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src/os_cpu/windows_x86/vm/assembler_windows_x86_32.cpp@a61af66fc99e (annotated)

src/os_cpu/windows_x86/vm/assembler_windows_x86_32.cpp

Sat, 01 Dec 2007 00:00:00 +0000

author

duke

date

Sat, 01 Dec 2007 00:00:00 +0000

changeset 435

a61af66fc99e

child 603

7793bd37a336

permissions

-rw-r--r--

Initial load

duke@435	1	/*
duke@435	2	* Copyright 1999-2003 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	#include "incls/_precompiled.incl"
duke@435	26	#include "incls/_assembler_windows_x86_32.cpp.incl"
duke@435	27
duke@435	28
duke@435	29	void MacroAssembler::int3() {
duke@435	30	emit_byte(0xCC);
duke@435	31	}
duke@435	32
duke@435	33	// The current scheme to accelerate access to the thread
duke@435	34	// pointer is to store the current thread in the os_exception_wrapper
duke@435	35	// and reference the current thread from stubs and compiled code
duke@435	36	// via the FS register. FS[0] contains a pointer to the structured
duke@435	37	// exception block which is actually a stack address. The first time
duke@435	38	// we call the os exception wrapper, we calculate and store the
duke@435	39	// offset from this exception block and use that offset here.
duke@435	40	//
duke@435	41	// The last mechanism we used was problematic in that the
duke@435	42	// the offset we had hard coded in the VM kept changing as Microsoft
duke@435	43	// evolved the OS.
duke@435	44	//
duke@435	45	// Warning: This mechanism assumes that we only attempt to get the
duke@435	46	// thread when we are nested below a call wrapper.
duke@435	47	//
duke@435	48	// movl reg, fs:[0] Get exeception pointer
duke@435	49	// movl reg, [reg + thread_ptr_offset] Load thread
duke@435	50	//
duke@435	51	void MacroAssembler::get_thread(Register thread) {
duke@435	52	// can't use ExternalAddress because it can't take NULL
duke@435	53	AddressLiteral null(0, relocInfo::none);
duke@435	54
duke@435	55	prefix(FS_segment);
duke@435	56	movptr(thread, null);
duke@435	57	assert(ThreadLocalStorage::get_thread_ptr_offset() != 0,
duke@435	58	"Thread Pointer Offset has not been initialized");
duke@435	59	movl(thread, Address(thread, ThreadLocalStorage::get_thread_ptr_offset()));
duke@435	60	}
duke@435	61
duke@435	62	bool MacroAssembler::needs_explicit_null_check(int offset) {
duke@435	63	return offset < 0 || (int)os::vm_page_size() <= offset;
duke@435	64	}