From c76643021efdbd24b674298f802ff2c8d9316fe5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin@martin.st>
Date: Fri, 26 May 2023 14:05:30 +0300
Subject: [PATCH] aarch64: Add Windows runtime detection of the dotprod
 instructions
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For Windows, there's no publicly defined constant for checking for
the i8mm extension yet.

Signed-off-by: Martin Storsjö <martin@martin.st>
---
 libavutil/aarch64/cpu.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/libavutil/aarch64/cpu.c b/libavutil/aarch64/cpu.c
index b808a7650e..a8cb301dd7 100644
--- a/libavutil/aarch64/cpu.c
+++ b/libavutil/aarch64/cpu.c
@@ -83,6 +83,18 @@ static int detect_flags(void)
     return flags;
 }
 
+#elif defined(_WIN32)
+#include <windows.h>
+
+static int detect_flags(void)
+{
+    int flags = 0;
+#ifdef PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE
+    if (IsProcessorFeaturePresent(PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE))
+        flags |= AV_CPU_FLAG_DOTPROD;
+#endif
+    return flags;
+}
 #else
 
 static int detect_flags(void)