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 "interpreter/interp_masm.hpp"
33 
34 #define __ masm->
35 
36 void CardTableModRefBSCodeGen::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
37                                                                 Register start, Register end, Register scratch, RegSet saved_regs) {
38 
39   BarrierSet* bs = Universe::heap()->barrier_set();
40   CardTableModRefBS* ctbs = barrier_set_cast<CardTableModRefBS>(bs);
41   CardTable* ct = ctbs->card_table();
42   assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "adjust this code");
43 
44   Label L_loop;
45 
46   __ lsr(start, start, CardTable::card_shift);
47   __ lsr(end, end, CardTable::card_shift);
48   __ sub(end, end, start); // number of bytes to copy
49 
50   const Register count = end; // 'end' register contains bytes count now
51   __ load_byte_map_base(scratch);
52   __ add(start, start, scratch);
53   if (UseConcMarkSweepGC) {
54     __ membar(__ StoreStore);
55   }
56   __ bind(L_loop);
57   __ strb(zr, Address(start, count));
58   __ subs(count, count, 1);
59   __ br(Assembler::GE, L_loop);
60 }