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https://github.com/Atmosphere-NX/Atmosphere.git
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bfffe6b119
This is an optimization that saves the most common type of virtual call in the kernel (DynamicCast) by storing class token as a member, rather than getting it via virtual call every time. This does not currently cost any memory space on 64-bit targets, due to pre-existing padding space. This optimization can be turned off via a compile-time flag for accuracy.
61 lines
2.1 KiB
C++
61 lines
2.1 KiB
C++
/*
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* Copyright (c) Atmosphère-NX
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <mesosphere.hpp>
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namespace ams::kern {
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KAutoObject *KAutoObject::Create(KAutoObject *obj) {
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obj->m_ref_count = 1;
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#if defined(MESOSPHERE_ENABLE_DEVIRTUALIZED_DYNAMIC_CAST)
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obj->m_class_token = obj->GetTypeObj().GetClassToken();
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#endif
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return obj;
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}
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NOINLINE bool KAutoObject::Open() {
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MESOSPHERE_ASSERT_THIS();
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/* Atomically increment the reference count, only if it's positive. */
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u32 cur_ref_count = m_ref_count.load(std::memory_order_relaxed);
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do {
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if (AMS_UNLIKELY(cur_ref_count == 0)) {
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MESOSPHERE_AUDIT(cur_ref_count != 0);
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return false;
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}
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MESOSPHERE_ABORT_UNLESS(cur_ref_count < cur_ref_count + 1);
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} while (!m_ref_count.compare_exchange_weak(cur_ref_count, cur_ref_count + 1, std::memory_order_relaxed));
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return true;
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}
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NOINLINE void KAutoObject::Close() {
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MESOSPHERE_ASSERT_THIS();
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/* Atomically decrement the reference count, not allowing it to become negative. */
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u32 cur_ref_count = m_ref_count.load(std::memory_order_relaxed);
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do {
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MESOSPHERE_ABORT_UNLESS(cur_ref_count > 0);
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} while (!m_ref_count.compare_exchange_weak(cur_ref_count, cur_ref_count - 1, std::memory_order_relaxed));
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/* If ref count hits zero, schedule the object for destruction. */
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if (cur_ref_count - 1 == 0) {
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this->ScheduleDestruction();
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}
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}
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}
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