--- old/src/cpu/aarch64/vm/c1_Runtime1_aarch64.cpp	2016-01-11 15:10:31.694904000 +0000
+++ new/src/cpu/aarch64/vm/c1_Runtime1_aarch64.cpp	2016-01-11 15:10:31.434904000 +0000
@@ -1148,9 +1148,6 @@
 
 #if INCLUDE_ALL_GCS
 
-// Registers to be saved around calls to g1_wb_pre or g1_wb_post
-#define G1_SAVE_REGS (RegSet::range(r0, r18) - RegSet::of(rscratch1, rscratch2))
-
     case g1_pre_barrier_slow_id:
       {
         StubFrame f(sasm, "g1_pre_barrier", dont_gc_arguments);
@@ -1192,10 +1189,10 @@
         __ b(done);
 
         __ bind(runtime);
-        __ push(G1_SAVE_REGS, sp);
+        __ push_call_clobbered_registers();
         f.load_argument(0, pre_val);
         __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), pre_val, thread);
-        __ pop(G1_SAVE_REGS, sp);
+        __ pop_call_clobbered_registers();
         __ bind(done);
       }
       break;
@@ -1223,45 +1220,49 @@
         Address buffer(thread, in_bytes(JavaThread::dirty_card_queue_offset() +
                                         DirtyCardQueue::byte_offset_of_buf()));
 
-        const Register card_addr = rscratch2;
-        ExternalAddress cardtable((address) ct->byte_map_base);
-
-        f.load_argument(0, card_addr);
-        __ lsr(card_addr, card_addr, CardTableModRefBS::card_shift);
-        unsigned long offset;
-        __ adrp(rscratch1, cardtable, offset);
-        __ add(card_addr, card_addr, rscratch1);
-        __ ldrb(rscratch1, Address(card_addr, offset));
+        const Register card_offset = rscratch2;
+        // LR is free here, so we can use it to hold the byte_map_base.
+        const Register byte_map_base = lr;
+
+        assert_different_registers(card_offset, byte_map_base, rscratch1);
+
+        f.load_argument(0, card_offset);
+        __ lsr(card_offset, card_offset, CardTableModRefBS::card_shift);
+        __ load_byte_map_base(byte_map_base);
+        __ ldrb(rscratch1, Address(byte_map_base, card_offset));
         __ cmpw(rscratch1, (int)G1SATBCardTableModRefBS::g1_young_card_val());
         __ br(Assembler::EQ, done);
 
         assert((int)CardTableModRefBS::dirty_card_val() == 0, "must be 0");
 
         __ membar(Assembler::StoreLoad);
-        __ ldrb(rscratch1, Address(card_addr, offset));
+        __ ldrb(rscratch1, Address(byte_map_base, card_offset));
         __ cbzw(rscratch1, done);
 
         // storing region crossing non-NULL, card is clean.
         // dirty card and log.
-        __ strb(zr, Address(card_addr, offset));
+        __ strb(zr, Address(byte_map_base, card_offset));
+
+        // Convert card offset into an address in card_addr
+        Register card_addr = card_offset;
+        __ add(card_addr, byte_map_base, card_addr);
 
         __ ldr(rscratch1, queue_index);
         __ cbz(rscratch1, runtime);
         __ sub(rscratch1, rscratch1, wordSize);
         __ str(rscratch1, queue_index);
 
-        const Register buffer_addr = r0;
+        // Reuse LR to hold buffer_addr
+        const Register buffer_addr = lr;
 
-        __ push(RegSet::of(r0, r1), sp);
         __ ldr(buffer_addr, buffer);
         __ str(card_addr, Address(buffer_addr, rscratch1));
-        __ pop(RegSet::of(r0, r1), sp);
         __ b(done);
 
         __ bind(runtime);
-        __ push(G1_SAVE_REGS, sp);
+        __ push_call_clobbered_registers();
         __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), card_addr, thread);
-        __ pop(G1_SAVE_REGS, sp);
+        __ pop_call_clobbered_registers();
         __ bind(done);
 
       }