1 /*
 2  * Copyright (c) 2018, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  *
23  */
24 
25 #include "precompiled.hpp"
26 #include "asm/macroAssembler.inline.hpp"
27 #include "gc/shared/barrierSet.hpp"
28 #include "gc/shared/cardTable.hpp"
29 #include "gc/shared/cardTableModRefBS.hpp"
30 #include "gc/shared/cardTableModRefBSCodeGen.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "runtime/globals.hpp"
33 
34 #define __ masm->
35 
36 #ifdef PRODUCT
37 #define BLOCK_COMMENT(str) /* nothing */
38 #else
39 #define BLOCK_COMMENT(str) __ block_comment(str)
40 #endif
41 
42 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
43 
44 void CardTableModRefBSCodeGen::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
45                                                                 Register addr, Register count, Register tmp) {
46   BLOCK_COMMENT("CardTablePostBarrier");
47   CardTableModRefBS* ctbs = barrier_set_cast<CardTableModRefBS>(bs);
48   CardTable* ct = ctbs->card_table();
49   assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "adjust this code");
50 
51   Label L_cardtable_loop, L_done;
52 
53   __ cbz_32(count, L_done); // zero count - nothing to do
54 
55   __ add_ptr_scaled_int32(count, addr, count, LogBytesPerHeapOop);
56   __ sub(count, count, BytesPerHeapOop);                            // last addr
57 
58   __ logical_shift_right(addr, addr, CardTable::card_shift);
59   __ logical_shift_right(count, count, CardTable::card_shift);
60   __ sub(count, count, addr); // nb of cards
61 
62   // warning: Rthread has not been preserved
63   __ mov_address(tmp, (address) ct->byte_map_base(), symbolic_Relocation::card_table_reference);
64   __ add(addr,tmp, addr);
65 
66   Register zero = __ zero_register(tmp);
67 
68   __ BIND(L_cardtable_loop);
69   __ strb(zero, Address(addr, 1, post_indexed));
70   __ subs(count, count, 1);
71   __ b(L_cardtable_loop, ge);
72   __ BIND(L_done);
73 }