1/* BFD support for the Intel 386 architecture.
2   Copyright (C) 1992-2022 Free Software Foundation, Inc.
3
4   This file is part of BFD, the Binary File Descriptor library.
5
6   This program is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 3 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program; if not, write to the Free Software
18   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
19   MA 02110-1301, USA.  */
20
21#include "sysdep.h"
22#include "bfd.h"
23#include "libbfd.h"
24#include "libiberty.h"
25
26extern void * bfd_arch_i386_short_nop_fill (bfd_size_type, bool,
27					    bool);
28
29static const bfd_arch_info_type *
30bfd_i386_compatible (const bfd_arch_info_type *a,
31		     const bfd_arch_info_type *b)
32{
33  const bfd_arch_info_type *compat = bfd_default_compatible (a, b);
34
35  /* Don't allow mixing x64_32 with x86_64.  */
36  if (compat
37      && (a->mach & bfd_mach_x64_32) != (b->mach & bfd_mach_x64_32))
38    compat = NULL;
39
40  return compat;
41}
42
43/* Fill the buffer with zero or nop instruction if CODE is TRUE.  Use
44   multi byte nop instructions if LONG_NOP is TRUE.  */
45
46static void *
47bfd_arch_i386_fill (bfd_size_type count, bool code,
48		    bool long_nop)
49{
50  /* nop */
51  static const char nop_1[] = { 0x90 };
52  /* xchg %ax,%ax */
53  static const char nop_2[] = { 0x66, 0x90 };
54  /* nopl (%[re]ax) */
55  static const char nop_3[] = { 0x0f, 0x1f, 0x00 };
56  /* nopl 0(%[re]ax) */
57  static const char nop_4[] = { 0x0f, 0x1f, 0x40, 0x00 };
58  /* nopl 0(%[re]ax,%[re]ax,1) */
59  static const char nop_5[] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
60  /* nopw 0(%[re]ax,%[re]ax,1) */
61  static const char nop_6[] = { 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00 };
62  /* nopl 0L(%[re]ax) */
63  static const char nop_7[] = { 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00 };
64  /* nopl 0L(%[re]ax,%[re]ax,1) */
65  static const char nop_8[] =
66    { 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00};
67  /* nopw 0L(%[re]ax,%[re]ax,1) */
68  static const char nop_9[] =
69    { 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 };
70  /* nopw %cs:0L(%[re]ax,%[re]ax,1) */
71  static const char nop_10[] =
72    { 0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 };
73  static const char *const nops[] =
74    { nop_1, nop_2, nop_3, nop_4, nop_5,
75      nop_6, nop_7, nop_8, nop_9, nop_10 };
76  bfd_size_type nop_size = long_nop ? ARRAY_SIZE (nops) : 2;
77
78  void *fill = bfd_malloc (count);
79  if (fill == NULL)
80    return fill;
81
82  if (code)
83    {
84      bfd_byte *p = fill;
85      while (count >= nop_size)
86	{
87	  memcpy (p, nops[nop_size - 1], nop_size);
88	  p += nop_size;
89	  count -= nop_size;
90	}
91      if (count != 0)
92	memcpy (p, nops[count - 1], count);
93    }
94  else
95    memset (fill, 0, count);
96
97  return fill;
98}
99
100/* Fill the buffer with zero or short nop instruction if CODE is true.  */
101
102void *
103bfd_arch_i386_short_nop_fill (bfd_size_type count,
104			      bool is_bigendian ATTRIBUTE_UNUSED,
105			      bool code)
106{
107  return bfd_arch_i386_fill (count, code, false);
108}
109
110/* Fill the buffer with zero or long nop instruction if CODE is TRUE.  */
111
112static void *
113bfd_arch_i386_long_nop_fill (bfd_size_type count,
114			     bool is_bigendian ATTRIBUTE_UNUSED,
115			     bool code)
116{
117  return bfd_arch_i386_fill (count, code, true);
118}
119
120#define N(BITS, MACH, NAME, PRINT, DEF, FILL, NEXT)	\
121  { BITS, /* Bits in a word.  */		\
122    BITS, /* Bits in an address.  */		\
123    8,    /* Bits in a byte. */			\
124    bfd_arch_i386,				\
125    MACH, /* Machine number.  */		\
126    NAME,					\
127    PRINT,					\
128    3,   /* Section alignment power.  */	\
129    DEF, /* Default architecture version ?  */	\
130    bfd_i386_compatible,			\
131    bfd_default_scan,				\
132    FILL,					\
133    NEXT,					\
134    0 /* Maximum instruction length.  */	\
135  }
136
137
138static const bfd_arch_info_type bfd_x64_32_arch_intel_syntax =
139  N (64, bfd_mach_x64_32_intel_syntax, "i386:intel", "i386:x64-32:intel",
140     false, bfd_arch_i386_long_nop_fill, NULL);
141
142static const bfd_arch_info_type bfd_x86_64_arch_intel_syntax =
143  N (64, bfd_mach_x86_64_intel_syntax, "i386:intel", "i386:x86-64:intel",
144     false, bfd_arch_i386_long_nop_fill, &bfd_x64_32_arch_intel_syntax);
145
146static const bfd_arch_info_type bfd_i386_arch_intel_syntax =
147  N (32, bfd_mach_i386_i386_intel_syntax, "i386:intel", "i386:intel",
148     true, bfd_arch_i386_short_nop_fill, &bfd_x86_64_arch_intel_syntax);
149
150
151static const bfd_arch_info_type i8086_arch =
152  N (32, bfd_mach_i386_i8086, "i8086", "i8086",
153     false, bfd_arch_i386_short_nop_fill, &bfd_i386_arch_intel_syntax);
154
155static const bfd_arch_info_type bfd_x64_32_arch =
156  N (64, bfd_mach_x64_32, "i386", "i386:x64-32",
157     false, bfd_arch_i386_long_nop_fill, &i8086_arch);
158
159static const bfd_arch_info_type bfd_x86_64_arch =
160  N (64, bfd_mach_x86_64, "i386", "i386:x86-64",
161     false, bfd_arch_i386_long_nop_fill, &bfd_x64_32_arch);
162
163const bfd_arch_info_type bfd_i386_arch =
164  N (32, bfd_mach_i386_i386, "i386", "i386",
165     true, bfd_arch_i386_short_nop_fill, &bfd_x86_64_arch);
166