HalfFloat_SSE2 port from C algorithm to SSE2

include/libyuv/row.h

 /*
  *  Copyright 2011 The LibYuv 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.
  */
 
@@ skipping 244 matching lines @@
 #define HAS_RGB565TOARGBROW_AVX2
 #endif
 
 // The following are also available on x64 Visual C.
 #if !defined(LIBYUV_DISABLE_X86) && defined(_MSC_VER) && defined(_M_X64) && \
     (!defined(__clang__) || defined(__SSSE3__))
 #define HAS_I422ALPHATOARGBROW_SSSE3
 #define HAS_I422TOARGBROW_SSSE3
 #endif
 
+// The following are available on gcc x86 platforms:
+// TODO(fbarchard): Port to Visual C.
+#if !defined(LIBYUV_DISABLE_X86) && \
+    (defined(__x86_64__) || (defined(__i386__) && !defined(_MSC_VER)))
+#define HAS_HALFFLOATROW_SSE2
+#endif
+
 // The following are available on Neon platforms:
 #if !defined(LIBYUV_DISABLE_NEON) && \
     (defined(__aarch64__) || defined(__ARM_NEON__) || defined(LIBYUV_NEON))
 #define HAS_ABGRTOUVROW_NEON
 #define HAS_ABGRTOYROW_NEON
 #define HAS_ARGB1555TOARGBROW_NEON
 #define HAS_ARGB1555TOUVROW_NEON
 #define HAS_ARGB1555TOYROW_NEON
 #define HAS_ARGB4444TOARGBROW_NEON
 #define HAS_ARGB4444TOUVROW_NEON
@@ skipping 1656 matching lines @@
                             int width);
 void ARGBPolynomialRow_AVX2(const uint8* src_argb,
                             uint8* dst_argb, const float* poly,
                             int width);
 
 // Scale and convert to half float.
 void HalfFloatRow_C(const uint16* src, uint16* dst, float scale, int width);
 void HalfFloatRow_AVX2(const uint16* src, uint16* dst, float scale, int width);
 void HalfFloatRow_Any_AVX2(const uint16* src, uint16* dst, float scale,
                            int width);
+void HalfFloatRow_SSE2(const uint16* src, uint16* dst, float scale, int width);
+void HalfFloatRow_Any_SSE2(const uint16* src, uint16* dst, float scale,
+                           int width);
 
 void ARGBLumaColorTableRow_C(const uint8* src_argb, uint8* dst_argb, int width,
                              const uint8* luma, uint32 lumacoeff);
 void ARGBLumaColorTableRow_SSSE3(const uint8* src_argb, uint8* dst_argb,
                                  int width,
                                  const uint8* luma, uint32 lumacoeff);
 
 #ifdef __cplusplus
 }  // extern "C"
 }  // namespace libyuv
 #endif
 
 #endif  // INCLUDE_LIBYUV_ROW_H_