From 1f8026db2fdd3fb54e5ed335789796c247bf1994 Mon Sep 17 00:00:00 2001
From: belliash <belliash@codingworkshop.eu.org>
Date: Fri, 17 Mar 2023 18:06:53 +0100
Subject: [PATCH] Implement RtlInterlockedCompareExchangePointer() and
 RtlInterlockedDecrementLongPtr() atomic routines

---
 sdk/xtdk/rtlfuncs.h     | 10 ++++++++
 xtoskrnl/CMakeLists.txt |  1 +
 xtoskrnl/rtl/intrin.c   | 52 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+)
 create mode 100644 xtoskrnl/rtl/intrin.c

diff --git a/sdk/xtdk/rtlfuncs.h b/sdk/xtdk/rtlfuncs.h
index cc476ac..7b957dd 100644
--- a/sdk/xtdk/rtlfuncs.h
+++ b/sdk/xtdk/rtlfuncs.h
@@ -230,6 +230,16 @@ VOID
 RtlInsertTailList(IN OUT PLIST_ENTRY ListHead,
                   IN PLIST_ENTRY Entry);
 
+XTFASTCALL
+PVOID
+RtlInterlockedCompareExchangePointer(IN VOLATILE PVOID *Destination,
+                                     IN PVOID Comperand,
+                                     IN PVOID Exchange);
+
+XTFASTCALL
+LONG_PTR
+RtlInterlockedDecrementLongPtr(IN VOLATILE PLONG_PTR Addend);
+
 XTCDECL
 BOOLEAN
 RtlListEmpty(PLIST_ENTRY ListHead);
diff --git a/xtoskrnl/CMakeLists.txt b/xtoskrnl/CMakeLists.txt
index fcde6c9..7e7bef9 100644
--- a/xtoskrnl/CMakeLists.txt
+++ b/xtoskrnl/CMakeLists.txt
@@ -34,6 +34,7 @@ list(APPEND XTOSKRNL_SOURCE
     ${XTOSKRNL_SOURCE_DIR}/po/idle.c
     ${XTOSKRNL_SOURCE_DIR}/rtl/atomic.c
     ${XTOSKRNL_SOURCE_DIR}/rtl/byteswap.c
+    ${XTOSKRNL_SOURCE_DIR}/rtl/intrin.c
     ${XTOSKRNL_SOURCE_DIR}/rtl/memory.c
     ${XTOSKRNL_SOURCE_DIR}/rtl/plist.c
     ${XTOSKRNL_SOURCE_DIR}/rtl/string.c
diff --git a/xtoskrnl/rtl/intrin.c b/xtoskrnl/rtl/intrin.c
new file mode 100644
index 0000000..4b9df3c
--- /dev/null
+++ b/xtoskrnl/rtl/intrin.c
@@ -0,0 +1,52 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/rtl/intrin.c
+ * DESCRIPTION:     Interlocked operations support
+ * DEVELOPERS:      Rafal Kupiec <belliash@codingworkshop.eu.org>
+ */
+
+#include <xtos.h>
+
+
+/**
+ * Performs an atomic compare exchange operation on the pointer value.
+ *
+ * @param Destination
+ *        Supplues a pointer to the variable for the compare exchange operation.
+ *
+ * @param Comperand
+ *        Supplies a pointer value used in compare operation.
+ *
+ * @param Exchange
+ *        Supplies a pointer value used in exchange operation.
+ *
+ * @return This routine returns the initial pointer value of the Destination parameter.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+PVOID
+RtlInterlockedCompareExchangePointer(IN VOLATILE PVOID *Destination,
+                                     IN PVOID Comperand,
+                                     IN PVOID Exchange)
+{
+    return (PVOID)__sync_val_compare_and_swap(Destination, Comperand, Exchange);
+}
+
+/**
+ * Performs an atomic decrement of the 32-bit or 64bit value, depending on architecture.
+ *
+ * @param Addend
+ *        Specifies a pointer to the variable to be decremented.
+ *
+ * @return This routine returns the decremented value.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+LONG_PTR
+RtlInterlockedDecrementLongPtr(IN VOLATILE PLONG_PTR Addend)
+{
+    return (LONG_PTR)__sync_sub_and_fetch(Addend, 1);
+}