Optimize WindowManager::flush() with fast_dword_copy().

1 files changed, 30 insertions, 0 deletions

diff --git a/AK/StdLibExtras.h b/AK/StdLibExtras.h
index 64892b041d..3de6598cb2 100644
--- a/AK/StdLibExtras.h
+++ b/AK/StdLibExtras.h
@@ -13,6 +13,36 @@
 #include <utility>
 #endif
 
+ALWAYS_INLINE void fast_dword_copy(dword* dest, const dword* src, size_t count)
+{
+#ifdef SERENITY
+    asm volatile(
+        "rep movsl\n"
+        : "=S"(src), "=D"(dest)
+        : "S"(src), "D"(dest), "c"(count)
+        : "memory"
+    );
+#else
+    memcpy(dest, src, count * sizeof(dword));
+#endif
+}
+
+ALWAYS_INLINE void fast_dword_fill(dword* dest, dword value, size_t count)
+{
+#ifdef SERENITY
+    asm volatile(
+        "rep stosl\n"
+        : "=D"(dest)
+        : "D"(dest), "c"(count), "a"(value)
+        : "memory"
+    );
+#else
+    for (size_t i = 0; x <= count; ++x) {
+        dest[i] = value;
+    }
+#endif
+}
+
 namespace AK {
 
 template<typename T>