aboutsummaryrefslogtreecommitdiff
path: root/bfd/cpu-i386.c
blob: e8880ee064af39c187ebe0aa3486c1fb77b6c707 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
/* BFD support for the Intel 386 architecture.
   Copyright (C) 1992-2022 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, bool,
					    bool);

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, bool code,
		    bool 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,
			      bool is_bigendian ATTRIBUTE_UNUSED,
			      bool 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,
			     bool is_bigendian ATTRIBUTE_UNUSED,
			     bool code)
{
  return bfd_arch_i386_fill (count, code, true);
}

#define N(BITS, MACH, NAME, PRINT, DEF, FILL, NEXT)	\
  { BITS, /* Bits in a word.  */		\
    BITS, /* Bits in an address.  */		\
    8,    /* Bits in a byte. */			\
    bfd_arch_i386,				\
    MACH, /* Machine number.  */		\
    NAME,					\
    PRINT,					\
    3,   /* Section alignment power.  */	\
    DEF, /* Default architecture version ?  */	\
    bfd_i386_compatible,			\
    bfd_default_scan,				\
    FILL,					\
    NEXT,					\
    0 /* Maximum instruction length.  */	\
  }


static const bfd_arch_info_type bfd_x64_32_arch_intel_syntax =
  N (64, bfd_mach_x64_32_intel_syntax, "i386:intel", "i386:x64-32:intel",
     false, bfd_arch_i386_long_nop_fill, NULL);

static const bfd_arch_info_type bfd_x86_64_arch_intel_syntax =
  N (64, bfd_mach_x86_64_intel_syntax, "i386:intel", "i386:x86-64:intel",
     false, bfd_arch_i386_long_nop_fill, &bfd_x64_32_arch_intel_syntax);

static const bfd_arch_info_type bfd_i386_arch_intel_syntax =
  N (32, bfd_mach_i386_i386_intel_syntax, "i386:intel", "i386:intel",
     true, bfd_arch_i386_short_nop_fill, &bfd_x86_64_arch_intel_syntax);


static const bfd_arch_info_type i8086_arch =
  N (32, bfd_mach_i386_i8086, "i8086", "i8086",
     false, bfd_arch_i386_short_nop_fill, &bfd_i386_arch_intel_syntax);

static const bfd_arch_info_type bfd_x64_32_arch =
  N (64, bfd_mach_x64_32, "i386", "i386:x64-32",
     false, bfd_arch_i386_long_nop_fill, &i8086_arch);

static const bfd_arch_info_type bfd_x86_64_arch =
  N (64, bfd_mach_x86_64, "i386", "i386:x86-64",
     false, bfd_arch_i386_long_nop_fill, &bfd_x64_32_arch);

const bfd_arch_info_type bfd_i386_arch =
  N (32, bfd_mach_i386_i386, "i386", "i386",
     true, bfd_arch_i386_short_nop_fill, &bfd_x86_64_arch);