From 60beb781c140b61c1957abd2a6717d2e9a831933 Mon Sep 17 00:00:00 2001
From: Johann Koenig <johannkoenig@google.com>
Date: Wed, 14 Mar 2018 19:06:57 +0000
Subject: [PATCH] Revert "use intrinsics for 'emms'"

This reverts commit 118a57045bf5b49ab7c2f7f930543b9217fd422e.

Reason for revert: Fails on Visual Studio builds:

vpxmdd.lib(vpx_ports_emms_mmx.obj) : error LNK2019: unresolved
external symbol _m_empty referenced in function
vpx_clear_system_state

Original change's description:
> use intrinsics for 'emms'
>
> BUG=webm:1500
>
> Change-Id: I3235d8c2abc01dd3a35e14c5cbcfe20283ff8fb2

Change-Id: Ia9c40bc103c57cced83353249c55218eaf2f0b0c
---
 test/clear_system_state.h | 10 ++++++++--
 vpx_ports/emms.asm        |  5 +++++
 vpx_ports/emms_mmx.c      | 13 -------------
 vpx_ports/system_state.h  | 16 ++++------------
 vpx_ports/vpx_ports.mk    |  2 --
 vpx_ports/x86.h           |  2 ++
 6 files changed, 19 insertions(+), 29 deletions(-)
 delete mode 100644 vpx_ports/emms_mmx.c

diff --git a/test/clear_system_state.h b/test/clear_system_state.h
index 609a8b050..044a5c758 100644
--- a/test/clear_system_state.h
+++ b/test/clear_system_state.h
@@ -11,13 +11,19 @@
 #define TEST_CLEAR_SYSTEM_STATE_H_
 
 #include "./vpx_config.h"
-#include "vpx_ports/system_state.h"
+#if ARCH_X86 || ARCH_X86_64
+#include "vpx_ports/x86.h"
+#endif
 
 namespace libvpx_test {
 
 // Reset system to a known state. This function should be used for all non-API
 // test cases.
-inline void ClearSystemState() { vpx_clear_system_state(); }
+inline void ClearSystemState() {
+#if ARCH_X86 || ARCH_X86_64
+  vpx_reset_mmx_state();
+#endif
+}
 
 }  // namespace libvpx_test
 #endif  // TEST_CLEAR_SYSTEM_STATE_H_
diff --git a/vpx_ports/emms.asm b/vpx_ports/emms.asm
index 256dae084..db8da2873 100644
--- a/vpx_ports/emms.asm
+++ b/vpx_ports/emms.asm
@@ -12,6 +12,11 @@
 %include "vpx_ports/x86_abi_support.asm"
 
 section .text
+global sym(vpx_reset_mmx_state) PRIVATE
+sym(vpx_reset_mmx_state):
+    emms
+    ret
+
 
 %if LIBVPX_YASM_WIN64
 global sym(vpx_winx64_fldcw) PRIVATE
diff --git a/vpx_ports/emms_mmx.c b/vpx_ports/emms_mmx.c
deleted file mode 100644
index 1b28809a3..000000000
--- a/vpx_ports/emms_mmx.c
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- *  Copyright (c) 2018 The WebM project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include <mmintrin.h>
-
-void vpx_clear_system_state() { _mm_empty(); }
diff --git a/vpx_ports/system_state.h b/vpx_ports/system_state.h
index d1efb0df4..086c64681 100644
--- a/vpx_ports/system_state.h
+++ b/vpx_ports/system_state.h
@@ -13,18 +13,10 @@
 
 #include "./vpx_config.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#if HAVE_MMX
-extern void vpx_clear_system_state();
+#if ARCH_X86 || ARCH_X86_64
+void vpx_reset_mmx_state(void);
+#define vpx_clear_system_state() vpx_reset_mmx_state()
 #else
 #define vpx_clear_system_state()
-#endif  // HAVE_MMX
-
-#ifdef __cplusplus
-}  // extern "C"
-#endif
-
+#endif  // ARCH_X86 || ARCH_X86_64
 #endif  // VPX_PORTS_SYSTEM_STATE_H_
diff --git a/vpx_ports/vpx_ports.mk b/vpx_ports/vpx_ports.mk
index 5d416cf09..e17145e6c 100644
--- a/vpx_ports/vpx_ports.mk
+++ b/vpx_ports/vpx_ports.mk
@@ -17,8 +17,6 @@ PORTS_SRCS-yes += msvc.h
 PORTS_SRCS-yes += system_state.h
 PORTS_SRCS-yes += vpx_timer.h
 
-PORTS_SRCS-$(HAVE_MMX) += emms_mmx.c
-
 ifeq ($(ARCH_X86)$(ARCH_X86_64),yes)
 PORTS_SRCS-yes += emms.asm
 PORTS_SRCS-yes += x86.h
diff --git a/vpx_ports/x86.h b/vpx_ports/x86.h
index 60c625778..ced65ac05 100644
--- a/vpx_ports/x86.h
+++ b/vpx_ports/x86.h
@@ -317,6 +317,8 @@ static INLINE unsigned int x87_set_double_precision(void) {
   return mode;
 }
 
+extern void vpx_reset_mmx_state(void);
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif