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 (CGEN_CPU_DESC, const CGEN_INSN *, int, int, CGEN_INSN_LIST **, CGEN_INSN_LIST *);
31 static CGEN_INSN_LIST * hash_insn_list (CGEN_CPU_DESC, const CGEN_INSN_LIST *, CGEN_INSN_LIST **, CGEN_INSN_LIST *);
32 static void build_dis_hash_table (CGEN_CPU_DESC);
33 static int count_decodable_bits (const CGEN_INSN *);
34 static void add_insn_to_hash_chain (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
count_decodable_bits(const CGEN_INSN * insn)41 count_decodable_bits (const CGEN_INSN *insn)
42 {
43 unsigned mask = CGEN_INSN_BASE_MASK (insn);
44 int bits = 0;
45 int m;
46 for (m = 1; m != 0; m <<= 1)
47 {
48 if (mask & m)
49 ++bits;
50 }
51 return bits;
52 }
53
54 /* Add an instruction to the hash chain. */
55 static void
add_insn_to_hash_chain(CGEN_INSN_LIST * hentbuf,const CGEN_INSN * insn,CGEN_INSN_LIST ** htable,unsigned int hash)56 add_insn_to_hash_chain (CGEN_INSN_LIST *hentbuf,
57 const CGEN_INSN *insn,
58 CGEN_INSN_LIST **htable,
59 unsigned int hash)
60 {
61 CGEN_INSN_LIST *current_buf;
62 CGEN_INSN_LIST *previous_buf;
63 int insn_decodable_bits;
64
65 /* Add insns sorted by the number of decodable bits, in decreasing order.
66 This ensures that any insn which is a special case of another will be
67 checked first. */
68 insn_decodable_bits = count_decodable_bits (insn);
69 previous_buf = NULL;
70 for (current_buf = htable[hash]; current_buf != NULL;
71 current_buf = current_buf->next)
72 {
73 int current_decodable_bits = count_decodable_bits (current_buf->insn);
74 if (insn_decodable_bits >= current_decodable_bits)
75 break;
76 previous_buf = current_buf;
77 }
78
79 /* Now insert the new insn. */
80 hentbuf->insn = insn;
81 hentbuf->next = current_buf;
82 if (previous_buf == NULL)
83 htable[hash] = hentbuf;
84 else
85 previous_buf->next = hentbuf;
86 }
87
88 /* Subroutine of build_dis_hash_table to add INSNS to the hash table.
89
90 COUNT is the number of elements in INSNS.
91 ENTSIZE is sizeof (CGEN_IBASE) for the target.
92 ??? No longer used but leave in for now.
93 HTABLE points to the hash table.
94 HENTBUF is a pointer to sufficiently large buffer of hash entries.
95 The result is a pointer to the next entry to use.
96
97 The table is scanned backwards as additions are made to the front of the
98 list and we want earlier ones to be prefered. */
99
100 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)101 hash_insn_array (CGEN_CPU_DESC cd,
102 const CGEN_INSN * insns,
103 int count,
104 int entsize ATTRIBUTE_UNUSED,
105 CGEN_INSN_LIST ** htable,
106 CGEN_INSN_LIST * hentbuf)
107 {
108 int big_p = CGEN_CPU_ENDIAN (cd) == CGEN_ENDIAN_BIG;
109 int i;
110
111 for (i = count - 1; i >= 0; --i, ++hentbuf)
112 {
113 unsigned int hash;
114 char buf [4];
115 unsigned long value;
116 const CGEN_INSN *insn = &insns[i];
117
118 if (! (* cd->dis_hash_p) (insn))
119 continue;
120
121 /* We don't know whether the target uses the buffer or the base insn
122 to hash on, so set both up. */
123
124 value = CGEN_INSN_BASE_VALUE (insn);
125 bfd_put_bits ((bfd_vma) value,
126 buf,
127 CGEN_INSN_MASK_BITSIZE (insn),
128 big_p);
129 hash = (* cd->dis_hash) (buf, value);
130 add_insn_to_hash_chain (hentbuf, insn, htable, hash);
131 }
132
133 return hentbuf;
134 }
135
136 /* Subroutine of build_dis_hash_table to add INSNS to the hash table.
