libvpx: Pull from upstream

source/libvpx/vp9/common/vp9_systemdependent.h

-/*
- *  Copyright (c) 2010 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.
- */
-
-#ifndef VP9_COMMON_VP9_SYSTEMDEPENDENT_H_
-#define VP9_COMMON_VP9_SYSTEMDEPENDENT_H_
-
-#include "vpx_ports/msvc.h"
-
-#ifdef _MSC_VER
-# include <math.h>  // the ceil() definition must precede intrin.h
-# if _MSC_VER > 1310 && (defined(_M_X64) || defined(_M_IX86))
-#  include <intrin.h>
-#  define USE_MSC_INTRINSICS
-# endif
-#endif
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#include "./vpx_config.h"
-#if ARCH_X86 || ARCH_X86_64
-void vpx_reset_mmx_state(void);
-#define vp9_clear_system_state() vpx_reset_mmx_state()
-#else
-#define vp9_clear_system_state()
-#endif
-
-#if defined(_MSC_VER) && _MSC_VER < 1800
-// round is not defined in MSVC before VS2013.
-static INLINE int round(double x) {
-  if (x < 0)
-    return (int)ceil(x - 0.5);
-  else
-    return (int)floor(x + 0.5);
-}
-#endif
-
-// use GNU builtins where available.
-#if defined(__GNUC__) && \
-    ((__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || __GNUC__ >= 4)
-static INLINE int get_msb(unsigned int n) {
-  return 31 ^ __builtin_clz(n);
-}
-#elif defined(USE_MSC_INTRINSICS)
-#pragma intrinsic(_BitScanReverse)
-
-static INLINE int get_msb(unsigned int n) {
-  unsigned long first_set_bit;
-  _BitScanReverse(&first_set_bit, n);
-  return first_set_bit;
-}
-#undef USE_MSC_INTRINSICS
-#else
-// Returns (int)floor(log2(n)). n must be > 0.
-static INLINE int get_msb(unsigned int n) {
-  int log = 0;
-  unsigned int value = n;
-  int i;
-
-  for (i = 4; i >= 0; --i) {
-    const int shift = (1 << i);
-    const unsigned int x = value >> shift;
-    if (x != 0) {
-      value = x;
-      log += shift;
-    }
-  }
-  return log;
-}
-#endif
-
-#ifdef __cplusplus
-}  // extern "C"
-#endif
-
-#endif  // VP9_COMMON_VP9_SYSTEMDEPENDENT_H_