hotspot/src/os_cpu/windows_x86/vm/assembler_windows_x86_32.cpp
changeset 1 489c9b5090e2
child 594 9f4474e5dbaf
equal deleted inserted replaced
0:fd16c54261b3 1:489c9b5090e2
       
     1 /*
       
     2  * Copyright 1999-2003 Sun Microsystems, Inc.  All Rights Reserved.
       
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       
     4  *
       
     5  * This code is free software; you can redistribute it and/or modify it
       
     6  * under the terms of the GNU General Public License version 2 only, as
       
     7  * published by the Free Software Foundation.
       
     8  *
       
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
       
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
       
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
       
    12  * version 2 for more details (a copy is included in the LICENSE file that
       
    13  * accompanied this code).
       
    14  *
       
    15  * You should have received a copy of the GNU General Public License version
       
    16  * 2 along with this work; if not, write to the Free Software Foundation,
       
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
       
    18  *
       
    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
       
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
       
    21  * have any questions.
       
    22  *
       
    23  */
       
    24 
       
    25 #include "incls/_precompiled.incl"
       
    26 #include "incls/_assembler_windows_x86_32.cpp.incl"
       
    27 
       
    28 
       
    29 void MacroAssembler::int3() {
       
    30   emit_byte(0xCC);
       
    31 }
       
    32 
       
    33 //  The current scheme to accelerate access to the thread
       
    34 //  pointer is to store the current thread in the os_exception_wrapper
       
    35 //  and reference the current thread from stubs and compiled code
       
    36 //  via the FS register.  FS[0] contains a pointer to the structured
       
    37 //  exception block which is actually a stack address.  The first time
       
    38 //  we call the os exception wrapper, we calculate and store the
       
    39 //  offset from this exception block and use that offset here.
       
    40 //
       
    41 //  The last mechanism we used was problematic in that the
       
    42 //  the offset we had hard coded in the VM kept changing as Microsoft
       
    43 //  evolved the OS.
       
    44 //
       
    45 // Warning: This mechanism assumes that we only attempt to get the
       
    46 //          thread when we are nested below a call wrapper.
       
    47 //
       
    48 // movl reg, fs:[0]                        Get exeception pointer
       
    49 // movl reg, [reg + thread_ptr_offset]     Load thread
       
    50 //
       
    51 void MacroAssembler::get_thread(Register thread) {
       
    52   // can't use ExternalAddress because it can't take NULL
       
    53   AddressLiteral null(0, relocInfo::none);
       
    54 
       
    55   prefix(FS_segment);
       
    56   movptr(thread, null);
       
    57   assert(ThreadLocalStorage::get_thread_ptr_offset() != 0,
       
    58          "Thread Pointer Offset has not been initialized");
       
    59   movl(thread, Address(thread, ThreadLocalStorage::get_thread_ptr_offset()));
       
    60 }
       
    61 
       
    62 bool MacroAssembler::needs_explicit_null_check(int offset) {
       
    63   return offset < 0 || (int)os::vm_page_size() <= offset;
       
    64 }