SDL: atomic: Use acquire/release InterlockedExchange intrinsics on ARM64EC (15275)

SDL Commits
1 
From 15275898f066c5bee802e0f8fb2a6e306d5a8496 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <[EMAIL REDACTED]>
Date: Fri, 24 Apr 2026 19:07:17 -0500
Subject: [PATCH] atomic: Use acquire/release InterlockedExchange intrinsics on
 ARM64EC

---
 src/atomic/SDL_spinlock.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/atomic/SDL_spinlock.c b/src/atomic/SDL_spinlock.c
index 3e439ce1c327b..3f58d26554a36 100644
--- a/src/atomic/SDL_spinlock.c
+++ b/src/atomic/SDL_spinlock.c
@@ -84,7 +84,7 @@ SDL_bool SDL_AtomicTryLock(SDL_SpinLock *lock)
 #elif defined(HAVE_GCC_ATOMICS) || defined(HAVE_GCC_SYNC_LOCK_TEST_AND_SET)
     return __sync_lock_test_and_set(lock, 1) == 0;
 
-#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64))
+#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64) || defined(_M_ARM64EC))
     return _InterlockedExchange_acq(lock, 1) == 0;
 
 #elif defined(_MSC_VER)
@@ -189,7 +189,7 @@ void SDL_AtomicUnlock(SDL_SpinLock *lock)
 #if defined(HAVE_GCC_ATOMICS) || defined(HAVE_GCC_SYNC_LOCK_TEST_AND_SET)
     __sync_lock_release(lock);
 
-#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64))
+#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64) || defined(_M_ARM64EC))
     _InterlockedExchange_rel(lock, 0);
 
 #elif defined(_MSC_VER)