cgen-dis.c revision 38889 
1/* CGEN generic disassembler support code.
2
3   Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
4
5   This file is part of the GNU Binutils and GDB, the GNU debugger.
6
7   This program is free software; you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 2, or (at your option)
10   any later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License along
18   with this program; if not, write to the Free Software Foundation, Inc.,
19   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
20
21#include "sysdep.h"
22#include <stdio.h>
23#include "ansidecl.h"
24#include "libiberty.h"
25#include "bfd.h"
26#include "symcat.h"
27#include "opcode/cgen.h"
28
29/* This is not published as part of the public interface so we don't
30   declare this in cgen.h.  */
31extern CGEN_OPCODE_DATA * cgen_current_opcode_data;
32
33/* Disassembler instruction hash table.  */
34static CGEN_INSN_LIST ** dis_hash_table;
35
36void
37cgen_dis_init ()
38{
39  if (dis_hash_table)
40    {
41      free (dis_hash_table);
42      dis_hash_table = NULL;
43    }
44}
45
46/* Build the disassembler instruction hash table.  */
47
48static void
49build_dis_hash_table ()
50{
51  int bigend = cgen_current_endian == CGEN_ENDIAN_BIG;
52  unsigned int hash;
53  char buf [4];
54  unsigned long value;
55  int count = cgen_insn_count ();
56  CGEN_OPCODE_DATA * data = cgen_current_opcode_data;
57  CGEN_INSN_TABLE * insn_table = data->insn_table;
58  unsigned int entry_size = insn_table->entry_size;
59  unsigned int hash_size = insn_table->dis_hash_table_size;
60  const CGEN_INSN * insn;
61  CGEN_INSN_LIST * insn_lists;
62  CGEN_INSN_LIST * new_insns;
63
64  /* The space allocated for the hash table consists of two parts:
65     the hash table and the hash lists.  */
66
67  dis_hash_table = (CGEN_INSN_LIST **)
68    xmalloc (hash_size * sizeof (CGEN_INSN_LIST *)
69	     + count * sizeof (CGEN_INSN_LIST));
70  memset (dis_hash_table, 0,
71	  hash_size * sizeof (CGEN_INSN_LIST *)
72	  + count * sizeof (CGEN_INSN_LIST));
73  insn_lists = (CGEN_INSN_LIST *) (dis_hash_table + hash_size);
74
75  /* Add compiled in insns.
76     The table is scanned backwards as later additions are inserted in
77     front of earlier ones and we want earlier ones to be prefered.
78     We stop at the first one as it is a reserved entry.
79     This is a bit tricky as the attribute member of CGEN_INSN is variable
80     among architectures.  This code could be moved to cgen-asm.in, but
81     I prefer to keep it here for now.  */
82
83  for (insn = (CGEN_INSN *)
84       ((char *) insn_table->init_entries
85	+ entry_size * (insn_table->num_init_entries - 1));
86       insn > insn_table->init_entries;
87       insn = (CGEN_INSN *) ((char *) insn - entry_size), ++ insn_lists)
88    {
89      /* We don't know whether the target uses the buffer or the base insn
90	 to hash on, so set both up.  */
91      value = CGEN_INSN_VALUE (insn);
92      switch (CGEN_INSN_MASK_BITSIZE (insn))
93	{
94	case 8:
95	  buf[0] = value;
96	  break;
97	case 16:
98	  if (bigend)
99	    bfd_putb16 ((bfd_vma) value, buf);
100	  else
101	    bfd_putl16 ((bfd_vma) value, buf);
102	  break;
103	case 32:
104	  if (bigend)
105	    bfd_putb32 ((bfd_vma) value, buf);
106	  else
107	    bfd_putl32 ((bfd_vma) value, buf);
108	  break;
109	default:
110	  abort ();
111	}
112
113      hash = insn_table->dis_hash (buf, value);
114
115      insn_lists->next = dis_hash_table [hash];
116      insn_lists->insn = insn;
117
118      dis_hash_table [hash] = insn_lists;
119    }
120
121  /* Add runtime added insns.
122     ??? Currently later added insns will be prefered over earlier ones.
123     Not sure this is a bug or not.  */
124  for (new_insns = insn_table->new_entries;
125       new_insns != NULL;
126       new_insns = new_insns->next, ++ insn_lists)
127    {
128      /* We don't know whether the target uses the buffer or the base insn
129	 to hash on, so set both up.  */
130      value = CGEN_INSN_VALUE (new_insns->insn);
131      switch (CGEN_INSN_MASK_BITSIZE (new_insns->insn))
132	{
133	case 8:
134	  buf[0] = value;
135	  break;
136	case 16:
137	  if (bigend)
138	    bfd_putb16 ((bfd_vma) value, buf);
139	  else
140	    bfd_putl16 ((bfd_vma) value, buf);
141	  break;
142	case 32:
143	  if (bigend)
144	    bfd_putb32 ((bfd_vma) value, buf);
145	  else
146	    bfd_putl32 ((bfd_vma) value, buf);
147	  break;
148	default:
149	  abort ();
150	}
151
152      hash = insn_table->dis_hash (buf, value);
153
154      insn_lists->next = dis_hash_table [hash];
155      insn_lists->insn = new_insns->insn;
156
157      dis_hash_table [hash] = insn_lists;
158    }
159}
160
161/* Return the first entry in the hash list for INSN.  */
162
163CGEN_INSN_LIST *
164cgen_dis_lookup_insn (buf, value)
165     const char * buf;
166     unsigned long value;
167{
168  unsigned int hash;
169
170  if (dis_hash_table == NULL)
171    build_dis_hash_table ();
172
173  hash = cgen_current_opcode_data->insn_table->dis_hash (buf, value);
174
175  return dis_hash_table [hash];
176}
177