aboutsummaryrefslogtreecommitdiff
path: root/opcodes/cgen-dis.c
blob: 186863456710200453fef1a5319e382132e95d86 (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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
/* CGEN generic disassembler support code.
   Copyright (C) 1996-2019 Free Software Foundation, Inc.

   This file is part of libopcodes.

   This library 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, or (at your option)
   any later version.

   It 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 <stdio.h>
#include "ansidecl.h"
#include "libiberty.h"
#include "bfd.h"
#include "symcat.h"
#include "opcode/cgen.h"

static CGEN_INSN_LIST *  hash_insn_array        (CGEN_CPU_DESC, const CGEN_INSN *, int, int, CGEN_INSN_LIST **, CGEN_INSN_LIST *);
static CGEN_INSN_LIST *  hash_insn_list         (CGEN_CPU_DESC, const CGEN_INSN_LIST *, CGEN_INSN_LIST **, CGEN_INSN_LIST *);
static void              build_dis_hash_table   (CGEN_CPU_DESC);
static int		 count_decodable_bits   (const CGEN_INSN *);
static void		 add_insn_to_hash_chain (CGEN_INSN_LIST *,
						 const CGEN_INSN *,
						 CGEN_INSN_LIST **,
						 unsigned int);

/* Return the number of decodable bits in this insn.  */
static int
count_decodable_bits (const CGEN_INSN *insn)
{
  unsigned mask = CGEN_INSN_BASE_MASK (insn);
  int bits = 0;
  unsigned m;

  for (m = 1; m != 0; m <<= 1)
    {
      if (mask & m)
	++bits;
    }
  return bits;
}

/* Add an instruction to the hash chain.  */
static void
add_insn_to_hash_chain (CGEN_INSN_LIST *hentbuf,
			const CGEN_INSN *insn,
			CGEN_INSN_LIST **htable,
			unsigned int hash)
{
  CGEN_INSN_LIST *current_buf;
  CGEN_INSN_LIST *previous_buf;
  int insn_decodable_bits;

  /* Add insns sorted by the number of decodable bits, in decreasing order.
     This ensures that any insn which is a special case of another will be
     checked first.  */
  insn_decodable_bits = count_decodable_bits (insn);
  previous_buf = NULL;
  for (current_buf = htable[hash]; current_buf != NULL;
       current_buf = current_buf->next)
    {
      int current_decodable_bits = count_decodable_bits (current_buf->insn);
      if (insn_decodable_bits >= current_decodable_bits)
	break;
      previous_buf = current_buf;
    }

  /* Now insert the new insn.  */
  hentbuf->insn = insn;
  hentbuf->next = current_buf;
  if (previous_buf == NULL)
    htable[hash] = hentbuf;
  else
    previous_buf->next = hentbuf;
}

/* Subroutine of build_dis_hash_table to add INSNS to the hash table.

   COUNT is the number of elements in INSNS.
   ENTSIZE is sizeof (CGEN_IBASE) for the target.
   ??? No longer used but leave in for now.
   HTABLE points to the hash table.
   HENTBUF is a pointer to sufficiently large buffer of hash entries.
   The result is a pointer to the next entry to use.

   The table is scanned backwards as additions are made to the front of the
   list and we want earlier ones to be prefered.  */

static CGEN_INSN_LIST *
hash_insn_array (CGEN_CPU_DESC cd,
		 const CGEN_INSN * insns,
		 int count,
		 int entsize ATTRIBUTE_UNUSED,
		 CGEN_INSN_LIST ** htable,
		 CGEN_INSN_LIST * hentbuf)
{
  int big_p = CGEN_CPU_INSN_ENDIAN (cd) == CGEN_ENDIAN_BIG;
  int i;

  for (i = count - 1; i >= 0; --i, ++hentbuf)
    {
      unsigned int hash;
      char buf [4];
      unsigned long value;
      const CGEN_INSN *insn = &insns[i];

      if (! (* cd->dis_hash_p) (insn))
	continue;

