From 7d9c338e2a100c6ddcbaa03d84c33661196bb717 Mon Sep 17 00:00:00 2001
From: Aiken Harris <harraiken91@gmail.com>
Date: Mon, 29 Jun 2026 00:31:55 +0200
Subject: [PATCH] Provide atomic bit test and clear functionality

---
 xtoskrnl/includes/rtl/atomic.hh |  4 +++
 xtoskrnl/rtl/atomic.cc          | 46 +++++++++++++++++++++++++++++++--
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/xtoskrnl/includes/rtl/atomic.hh b/xtoskrnl/includes/rtl/atomic.hh
index 1501795..1325bf5 100644
--- a/xtoskrnl/includes/rtl/atomic.hh
+++ b/xtoskrnl/includes/rtl/atomic.hh
@@ -36,6 +36,10 @@ namespace RTL
                                          IN LONG Mask);
             STATIC XTFASTCALL LONG_PTR And64(IN PLONG_PTR Address,
                                              IN LONG_PTR Mask);
+            STATIC XTFASTCALL UCHAR BitTestAndReset(IN PLONG Base,
+                                                    IN LONG Offset);
+            STATIC XTFASTCALL UCHAR BitTestAndReset64(IN PLONGLONG Base,
+                                                      IN LONGLONG Offset);
             STATIC XTFASTCALL UCHAR BitTestAndSet(IN PLONG Base,
                                                   IN LONG Offset);
             STATIC XTFASTCALL UCHAR BitTestAndSet64(IN PLONGLONG Base,
diff --git a/xtoskrnl/rtl/atomic.cc b/xtoskrnl/rtl/atomic.cc
index 4d75041..a115ef1 100644
--- a/xtoskrnl/rtl/atomic.cc
+++ b/xtoskrnl/rtl/atomic.cc
@@ -199,6 +199,48 @@ RTL::Atomic::And64(IN PLONG_PTR Address,
     return __sync_fetch_and_and(Address, Mask);
 }
 
+/**
+ * Performs an atomic test of the specified bit of the specified long value and resets it to 0.
+ *
+ * @param Base
+ *        Supplies a pointer to the variable.
+ *
+ * @param Offset
+ *        Specifies the bit position to be tested.
+ *
+ * @return This routine returns the original value of the specified bit.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+UCHAR
+RTL::Atomic::BitTestAndReset(IN PLONG Base,
+                             IN LONG Offset)
+{
+    return (__atomic_fetch_and(Base, ~(1l << Offset), __ATOMIC_SEQ_CST) >> Offset) & 1;
+}
+
+/**
+ * Performs an atomic test of the specified bit of the specified 64-bit long value and resets it to 0.
+ *
+ * @param Base
+ *        Supplies a pointer to the variable.
+ *
+ * @param Offset
+ *        Specifies the bit position to be tested.
+ *
+ * @return This routine returns the original value of the specified bit.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+UCHAR
+RTL::Atomic::BitTestAndReset64(IN PLONGLONG Base,
+                               IN LONGLONG Offset)
+{
+    return (__atomic_fetch_and(Base, ~(1ll << Offset), __ATOMIC_SEQ_CST) >> Offset) & 1;
+}
+
 /**
  * Performs an atomic test of the specified bit of the specified long value and sets it to 1.
  *
@@ -208,7 +250,7 @@ RTL::Atomic::And64(IN PLONG_PTR Address,
  * @param Offset
  *        Specifies the bit position to be tested.
  *
- * @return Returns a value of the specified bit.
+ * @return This routine returns a value of the specified bit.
  *
  * @since XT 1.0
  */
@@ -229,7 +271,7 @@ RTL::Atomic::BitTestAndSet(IN PLONG Base,
  * @param Offset
  *        Specifies the bit position to be tested.
  *
- * @return Returns a value of the specified bit.
+ * @return This routine returns a value of the specified bit.
  *
  * @since XT 1.0
  */