From 1c97fe3340fe806ca3e506cb430c2c6d76f439dd Mon Sep 17 00:00:00 2001
From: crueter <crueter@eden-emu.dev>
Date: Sat, 27 Sep 2025 07:59:24 +0200
Subject: [PATCH] [common] revert "replace Common::BitSet with std::bitset"

this commit appears to cause some games to not boot on certain platforms (Linux is unaffected)--needs testing since this may be a linker issue
---
 src/common/CMakeLists.txt              |  1 +
 src/common/bit_set.h                   | 86 ++++++++++++++++++++++++++
 src/core/hle/kernel/k_priority_queue.h | 29 ++++-----
 3 files changed, 98 insertions(+), 18 deletions(-)
 create mode 100644 src/common/bit_set.h

diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index 96ea429e5a..7759ea6a21 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -32,6 +32,7 @@ add_library(
   atomic_ops.h
   bit_cast.h
   bit_field.h
+  bit_set.h
   bit_util.h
   bounded_threadsafe_queue.h
   cityhash.cpp
diff --git a/src/common/bit_set.h b/src/common/bit_set.h
new file mode 100644
index 0000000000..74754504be
--- /dev/null
+++ b/src/common/bit_set.h
@@ -0,0 +1,86 @@
+// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <array>
+#include <bit>
+
+#include "common/alignment.h"
+#include "common/bit_util.h"
+#include "common/common_types.h"
+
+namespace Common {
+
+namespace impl {
+
+template <typename Storage, size_t N>
+class BitSet {
+
+public:
+    constexpr BitSet() = default;
+
+    constexpr void SetBit(size_t i) {
+        this->words[i / FlagsPerWord] |= GetBitMask(i % FlagsPerWord);
+    }
+
+    constexpr void ClearBit(size_t i) {
+        this->words[i / FlagsPerWord] &= ~GetBitMask(i % FlagsPerWord);
+    }
+
+    constexpr size_t CountLeadingZero() const {
+        for (size_t i = 0; i < NumWords; i++) {
+            if (this->words[i]) {
+                return FlagsPerWord * i + CountLeadingZeroImpl(this->words[i]);
+            }
+        }
+        return FlagsPerWord * NumWords;
+    }
+
+    constexpr size_t GetNextSet(size_t n) const {
+        for (size_t i = (n + 1) / FlagsPerWord; i < NumWords; i++) {
+            Storage word = this->words[i];
+            if (!IsAligned(n + 1, FlagsPerWord)) {
+                word &= GetBitMask(n % FlagsPerWord) - 1;
+            }
+            if (word) {
+                return FlagsPerWord * i + CountLeadingZeroImpl(word);
+            }
+        }
+        return FlagsPerWord * NumWords;
+    }
+
+private:
+    static_assert(std::is_unsigned_v<Storage>);
+    static_assert(sizeof(Storage) <= sizeof(u64));
+
+    static constexpr size_t FlagsPerWord = BitSize<Storage>();
+    static constexpr size_t NumWords = AlignUp(N, FlagsPerWord) / FlagsPerWord;
+
+    static constexpr auto CountLeadingZeroImpl(Storage word) {
+        return std::countl_zero(static_cast<unsigned long long>(word)) -
+               (BitSize<unsigned long long>() - FlagsPerWord);
+    }
+
+    static constexpr Storage GetBitMask(size_t bit) {
+        return Storage(1) << (FlagsPerWord - 1 - bit);
+    }
+
+    std::array<Storage, NumWords> words{};
+};
+
+} // namespace impl
+
+template <size_t N>
+using BitSet8 = impl::BitSet<u8, N>;
+
+template <size_t N>
+using BitSet16 = impl::BitSet<u16, N>;
+
+template <size_t N>
+using BitSet32 = impl::BitSet<u32, N>;
+
+template <size_t N>
+using BitSet64 = impl::BitSet<u64, N>;
+
+} // namespace Common
diff --git a/src/core/hle/kernel/k_priority_queue.h b/src/core/hle/kernel/k_priority_queue.h
index 0ef6bcc32c..26677ec65c 100644
--- a/src/core/hle/kernel/k_priority_queue.h
+++ b/src/core/hle/kernel/k_priority_queue.h
@@ -1,6 +1,3 @@
-// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
-// SPDX-License-Identifier: GPL-3.0-or-later
-
 // SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -8,11 +5,10 @@
 
 #include <array>
 #include <bit>
-#include <bitset>
 #include <concepts>
-#include <cstddef>
 
 #include "common/assert.h"
+#include "common/bit_set.h"
 #include "common/common_types.h"
 #include "common/concepts.h"
 
@@ -163,7 +159,7 @@ public:
             }
 
             if (m_queues[priority].PushBack(core, member)) {
-                m_available_priorities[core].set(std::size_t(priority));
+                m_available_priorities[core].SetBit(priority);
             }
         }
 
@@ -176,7 +172,7 @@ public:
             }
 
             if (m_queues[priority].PushFront(core, member)) {
-                m_available_priorities[core].set(std::size_t(priority));
+                m_available_priorities[core].SetBit(priority);
             }
         }
 
@@ -189,14 +185,14 @@ public:
             }
 
             if (m_queues[priority].Remove(core, member)) {
-                m_available_priorities[core].reset(std::size_t(priority));
+                m_available_priorities[core].ClearBit(priority);
             }
         }
 
         constexpr Member* GetFront(s32 core) const {
             ASSERT(IsValidCore(core));
 
-            const s32 priority = s32((~m_available_priorities[core]).count());
+            const s32 priority = static_cast<s32>(m_available_priorities[core].CountLeadingZero());
             if (priority <= LowestPriority) {
                 return m_queues[priority].GetFront(core);
             } else {
@@ -220,14 +216,11 @@ public:
 
             Member* next = member->GetPriorityQueueEntry(core).GetNext();
             if (next == nullptr) {
-                s32 priority = member->GetPriority() + 1;
-                do {
-                    if (m_available_priorities[core][priority]) {
-                        next = m_queues[priority].GetFront(core);
-                        break;
-                    }
-                    ++priority;
-                } while (priority <= LowestPriority && priority < s32(m_available_priorities[core].size()));
+                const s32 priority = static_cast<s32>(
+                    m_available_priorities[core].GetNextSet(member->GetPriority()));
+                if (priority <= LowestPriority) {
+                    next = m_queues[priority].GetFront(core);
+                }
             }
             return next;
         }
@@ -257,7 +250,7 @@ public:
 
     private:
         std::array<KPerCoreQueue, NumPriority> m_queues{};
-        std::array<std::bitset<NumPriority>, NumCores> m_available_priorities{};
+        std::array<Common::BitSet64<NumPriority>, NumCores> m_available_priorities{};
     };
 
 private: