Annotation of src/external/gpl3/binutils.old/dist/opcodes/cgen-dis.c, Revision 1.6
1.1 christos 1: /* CGEN generic disassembler support code.
1.6 ! christos 2: Copyright (C) 1996-2018 Free Software Foundation, Inc.
1.1 christos 3:
4: This file is part of libopcodes.
5:
6: This library 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, or (at your option)
9: any later version.
10:
11: It is distributed in the hope that it will be useful, but WITHOUT
12: ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14: License for more details.
15:
16: You should have received a copy of the GNU General Public License along
17: with this program; if not, write to the Free Software Foundation, Inc.,
18: 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
19:
20: #include "sysdep.h"
21: #include <stdio.h>
22: #include "ansidecl.h"
23: #include "libiberty.h"
24: #include "bfd.h"
25: #include "symcat.h"
26: #include "opcode/cgen.h"
27:
28: static CGEN_INSN_LIST * hash_insn_array (CGEN_CPU_DESC, const CGEN_INSN *, int, int, CGEN_INSN_LIST **, CGEN_INSN_LIST *);
29: static CGEN_INSN_LIST * hash_insn_list (CGEN_CPU_DESC, const CGEN_INSN_LIST *, CGEN_INSN_LIST **, CGEN_INSN_LIST *);
30: static void build_dis_hash_table (CGEN_CPU_DESC);
31: static int count_decodable_bits (const CGEN_INSN *);
32: static void add_insn_to_hash_chain (CGEN_INSN_LIST *,
33: const CGEN_INSN *,
34: CGEN_INSN_LIST **,
35: unsigned int);
36:
37: /* Return the number of decodable bits in this insn. */
38: static int
39: count_decodable_bits (const CGEN_INSN *insn)
40: {
41: unsigned mask = CGEN_INSN_BASE_MASK (insn);
42: int bits = 0;
1.5 christos 43: unsigned m;
44:
1.1 christos 45: for (m = 1; m != 0; m <<= 1)
46: {
47: if (mask & m)
48: ++bits;
49: }
50: return bits;
51: }
52:
1.3 christos 53: /* Add an instruction to the hash chain. */
1.1 christos 54: static void
55: add_insn_to_hash_chain (CGEN_INSN_LIST *hentbuf,
56: const CGEN_INSN *insn,
57: CGEN_INSN_LIST **htable,
58: unsigned int hash)
59: {
60: CGEN_INSN_LIST *current_buf;
61: CGEN_INSN_LIST *previous_buf;
62: int insn_decodable_bits;
63:
64: /* Add insns sorted by the number of decodable bits, in decreasing order.
65: This ensures that any insn which is a special case of another will be
66: checked first. */
67: insn_decodable_bits = count_decodable_bits (insn);
68: previous_buf = NULL;
69: for (current_buf = htable[hash]; current_buf != NULL;
70: current_buf = current_buf->next)
71: {
72: int current_decodable_bits = count_decodable_bits (current_buf->insn);
73: if (insn_decodable_bits >= current_decodable_bits)
74: break;
75: previous_buf = current_buf;
76: }
77:
78: /* Now insert the new insn. */
79: hentbuf->insn = insn;
80: hentbuf->next = current_buf;
81: if (previous_buf == NULL)
82: htable[hash] = hentbuf;
83: else
84: previous_buf->next = hentbuf;
85: }
86:
87: /* Subroutine of build_dis_hash_table to add INSNS to the hash table.
88:
89: COUNT is the number of elements in INSNS.
90: ENTSIZE is sizeof (CGEN_IBASE) for the target.
91: ??? No longer used but leave in for now.
92: HTABLE points to the hash table.
93: HENTBUF is a pointer to sufficiently large buffer of hash entries.
94: The result is a pointer to the next entry to use.
95:
96: The table is scanned backwards as additions are made to the front of the
97: list and we want earlier ones to be prefered. */
98:
99: static CGEN_INSN_LIST *
100: hash_insn_array (CGEN_CPU_DESC cd,
101: const CGEN_INSN * insns,
102: int count,
103: int entsize ATTRIBUTE_UNUSED,
104: CGEN_INSN_LIST ** htable,
105: CGEN_INSN_LIST * hentbuf)
106: {
1.3 christos 107: int big_p = CGEN_CPU_INSN_ENDIAN (cd) == CGEN_ENDIAN_BIG;
1.1 christos 108: int i;
109:
110: for (i = count - 1; i >= 0; --i, ++hentbuf)
111: {
112: unsigned int hash;
113: char buf [4];
114: unsigned long value;
115: const CGEN_INSN *insn = &insns[i];
116:
117: if (! (* cd->dis_hash_p) (insn))
118: continue;
119:
120: /* We don't know whether the target uses the buffer or the base insn
121: to hash on, so set both up. */
122:
123: value = CGEN_INSN_BASE_VALUE (insn);
124: bfd_put_bits ((bfd_vma) value,
125: buf,
126: CGEN_INSN_MASK_BITSIZE (insn),
127: big_p);
128: hash = (* cd->dis_hash) (buf, value);
129: add_insn_to_hash_chain (hentbuf, insn, htable, hash);
130: }
131:
132: return hentbuf;
133: }
134:
135: /* Subroutine of build_dis_hash_table to add INSNS to the hash table.