137 This function is identical to hash_insn_array except the insns are
138 in a list. */
139
140 static CGEN_INSN_LIST *
hash_insn_list(CGEN_CPU_DESC cd,const CGEN_INSN_LIST * insns,CGEN_INSN_LIST ** htable,CGEN_INSN_LIST * hentbuf)141 hash_insn_list (CGEN_CPU_DESC cd,
142 const CGEN_INSN_LIST *insns,
143 CGEN_INSN_LIST **htable,
144 CGEN_INSN_LIST *hentbuf)
145 {
146 int big_p = CGEN_CPU_ENDIAN (cd) == CGEN_ENDIAN_BIG;
147 const CGEN_INSN_LIST *ilist;
148
149 for (ilist = insns; ilist != NULL; ilist = ilist->next, ++ hentbuf)
150 {
151 unsigned int hash;
152 char buf[4];
153 unsigned long value;
154
155 if (! (* cd->dis_hash_p) (ilist->insn))
156 continue;
157
158 /* We don't know whether the target uses the buffer or the base insn
159 to hash on, so set both up. */
160
161 value = CGEN_INSN_BASE_VALUE (ilist->insn);
162 bfd_put_bits((bfd_vma) value,
163 buf,
164 CGEN_INSN_MASK_BITSIZE (ilist->insn),
165 big_p);
166 hash = (* cd->dis_hash) (buf, value);
167 add_insn_to_hash_chain (hentbuf, ilist->insn, htable, hash);
168 }
169
170 return hentbuf;
171 }
172
173 /* Build the disassembler instruction hash table. */
174
175 static void
build_dis_hash_table(CGEN_CPU_DESC cd)176 build_dis_hash_table (CGEN_CPU_DESC cd)
177 {
178 int count = cgen_insn_count (cd) + cgen_macro_insn_count (cd);
179 CGEN_INSN_TABLE *insn_table = & cd->insn_table;
180 CGEN_INSN_TABLE *macro_insn_table = & cd->macro_insn_table;
181 unsigned int hash_size = cd->dis_hash_size;
182 CGEN_INSN_LIST *hash_entry_buf;
183 CGEN_INSN_LIST **dis_hash_table;
184 CGEN_INSN_LIST *dis_hash_table_entries;
185
186 /* The space allocated for the hash table consists of two parts:
187 the hash table and the hash lists. */
188
189 dis_hash_table = (CGEN_INSN_LIST **)
190 xmalloc (hash_size * sizeof (CGEN_INSN_LIST *));
191 memset (dis_hash_table, 0, hash_size * sizeof (CGEN_INSN_LIST *));
192 dis_hash_table_entries = hash_entry_buf = (CGEN_INSN_LIST *)
193 xmalloc (count * sizeof (CGEN_INSN_LIST));
194
195 /* Add compiled in insns.
196 Don't include the first one as it is a reserved entry. */
197 /* ??? It was the end of all hash chains, and also the special
198 "invalid insn" marker. May be able to do it differently now. */
199
200 hash_entry_buf = hash_insn_array (cd,
201 insn_table->init_entries + 1,
202 insn_table->num_init_entries - 1,
203 insn_table->entry_size,
204 dis_hash_table, hash_entry_buf);
205
206 /* Add compiled in macro-insns. */
207
208 hash_entry_buf = hash_insn_array (cd, macro_insn_table->init_entries,
209 macro_insn_table->num_init_entries,
210 macro_insn_table->entry_size,
211 dis_hash_table, hash_entry_buf);
212
213 /* Add runtime added insns.
214 Later added insns will be prefered over earlier ones. */
215
216 hash_entry_buf = hash_insn_list (cd, insn_table->new_entries,
217 dis_hash_table, hash_entry_buf);
218
219 /* Add runtime added macro-insns. */
220
221 hash_insn_list (cd, macro_insn_table->new_entries,
222 dis_hash_table, hash_entry_buf);
223
224 cd->dis_hash_table = dis_hash_table;
225 cd->dis_hash_table_entries = dis_hash_table_entries;
226 }
227
228 /* Return the first entry in the hash list for INSN. */
229
230 CGEN_INSN_LIST *
cgen_dis_lookup_insn(CGEN_CPU_DESC cd,const char * buf,CGEN_INSN_INT value)231 cgen_dis_lookup_insn (CGEN_CPU_DESC cd, const char * buf, CGEN_INSN_INT value)
232 {
233 unsigned int hash;
234
235 if (cd->dis_hash_table == NULL)
236 build_dis_hash_table (cd);
237
238 hash = (* cd->dis_hash) (buf, value);
239
240 return cd->dis_hash_table[hash];
241 }
242