      /* We don't know whether the target uses the buffer or the base insn
	 to hash on, so set both up.  */

      value = CGEN_INSN_BASE_VALUE (insn);
      bfd_put_bits ((bfd_vma) value,
		    buf,
		    CGEN_INSN_MASK_BITSIZE (insn),
		    big_p);
      hash = (* cd->dis_hash) (buf, value);
      add_insn_to_hash_chain (hentbuf, insn, htable, hash);
    }

  return hentbuf;
}

/* Subroutine of build_dis_hash_table to add INSNS to the hash table.
   This function is identical to hash_insn_array except the insns are
   in a list.  */

static CGEN_INSN_LIST *
hash_insn_list (CGEN_CPU_DESC cd,
		const CGEN_INSN_LIST *insns,
		CGEN_INSN_LIST **htable,
		CGEN_INSN_LIST *hentbuf)
{
  int big_p = CGEN_CPU_INSN_ENDIAN (cd) == CGEN_ENDIAN_BIG;
  const CGEN_INSN_LIST *ilist;

  for (ilist = insns; ilist != NULL; ilist = ilist->next, ++ hentbuf)
    {
      unsigned int hash;
      char buf[4];
      unsigned long value;

      if (! (* cd->dis_hash_p) (ilist->insn))
	continue;

      /* We don't know whether the target uses the buffer or the base insn
	 to hash on, so set both up.  */

      value = CGEN_INSN_BASE_VALUE (ilist->insn);
      bfd_put_bits((bfd_vma) value,
		   buf,
		   CGEN_INSN_MASK_BITSIZE (ilist->insn),
		   big_p);
      hash = (* cd->dis_hash) (buf, value);
      add_insn_to_hash_chain (hentbuf, ilist->insn, htable, hash);
    }

  return hentbuf;
}

/* Build the disassembler instruction hash table.  */

static void
build_dis_hash_table (CGEN_CPU_DESC cd)
{
  int count = cgen_insn_count (cd) + cgen_macro_insn_count (cd);
  CGEN_INSN_TABLE *insn_table = & cd->insn_table;
  CGEN_INSN_TABLE *macro_insn_table = & cd->macro_insn_table;
  unsigned int hash_size = cd->dis_hash_size;
  CGEN_INSN_LIST *hash_entry_buf;
  CGEN_INSN_LIST **dis_hash_table;
  CGEN_INSN_LIST *dis_hash_table_entries;

  /* The space allocated for the hash table consists of two parts:
     the hash table and the hash lists.  */

  dis_hash_table = (CGEN_INSN_LIST **)
    xmalloc (hash_size * sizeof (CGEN_INSN_LIST *));
  memset (dis_hash_table, 0, hash_size * sizeof (CGEN_INSN_LIST *));
  dis_hash_table_entries = hash_entry_buf = (CGEN_INSN_LIST *)
    xmalloc (count * sizeof (CGEN_INSN_LIST));

  /* Add compiled in insns.
     Don't include the first one as it is a reserved entry.  */
  /* ??? It was the end of all hash chains, and also the special
     "invalid insn" marker.  May be able to do it differently now.  */

  hash_entry_buf = hash_insn_array (cd,
				    insn_table->init_entries + 1,
				    insn_table->num_init_entries - 1,
				    insn_table->entry_size,
				    dis_hash_table, hash_entry_buf);

  /* Add compiled in macro-insns.  */

  hash_entry_buf = hash_insn_array (cd, macro_insn_table->init_entries,
				    macro_insn_table->num_init_entries,
				    macro_insn_table->entry_size,
				    dis_hash_table, hash_entry_buf);

  /* Add runtime added insns.
     Later added insns will be prefered over earlier ones.  */

  hash_entry_buf = hash_insn_list (cd, insn_table->new_entries,
				   dis_hash_table, hash_entry_buf);

  /* Add runtime added macro-insns.  */

  hash_insn_list (cd, macro_insn_table->new_entries,
		  dis_hash_table, hash_entry_buf);

  cd->dis_hash_table = dis_hash_table;
  cd->dis_hash_table_entries = dis_hash_table_entries;
}

/* Return the first entry in the hash list for INSN.  */

CGEN_INSN_LIST *
cgen_dis_lookup_insn (CGEN_CPU_DESC cd, const char * buf, CGEN_INSN_INT value)
{
  unsigned int hash;

  if (cd->dis_hash_table == NULL)
    build_dis_hash_table (cd);

  hash = (* cd->dis_hash) (buf, value);

  return cd->dis_hash_table[hash];
}