136: This function is identical to hash_insn_array except the insns are
137: in a list. */
138:
139: static CGEN_INSN_LIST *
140: hash_insn_list (CGEN_CPU_DESC cd,
141: const CGEN_INSN_LIST *insns,
142: CGEN_INSN_LIST **htable,
143: CGEN_INSN_LIST *hentbuf)
144: {
1.3 christos 145: int big_p = CGEN_CPU_INSN_ENDIAN (cd) == CGEN_ENDIAN_BIG;
1.1 christos 146: const CGEN_INSN_LIST *ilist;
147:
148: for (ilist = insns; ilist != NULL; ilist = ilist->next, ++ hentbuf)
149: {
150: unsigned int hash;
151: char buf[4];
152: unsigned long value;
153:
154: if (! (* cd->dis_hash_p) (ilist->insn))
155: continue;
156:
157: /* We don't know whether the target uses the buffer or the base insn
158: to hash on, so set both up. */
159:
160: value = CGEN_INSN_BASE_VALUE (ilist->insn);
161: bfd_put_bits((bfd_vma) value,
162: buf,
163: CGEN_INSN_MASK_BITSIZE (ilist->insn),
164: big_p);
165: hash = (* cd->dis_hash) (buf, value);
166: add_insn_to_hash_chain (hentbuf, ilist->insn, htable, hash);
167: }
168:
169: return hentbuf;
170: }
171:
172: /* Build the disassembler instruction hash table. */
173:
174: static void
175: build_dis_hash_table (CGEN_CPU_DESC cd)
176: {
177: int count = cgen_insn_count (cd) + cgen_macro_insn_count (cd);
178: CGEN_INSN_TABLE *insn_table = & cd->insn_table;
179: CGEN_INSN_TABLE *macro_insn_table = & cd->macro_insn_table;
180: unsigned int hash_size = cd->dis_hash_size;
181: CGEN_INSN_LIST *hash_entry_buf;
182: CGEN_INSN_LIST **dis_hash_table;
183: CGEN_INSN_LIST *dis_hash_table_entries;
184:
185: /* The space allocated for the hash table consists of two parts:
186: the hash table and the hash lists. */
187:
188: dis_hash_table = (CGEN_INSN_LIST **)
189: xmalloc (hash_size * sizeof (CGEN_INSN_LIST *));
190: memset (dis_hash_table, 0, hash_size * sizeof (CGEN_INSN_LIST *));
191: dis_hash_table_entries = hash_entry_buf = (CGEN_INSN_LIST *)
192: xmalloc (count * sizeof (CGEN_INSN_LIST));
193:
194: /* Add compiled in insns.
195: Don't include the first one as it is a reserved entry. */
196: /* ??? It was the end of all hash chains, and also the special
197: "invalid insn" marker. May be able to do it differently now. */
198:
199: hash_entry_buf = hash_insn_array (cd,
200: insn_table->init_entries + 1,
201: insn_table->num_init_entries - 1,
202: insn_table->entry_size,
203: dis_hash_table, hash_entry_buf);
204:
205: /* Add compiled in macro-insns. */
206:
207: hash_entry_buf = hash_insn_array (cd, macro_insn_table->init_entries,
208: macro_insn_table->num_init_entries,
209: macro_insn_table->entry_size,
210: dis_hash_table, hash_entry_buf);
211:
212: /* Add runtime added insns.
213: Later added insns will be prefered over earlier ones. */
214:
215: hash_entry_buf = hash_insn_list (cd, insn_table->new_entries,
216: dis_hash_table, hash_entry_buf);
217:
218: /* Add runtime added macro-insns. */
219:
220: hash_insn_list (cd, macro_insn_table->new_entries,
221: dis_hash_table, hash_entry_buf);
222:
223: cd->dis_hash_table = dis_hash_table;
224: cd->dis_hash_table_entries = dis_hash_table_entries;
225: }
226:
227: /* Return the first entry in the hash list for INSN. */
228:
229: CGEN_INSN_LIST *
230: cgen_dis_lookup_insn (CGEN_CPU_DESC cd, const char * buf, CGEN_INSN_INT value)
231: {
232: unsigned int hash;
233:
234: if (cd->dis_hash_table == NULL)
235: build_dis_hash_table (cd);
236:
237: hash = (* cd->dis_hash) (buf, value);
238:
239: return cd->dis_hash_table[hash];
240: }
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