import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

media/ffvpx/libavutil/x86/emms.h

@@ -0,0 +1,53 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_X86_EMMS_H
+#define AVUTIL_X86_EMMS_H
+
+#include "config.h"
+#include "libavutil/attributes.h"
+#include "libavutil/cpu.h"
+
+void avpriv_emms_yasm(void);
+
+#if HAVE_MMX_INLINE
+#   define emms_c emms_c
+/**
+ * Empty mmx state.
+ * this must be called between any dsp function and float/double code.
+ * for example sin(); dsp->idct_put(); emms_c(); cos()
+ */
+static av_always_inline void emms_c(void)
+{
+/* Some inlined functions may also use mmx instructions regardless of
+ * runtime cpuflags. With that in mind, we unconditionally empty the
+ * mmx state if the target cpu chosen at configure time supports it.
+ */
+#if !defined(__MMX__)
+    if(av_get_cpu_flags() & AV_CPU_FLAG_MMX)
+#endif
+        __asm__ volatile ("emms" ::: "memory");
+}
+#elif HAVE_MMX && HAVE_MM_EMPTY
+#   include <mmintrin.h>
+#   define emms_c _mm_empty
+#elif HAVE_MMX_EXTERNAL
+#   define emms_c avpriv_emms_yasm
+#endif /* HAVE_MMX_INLINE */
+
+#endif /* AVUTIL_X86_EMMS_H */