1 /*
 2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
 3  * Copyright (c) 2018, SAP SE. 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/cardTableModRefBS.hpp"
31 #include "gc/shared/cardTableModRefBSCodeGen.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 CardTableModRefBSCodeGen::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators, Register addr, Register count, Register preserve) {
46   CardTableModRefBS* ctbs = barrier_set_cast<CardTableModRefBS>(Universe::heap()->barrier_set());
47   CardTable* ct = ctbs->card_table();
48   assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "adjust this code");
49   assert_different_registers(addr, count, R0);
50 
51   Label Lskip_loop, Lstore_loop;
52 
53   if (UseConcMarkSweepGC) { __ membar(Assembler::StoreStore); }
54 
55   __ sldi_(count, count, LogBytesPerHeapOop);
56   __ beq(CCR0, Lskip_loop); // zero length
57   __ addi(count, count, -BytesPerHeapOop);
58   __ add(count, addr, count);
59   // Use two shifts to clear out those low order two bits! (Cannot opt. into 1.)
60   __ srdi(addr, addr, CardTable::card_shift);
61   __ srdi(count, count, CardTable::card_shift);
62   __ subf(count, addr, count);
63   __ add_const_optimized(addr, addr, (address)ct->byte_map_base(), R0);
64   __ addi(count, count, 1);
65   __ li(R0, 0);
66   __ mtctr(count);
67   // Byte store loop
68   __ bind(Lstore_loop);
69   __ stb(R0, 0, addr);
70   __ addi(addr, addr, 1);
71   __ bdnz(Lstore_loop);
72   __ bind(Lskip_loop);
73 }