Provide atomic pointer support.

This is initially used for TLS to make loading the engine pointer
faster, eliminating a much more expensive lock operation.

2 files changed, 17 insertions, 1 deletions

diff --git a/src/platform/windows/win_impl.h b/src/platform/windows/win_impl.h
index de4f8e5b..608a065e 100644
--- a/src/platform/windows/win_impl.h
+++ b/src/platform/windows/win_impl.h
@@ -1,5 +1,5 @@
 //
-// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2021 Staysail Systems, Inc. <info@staysail.tech>
 // Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
@@ -67,6 +67,10 @@ struct nni_atomic_u64 {
 	LONGLONG v;
 };
 
+struct nni_atomic_ptr {
+	LONGLONG v;
+};
+
 // nni_win_io is used with io completion ports.  This allows us to get
 // to a specific completion callback without requiring the poller (in the
 // completion port) to know anything about the event itself.
diff --git a/src/platform/windows/win_thread.c b/src/platform/windows/win_thread.c
index 9c7c09d3..31e783a3 100644
--- a/src/platform/windows/win_thread.c
+++ b/src/platform/windows/win_thread.c
@@ -223,6 +223,18 @@ nni_atomic_set64(nni_atomic_u64 *v, uint64_t u)
 	(void) InterlockedExchange64(&v->v, (LONGLONG) u);
 }
 
+void *
+nni_atomic_get_ptr(nni_atomic_ptr *v)
+{
+	return ((void *) (InterlockedExchangeAdd64(&v->v, 0)));
+}
+
+void
+nni_atomic_set_ptr(nni_atomic_ptr *v)
+{
+	(void) InterlockedExchange64(&v->v, (LONGLONG) (uintptr_t) v);
+}
+
 uint64_t
 nni_atomic_swap64(nni_atomic_u64 *v, uint64_t u)
 {