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/* CGEN generic disassembler support code.
Copyright (C) 1996-2021 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"
#include "disassemble.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);
#if GCC_VERSION >= 3004
return __builtin_popcount (mask);
#else
int bits = 0;
unsigned m;
for (m = 1; m != 0; m <<= 1)
{
if (mask & m)
++bits;
}
return bits;
#endif
}
/* 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 preferred. */
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 [8];
unsigned long value;
const CGEN_INSN *insn = &insns[i];
size_t size;
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);
size = CGEN_INSN_MASK_BITSIZE (insn);
OPCODES_ASSERT (size <= sizeof (buf) * 8);
bfd_put_bits ((bfd_vma) value, buf, size, 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 preferred 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];
}
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