opcodes/cgen-dis.c

   1 /* CGEN generic disassembler support code.
   2
   3    Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002
   4    Free Software Foundation, Inc.
   5
   6    This file is part of the GNU Binutils and GDB, the GNU debugger.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License along
  19    with this program; if not, write to the Free Software Foundation, Inc.,
  20    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 #include "sysdep.h"
  23 #include <stdio.h>
  24 #include "ansidecl.h"
  25 #include "libiberty.h"
  26 #include "bfd.h"
  27 #include "symcat.h"
  28 #include "opcode/cgen.h"
  29
  30 static CGEN_INSN_LIST *  hash_insn_array      PARAMS ((CGEN_CPU_DESC, const CGEN_INSN *, int, int, CGEN_INSN_LIST **, CGEN_INSN_LIST *));
  31 static CGEN_INSN_LIST *  hash_insn_list       PARAMS ((CGEN_CPU_DESC, const CGEN_INSN_LIST *, CGEN_INSN_LIST **, CGEN_INSN_LIST *));
  32 static void              build_dis_hash_table PARAMS ((CGEN_CPU_DESC));
  33 static int               count_decodable_bits PARAMS ((const CGEN_INSN *));
  34 static void              add_insn_to_hash_chain PARAMS ((CGEN_INSN_LIST *,
  35                                                          const CGEN_INSN *,
  36                                                          CGEN_INSN_LIST **,
  37                                                          unsigned int));
  38
  39 /* Return the number of decodable bits in this insn.  */
  40 static int
  41 count_decodable_bits (insn)
  42   const CGEN_INSN *insn;
  43 {
  44   unsigned mask = CGEN_INSN_BASE_MASK (insn);
  45   int bits = 0;
  46   int m;
  47   for (m = 1; m != 0; m <<= 1)
  48     {
  49       if (mask & m)
  50         ++bits;
  51     }
  52   return bits;
  53 }
  54
  55 /* Add an instruction to the hash chain.  */
  56 static void
  57 add_insn_to_hash_chain (hentbuf, insn, htable, hash)
  58      CGEN_INSN_LIST *hentbuf;
  59      const CGEN_INSN *insn;
  60      CGEN_INSN_LIST **htable;
  61      unsigned int hash;
  62 {
  63   CGEN_INSN_LIST *current_buf;
  64   CGEN_INSN_LIST *previous_buf;
  65   int insn_decodable_bits;
  66
  67   /* Add insns sorted by the number of decodable bits, in decreasing order.
  68      This ensures that any insn which is a special case of another will be
  69      checked first.  */
  70   insn_decodable_bits = count_decodable_bits (insn);
  71   previous_buf = NULL;
  72   for (current_buf = htable[hash]; current_buf != NULL;
  73        current_buf = current_buf->next)
  74     {
  75       int current_decodable_bits = count_decodable_bits (current_buf->insn);
  76       if (insn_decodable_bits >= current_decodable_bits)
  77         break;
  78       previous_buf = current_buf;
  79     }
  80
  81   /* Now insert the new insn.  */
  82   hentbuf->insn = insn;
  83   hentbuf->next = current_buf;
  84   if (previous_buf == NULL)
  85     htable[hash] = hentbuf;
  86   else
  87     previous_buf->next = hentbuf;
  88 }
  89
  90 /* Subroutine of build_dis_hash_table to add INSNS to the hash table.
  91
  92    COUNT is the number of elements in INSNS.
  93    ENTSIZE is sizeof (CGEN_IBASE) for the target.
  94    ??? No longer used but leave in for now.
  95    HTABLE points to the hash table.
  96    HENTBUF is a pointer to sufficiently large buffer of hash entries.
  97    The result is a pointer to the next entry to use.
  98
  99    The table is scanned backwards as additions are made to the front of the
 100    list and we want earlier ones to be prefered.  */
 101
 102 static CGEN_INSN_LIST *
 103 hash_insn_array (cd, insns, count, entsize, htable, hentbuf)
 104      CGEN_CPU_DESC cd;
 105      const CGEN_INSN * insns;
 106      int count;
 107      int entsize ATTRIBUTE_UNUSED;
 108      CGEN_INSN_LIST ** htable;
 109      CGEN_INSN_LIST * hentbuf;
 110 {
 111   int big_p = CGEN_CPU_ENDIAN (cd) == CGEN_ENDIAN_BIG;
 112   int i;
 113
 114   for (i = count - 1; i >= 0; --i, ++hentbuf)
 115     {
 116       unsigned int hash;
 117       char buf [4];
 118       unsigned long value;
 119       const CGEN_INSN *insn = &insns[i];
 120
 121       if (! (* cd->dis_hash_p) (insn))
 122         continue;
 123
 124       /* We don't know whether the target uses the buffer or the base insn
 125          to hash on, so set both up.  */
 126
 127       value = CGEN_INSN_BASE_VALUE (insn);
 128       bfd_put_bits ((bfd_vma) value,
 129                     buf,
 130                     CGEN_INSN_MASK_BITSIZE (insn),
 131                     big_p);
 132       hash = (* cd->dis_hash) (buf, value);
 133       add_insn_to_hash_chain (hentbuf, insn, htable, hash);
 134     }
 135
 136   return hentbuf;
 137 }
 138
 139 /* Subroutine of build_dis_hash_table to add INSNS to the hash table.
