2663
2664 // Get the handle (the 2nd argument)
2665 __ mov(oop_handle_reg, c_rarg1);
2666
2667 // Get address of the box
2668
2669 __ lea(lock_reg, Address(rsp, lock_slot_offset * VMRegImpl::stack_slot_size));
2670
2671 // Load the oop from the handle
2672 __ movptr(obj_reg, Address(oop_handle_reg, 0));
2673
2674 if (UseBiasedLocking) {
2675 __ biased_locking_enter(lock_reg, obj_reg, swap_reg, rscratch1, false, lock_done, &slow_path_lock);
2676 }
2677
2678 // Load immediate 1 into swap_reg %rax
2679 __ movl(swap_reg, 1);
2680
2681 // Load (object->mark() | 1) into swap_reg %rax
2682 __ orptr(swap_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
2683
2684 // Save (object->mark() | 1) into BasicLock's displaced header
2685 __ movptr(Address(lock_reg, mark_word_offset), swap_reg);
2686
2687 if (os::is_MP()) {
2688 __ lock();
2689 }
2690
2691 // src -> dest iff dest == rax else rax <- dest
2692 __ cmpxchgptr(lock_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
2693 __ jcc(Assembler::equal, lock_done);
2694
2695 // Hmm should this move to the slow path code area???
2696
2697 // Test if the oopMark is an obvious stack pointer, i.e.,
2698 // 1) (mark & 3) == 0, and
2699 // 2) rsp <= mark < mark + os::pagesize()
2700 // These 3 tests can be done by evaluating the following
2701 // expression: ((mark - rsp) & (3 - os::vm_page_size())),
2702 // assuming both stack pointer and pagesize have their
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2663
2664 // Get the handle (the 2nd argument)
2665 __ mov(oop_handle_reg, c_rarg1);
2666
2667 // Get address of the box
2668
2669 __ lea(lock_reg, Address(rsp, lock_slot_offset * VMRegImpl::stack_slot_size));
2670
2671 // Load the oop from the handle
2672 __ movptr(obj_reg, Address(oop_handle_reg, 0));
2673
2674 if (UseBiasedLocking) {
2675 __ biased_locking_enter(lock_reg, obj_reg, swap_reg, rscratch1, false, lock_done, &slow_path_lock);
2676 }
2677
2678 // Load immediate 1 into swap_reg %rax
2679 __ movl(swap_reg, 1);
2680
2681 // Load (object->mark() | 1) into swap_reg %rax
2682 __ orptr(swap_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
2683 if (EnableValhalla && !UseBiasedLocking) {
2684 // For slow path is_always_locked, using biased, which is never natural for !UseBiasLocking
2685 __ andptr(swap_reg, ~markOopDesc::biased_lock_bit_in_place);
2686 }
2687
2688 // Save (object->mark() | 1) into BasicLock's displaced header
2689 __ movptr(Address(lock_reg, mark_word_offset), swap_reg);
2690
2691 if (os::is_MP()) {
2692 __ lock();
2693 }
2694
2695 // src -> dest iff dest == rax else rax <- dest
2696 __ cmpxchgptr(lock_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
2697 __ jcc(Assembler::equal, lock_done);
2698
2699 // Hmm should this move to the slow path code area???
2700
2701 // Test if the oopMark is an obvious stack pointer, i.e.,
2702 // 1) (mark & 3) == 0, and
2703 // 2) rsp <= mark < mark + os::pagesize()
2704 // These 3 tests can be done by evaluating the following
2705 // expression: ((mark - rsp) & (3 - os::vm_page_size())),
2706 // assuming both stack pointer and pagesize have their
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