,
  NULL
};

static const bfd_arch_info_type bfd_x86_64_nacl_arch =
{
  64, /* 64 bits in a word */
  64, /* 64 bits in an address */
  8,  /* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_x86_64_nacl,
  "i386",
  "i386:x86-64:nacl",
  3,
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_onebyte_nop_fill,
  &bfd_x64_32_nacl_arch
};

const bfd_arch_info_type bfd_i386_nacl_arch =
{
  32,	/* 32 bits in a word */
  32,	/* 32 bits in an address */
  8,	/* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_i386_i386_nacl,
  "i386",
  "i386:nacl",
  3,
  TRUE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_onebyte_nop_fill,
  &bfd_x86_64_nacl_arch
};

static const bfd_arch_info_type bfd_x64_32_arch_intel_syntax =
{
  64, /* 64 bits in a word */
  64, /* 64 bits in an address */
  8,  /* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_x64_32_intel_syntax,
  "i386:intel",
  "i386:x64-32:intel",
  3,
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_long_nop_fill,
  &bfd_i386_nacl_arch
};

static const bfd_arch_info_type bfd_x86_64_arch_intel_syntax =
{
  64, /* 64 bits in a word */
  64, /* 64 bits in an address */
  8,  /* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_x86_64_intel_syntax,
  "i386:intel",
  "i386:x86-64:intel",
  3,
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_long_nop_fill,
  &bfd_x64_32_arch_intel_syntax,
};

static const bfd_arch_info_type bfd_i386_arch_intel_syntax =
{
  32,	/* 32 bits in a word */
  32,	/* 32 bits in an address */
  8,	/* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_i386_i386_intel_syntax,
  "i386:intel",
  "i386:intel",
  3,
  TRUE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_short_nop_fill,
  &bfd_x86_64_arch_intel_syntax
};

static const bfd_arch_info_type i8086_arch =
{
  32,	/* 32 bits in a word */
  32,	/* 32 bits in an address (well, not really) */
  8,	/* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_i386_i8086,
  "i8086",
  "i8086",
  3,
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_short_nop_fill,
  &bfd_i386_arch_intel_syntax
};

static const bfd_arch_info_type bfd_x64_32_arch =
{
  64, /* 64 bits in a word */
  64, /* 64 bits in an address */
  8,  /* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_x64_32,
  "i386",
  "i386:x64-32",
  3,
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_long_nop_fill,
  &i8086_arch
};

static const bfd_arch_info_type bfd_x86_64_arch =
{
  64, /* 64 bits in a word */
  64, /* 64 bits in an address */
  8,  /* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_x86_64,
  "i386",
  "i386:x86-64",
  3,
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_long_nop_fill,
  &bfd_x64_32_arch
};

const bfd_arch_info_type bfd_i386_arch =
{
  32,	/* 32 bits in a word */
  32,	/* 32 bits in an address */
  8,	/* 8 bits in a byte */
  bfd_arch_i386,
  bfd_mach_i386_i386,
  "i386",
  "i386",
  3,
  TRUE,
  bfd_i386_compatible,
  bfd_default_scan,
  bfd_arch_i386_short_nop_fill,
  &bfd_x86_64_arch
};