Ziele Untersuchung
mit Columbo Integrität von
Datenbanken Interaktion und
Portierbarkeit Ergonomie der
Schnittstellen

Angebot Produkte Projekt Beratung

Mittel Analytik Modellierung Sprachen Algebra Logik Hardware Denken Kreativität

Zusammenhänge Gesellschaft Wirtschaft Branche Firma


products/sources/formale Sprachen/Java/Openjdk/src/hotspot/cpu/arm/ (Sun/Oracle ^©) Datei vom 13.11.2022 mit Größe 4 kB

Quelle c2_MacroAssembler_arm.cpp Sprache: C

/*
* Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/

#include "precompiled.hpp"
#include "asm/assembler.hpp"
#include "asm/assembler.inline.hpp"
#include "opto/c2_MacroAssembler.hpp"
#include "runtime/basicLock.hpp"

// TODO: 8 bytes at a time? pre-fetch?
// Compare char[] arrays aligned to 4 bytes.
void C2_MacroAssembler::char_arrays_equals(Register ary1, Register ary2,
                                           Register limit, Register result,
                                           Register chr1, Register chr2, Label& Ldone) {
  Label Lvector, Lloop;

  // if (ary1 == ary2)
  //     return true;
  cmpoop(ary1, ary2);
  b(Ldone, eq);

  // Note: limit contains number of bytes (2*char_elements) != 0.
  tst(limit, 0x2); // trailing character ?
  b(Lvector, eq);

  // compare the trailing char
  sub(limit, limit, sizeof(jchar));
  ldrh(chr1, Address(ary1, limit));
  ldrh(chr2, Address(ary2, limit));
  cmp(chr1, chr2);
  mov(result, 0, ne);     // not equal
  b(Ldone, ne);

  // only one char ?
  tst(limit, limit);
  mov(result, 1, eq);
  b(Ldone, eq);

  // word by word compare, don't need alignment check
  bind(Lvector);

  // Shift ary1 and ary2 to the end of the arrays, negate limit
  add(ary1, limit, ary1);
  add(ary2, limit, ary2);
  neg(limit, limit);

  bind(Lloop);
  ldr_u32(chr1, Address(ary1, limit));
  ldr_u32(chr2, Address(ary2, limit));
  cmp_32(chr1, chr2);
  mov(result, 0, ne);     // not equal
  b(Ldone, ne);
  adds(limit, limit, 2*sizeof(jchar));
  b(Lloop, ne);

  // Caller should set it:
  // mov(result_reg, 1);  //equal
}

void C2_MacroAssembler::fast_lock(Register Roop, Register Rbox, Register Rscratch, Register Rscratch2) {
  assert(VM_Version::supports_ldrex(), "unsupported, yet?");

  Register Rmark      = Rscratch2;

  assert(Roop != Rscratch, "");
  assert(Roop != Rmark, "");
  assert(Rbox != Rscratch, "");
  assert(Rbox != Rmark, "");

  Label fast_lock, done;

  if (DiagnoseSyncOnValueBasedClasses != 0) {
    load_klass(Rscratch, Roop);
    ldr_u32(Rscratch, Address(Rscratch, Klass::access_flags_offset()));
    tst(Rscratch, JVM_ACC_IS_VALUE_BASED_CLASS);
    b(done, ne);
  }

  ldr(Rmark, Address(Roop, oopDesc::mark_offset_in_bytes()));
  tst(Rmark, markWord::unlocked_value);
  b(fast_lock, ne);

  // Check for recursive lock
  // See comments in InterpreterMacroAssembler::lock_object for
  // explanations on the fast recursive locking check.
  // -1- test low 2 bits
  movs(Rscratch, AsmOperand(Rmark, lsl, 30));
  // -2- test (hdr - SP) if the low two bits are 0
  sub(Rscratch, Rmark, SP, eq);
  movs(Rscratch, AsmOperand(Rscratch, lsr, exact_log2(os::vm_page_size())), eq);
  // If still 'eq' then recursive locking OK
  // set to zero if recursive lock, set to non zero otherwise (see discussion in JDK-8153107)
  str(Rscratch, Address(Rbox, BasicLock::displaced_header_offset_in_bytes()));
  b(done);

  bind(fast_lock);
  str(Rmark, Address(Rbox, BasicLock::displaced_header_offset_in_bytes()));

  bool allow_fallthrough_on_failure = true;
  bool one_shot = true;
  cas_for_lock_acquire(Rmark, Rbox, Roop, Rscratch, done, allow_fallthrough_on_failure, one_shot);

  bind(done);

  // At this point flags are set as follows:
  //  EQ -> Success
  //  NE -> Failure, branch to slow path
}

void C2_MacroAssembler::fast_unlock(Register Roop, Register Rbox, Register Rscratch, Register Rscratch2) {
  assert(VM_Version::supports_ldrex(), "unsupported, yet?");

  Register Rmark      = Rscratch2;

  assert(Roop != Rscratch, "");
  assert(Roop != Rmark, "");
  assert(Rbox != Rscratch, "");
  assert(Rbox != Rmark, "");

  Label done;

  ldr(Rmark, Address(Rbox, BasicLock::displaced_header_offset_in_bytes()));
  // If hdr is NULL, we've got recursive locking and there's nothing more to do
  cmp(Rmark, 0);
  b(done, eq);

  // Restore the object header
  bool allow_fallthrough_on_failure = true;
  bool one_shot = true;
  cas_for_lock_release(Rmark, Rbox, Roop, Rscratch, done, allow_fallthrough_on_failure, one_shot);

  bind(done);
}

quality98%

¤ Dauer der Verarbeitung: 0.1 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.