 140    This function is identical to hash_insn_array except the insns are
 141    in a list.  */
 142
 143 static CGEN_INSN_LIST *
 144 hash_insn_list (cd, insns, htable, hentbuf)
 145      CGEN_CPU_DESC cd;
 146      const CGEN_INSN_LIST *insns;
 147      CGEN_INSN_LIST **htable;
 148      CGEN_INSN_LIST *hentbuf;
 149 {
 150   int big_p = CGEN_CPU_ENDIAN (cd) == CGEN_ENDIAN_BIG;
 151   const CGEN_INSN_LIST *ilist;
 152
 153   for (ilist = insns; ilist != NULL; ilist = ilist->next, ++ hentbuf)
 154     {
 155       unsigned int hash;
 156       char buf[4];
 157       unsigned long value;
 158
 159       if (! (* cd->dis_hash_p) (ilist->insn))
 160         continue;
 161
 162       /* We don't know whether the target uses the buffer or the base insn
 163          to hash on, so set both up.  */
 164
 165       value = CGEN_INSN_BASE_VALUE (ilist->insn);
 166       bfd_put_bits((bfd_vma) value,
 167                    buf,
 168                    CGEN_INSN_MASK_BITSIZE (ilist->insn),
 169                    big_p);
 170       hash = (* cd->dis_hash) (buf, value);
 171       add_insn_to_hash_chain (hentbuf, ilist->insn, htable, hash);
 172     }
 173
 174   return hentbuf;
 175 }
 176
 177 /* Build the disassembler instruction hash table.  */
 178
 179 static void
 180 build_dis_hash_table (cd)
 181      CGEN_CPU_DESC cd;
 182 {
 183   int count = cgen_insn_count (cd) + cgen_macro_insn_count (cd);
 184   CGEN_INSN_TABLE *insn_table = & cd->insn_table;
 185   CGEN_INSN_TABLE *macro_insn_table = & cd->macro_insn_table;
 186   unsigned int hash_size = cd->dis_hash_size;
 187   CGEN_INSN_LIST *hash_entry_buf;
 188   CGEN_INSN_LIST **dis_hash_table;
 189   CGEN_INSN_LIST *dis_hash_table_entries;
 190
 191   /* The space allocated for the hash table consists of two parts:
 192      the hash table and the hash lists.  */
 193
 194   dis_hash_table = (CGEN_INSN_LIST **)
 195     xmalloc (hash_size * sizeof (CGEN_INSN_LIST *));
 196   memset (dis_hash_table, 0, hash_size * sizeof (CGEN_INSN_LIST *));
 197   dis_hash_table_entries = hash_entry_buf = (CGEN_INSN_LIST *)
 198     xmalloc (count * sizeof (CGEN_INSN_LIST));
 199
 200   /* Add compiled in insns.
 201      Don't include the first one as it is a reserved entry.  */
 202   /* ??? It was the end of all hash chains, and also the special
 203      "invalid insn" marker.  May be able to do it differently now.  */
 204
 205   hash_entry_buf = hash_insn_array (cd,
 206                                     insn_table->init_entries + 1,
 207                                     insn_table->num_init_entries - 1,
 208                                     insn_table->entry_size,
 209                                     dis_hash_table, hash_entry_buf);
 210
 211   /* Add compiled in macro-insns.  */
 212
 213   hash_entry_buf = hash_insn_array (cd, macro_insn_table->init_entries,
 214                                     macro_insn_table->num_init_entries,
 215                                     macro_insn_table->entry_size,
 216                                     dis_hash_table, hash_entry_buf);
 217
 218   /* Add runtime added insns.
 219      Later added insns will be prefered over earlier ones.  */
 220
 221   hash_entry_buf = hash_insn_list (cd, insn_table->new_entries,
 222                                    dis_hash_table, hash_entry_buf);
 223
 224   /* Add runtime added macro-insns.  */
 225
 226   hash_insn_list (cd, macro_insn_table->new_entries,
 227                   dis_hash_table, hash_entry_buf);
 228
 229   cd->dis_hash_table = dis_hash_table;
 230   cd->dis_hash_table_entries = dis_hash_table_entries;
 231 }
 232
 233 /* Return the first entry in the hash list for INSN.  */
 234
 235 CGEN_INSN_LIST *
 236 cgen_dis_lookup_insn (cd, buf, value)
 237      CGEN_CPU_DESC cd;
 238      const char * buf;
 239      CGEN_INSN_INT value;
 240 {
 241   unsigned int hash;
 242
 243   if (cd->dis_hash_table == NULL)
 244     build_dis_hash_table (cd);
 245
 246   hash = (* cd->dis_hash) (buf, value);
 247
 248   return cd->dis_hash_table[hash];
 249 }