1 
 2 /*
 3  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
 4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 5  *
 6  * This code is free software; you can redistribute it and/or modify it
 7  * under the terms of the GNU General Public License version 2 only, as
 8  * published by the Free Software Foundation.
 9  *
10  * This code is distributed in the hope that it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13  * version 2 for more details (a copy is included in the LICENSE file that
14  * accompanied this code).
15  *
16  * You should have received a copy of the GNU General Public License version
17  * 2 along with this work; if not, write to the Free Software Foundation,
18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19  *
20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21  * or visit www.oracle.com if you need additional information or have any
22  * questions.
23  *
24  */
25 
26 #include "precompiled.hpp"
27 #include "asm/macroAssembler.inline.hpp"
28 #include "gc/shared/barrierSet.hpp"
29 #include "gc/shared/cardTable.hpp"
30 #include "gc/shared/cardTableBarrierSet.hpp"
31 #include "gc/shared/cardTableBarrierSetAssembler.hpp"
32 #include "gc/shared/collectedHeap.hpp"
33 #include "interpreter/interp_masm.hpp"
34 
35 #define __ masm->
36 
37 #ifdef PRODUCT
38 #define BLOCK_COMMENT(str) /* nothing */
39 #else
40 #define BLOCK_COMMENT(str) __ block_comment(str)
41 #endif
42 
43 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
44 
45 void CardTableBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
46                                                                     Register addr, Register count, Register tmp) {
47   CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(Universe::heap()->barrier_set());
48   CardTable* ct = ctbs->card_table();
49   assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "adjust this code");
50   assert_different_registers(addr, count, tmp);
51 
52   Label L_loop, L_done;
53 
54   __ cmp_and_br_short(count, 0, Assembler::equal, Assembler::pt, L_done); // zero count - nothing to do
55 
56   __ sll_ptr(count, LogBytesPerHeapOop, count);
57   __ sub(count, BytesPerHeapOop, count);
58   __ add(count, addr, count);
59   // Use two shifts to clear out those low order two bits! (Cannot opt. into 1.)
60   __ srl_ptr(addr, CardTable::card_shift, addr);
61   __ srl_ptr(count, CardTable::card_shift, count);
62   __ sub(count, addr, count);
63   AddressLiteral rs(ct->byte_map_base());
64   __ set(rs, tmp);
65   __ BIND(L_loop);
66   __ stb(G0, tmp, addr);
67   __ subcc(count, 1, count);
68   __ brx(Assembler::greaterEqual, false, Assembler::pt, L_loop);
69   __ delayed()->add(addr, 1, addr);
70 
71   __ BIND(L_done);
72 }