102
103 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
104 CardTable* ct = ctbs->card_table();
105 assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "Adjust store check code");
106
107 // Load card table base address.
108
109 /* Performance note.
110
111 There is an alternative way of loading card table base address
112 from thread descriptor, which may look more efficient:
113
114 ldr(card_table_base, Address(Rthread, JavaThread::card_table_base_offset()));
115
116 However, performance measurements of micro benchmarks and specJVM98
117 showed that loading of card table base from thread descriptor is
118 7-18% slower compared to loading of literal embedded into the code.
119 Possible cause is a cache miss (card table base address resides in a
120 rarely accessed area of thread descriptor).
121 */
122 // TODO-AARCH64 Investigate if mov_slow is faster than ldr from Rthread on AArch64
123 __ mov_address(card_table_base, (address)ct->byte_map_base(), symbolic_Relocation::card_table_reference);
124 }
125
126 // The 2nd part of the store check.
127 void CardTableBarrierSetAssembler::store_check_part2(MacroAssembler* masm, Register obj, Register card_table_base, Register tmp) {
128 assert_different_registers(obj, card_table_base, tmp);
129
130 BarrierSet* bs = BarrierSet::barrier_set();
131 assert(bs->kind() == BarrierSet::CardTableBarrierSet,
132 "Wrong barrier set kind");
133
134 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
135 CardTable* ct = ctbs->card_table();
136 assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "Adjust store check code");
137
138 assert(CardTable::dirty_card_val() == 0, "Dirty card value must be 0 due to optimizations.");
139 #ifdef AARCH64
140 add(card_table_base, card_table_base, AsmOperand(obj, lsr, CardTable::card_shift));
141 Address card_table_addr(card_table_base);
142 #else
143 Address card_table_addr(card_table_base, obj, lsr, CardTable::card_shift);
144 #endif
145
146 if (UseCondCardMark) {
147 if (ct->scanned_concurrently()) {
148 __ membar(MacroAssembler::Membar_mask_bits(MacroAssembler::StoreLoad), noreg);
149 }
150 Label already_dirty;
151
152 __ ldrb(tmp, card_table_addr);
153 __ cbz(tmp, already_dirty);
154
155 set_card(masm, card_table_base, card_table_addr, tmp);
156 __ bind(already_dirty);
157
158 } else {
159 if (ct->scanned_concurrently()) {
160 __ membar(MacroAssembler::Membar_mask_bits(MacroAssembler::StoreStore), noreg);
161 }
162 set_card(masm, card_table_base, card_table_addr, tmp);
163 }
164 }
165
166 void CardTableBarrierSetAssembler::set_card(MacroAssembler* masm, Register card_table_base, Address card_table_addr, Register tmp) {
167 #ifdef AARCH64
168 strb(ZR, card_table_addr);
169 #else
170 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(BarrierSet::barrier_set());
171 CardTable* ct = ctbs->card_table();
172 if ((((uintptr_t)ct->byte_map_base() & 0xff) == 0)) {
173 // Card table is aligned so the lowest byte of the table address base is zero.
174 // This works only if the code is not saved for later use, possibly
175 // in a context where the base would no longer be aligned.
176 __ strb(card_table_base, card_table_addr);
177 } else {
178 __ mov(tmp, 0);
179 __ strb(tmp, card_table_addr);
180 }
181 #endif // AARCH64
182 }
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102
103 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
104 CardTable* ct = ctbs->card_table();
105 assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "Adjust store check code");
106
107 // Load card table base address.
108
109 /* Performance note.
110
111 There is an alternative way of loading card table base address
112 from thread descriptor, which may look more efficient:
113
114 ldr(card_table_base, Address(Rthread, JavaThread::card_table_base_offset()));
115
116 However, performance measurements of micro benchmarks and specJVM98
117 showed that loading of card table base from thread descriptor is
118 7-18% slower compared to loading of literal embedded into the code.
119 Possible cause is a cache miss (card table base address resides in a
120 rarely accessed area of thread descriptor).
121 */
122 __ mov_address(card_table_base, (address)ct->byte_map_base(), symbolic_Relocation::card_table_reference);
123 }
124
125 // The 2nd part of the store check.
126 void CardTableBarrierSetAssembler::store_check_part2(MacroAssembler* masm, Register obj, Register card_table_base, Register tmp) {
127 assert_different_registers(obj, card_table_base, tmp);
128
129 BarrierSet* bs = BarrierSet::barrier_set();
130 assert(bs->kind() == BarrierSet::CardTableBarrierSet,
131 "Wrong barrier set kind");
132
133 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
134 CardTable* ct = ctbs->card_table();
135 assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "Adjust store check code");
136
137 assert(CardTable::dirty_card_val() == 0, "Dirty card value must be 0 due to optimizations.");
138 Address card_table_addr(card_table_base, obj, lsr, CardTable::card_shift);
139
140 if (UseCondCardMark) {
141 if (ct->scanned_concurrently()) {
142 __ membar(MacroAssembler::Membar_mask_bits(MacroAssembler::StoreLoad), noreg);
143 }
144 Label already_dirty;
145
146 __ ldrb(tmp, card_table_addr);
147 __ cbz(tmp, already_dirty);
148
149 set_card(masm, card_table_base, card_table_addr, tmp);
150 __ bind(already_dirty);
151
152 } else {
153 if (ct->scanned_concurrently()) {
154 __ membar(MacroAssembler::Membar_mask_bits(MacroAssembler::StoreStore), noreg);
155 }
156 set_card(masm, card_table_base, card_table_addr, tmp);
157 }
158 }
159
160 void CardTableBarrierSetAssembler::set_card(MacroAssembler* masm, Register card_table_base, Address card_table_addr, Register tmp) {
161 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(BarrierSet::barrier_set());
162 CardTable* ct = ctbs->card_table();
163 if ((((uintptr_t)ct->byte_map_base() & 0xff) == 0)) {
164 // Card table is aligned so the lowest byte of the table address base is zero.
165 // This works only if the code is not saved for later use, possibly
166 // in a context where the base would no longer be aligned.
167 __ strb(card_table_base, card_table_addr);
168 } else {
169 __ mov(tmp, 0);
170 __ strb(tmp, card_table_addr);
171 }
172 }
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