Mercurial > hg > graal-jvmci-8
annotate src/os_cpu/windows_x86/vm/assembler_windows_x86_32.cpp @ 168:7793bd37a336
6705887: Compressed Oops: generate x64 addressing and implicit null checks with narrow oops
Summary: Generate addresses and implicit null checks with narrow oops to avoid decoding.
Reviewed-by: jrose, never
author | kvn |
---|---|
date | Thu, 29 May 2008 12:04:14 -0700 |
parents | a61af66fc99e |
children | d1605aabd0a1 |
rev | line source |
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0 | 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 | |
168
7793bd37a336
6705887: Compressed Oops: generate x64 addressing and implicit null checks with narrow oops
kvn
parents:
0
diff
changeset
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62 bool MacroAssembler::needs_explicit_null_check(intptr_t offset) { |
0 | 63 return offset < 0 || (int)os::vm_page_size() <= offset; |
64 } |