avcodec/mips: MSA (MIPS-SIMD-Arch) optimizations for pixblock functions

This patch adds MSA (MIPS-SIMD-Arch) optimizations for pixblock functions in new file pixblockdsp_msa.c
Adds new generic macros (needed for this patch) in libavutil/mips/generic_macros_msa.h

Signed-off-by: Shivraj Patil <shivraj.patil@imgtec.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mips/pixblockdsp_init_mips.c

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2015 Shivraj Patil (Shivraj.Patil@imgtec.com)
+ *
+ * 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
+ */
+
+#include "pixblockdsp_mips.h"
+
+#if HAVE_MSA
+static av_cold void pixblockdsp_init_msa(PixblockDSPContext *c,
+                                         AVCodecContext *avctx,
+                                         unsigned high_bit_depth)
+{
+    c->diff_pixels = ff_diff_pixels_msa;
+
+    switch (avctx->bits_per_raw_sample) {
+    case 9:
+    case 10:
+    case 12:
+    case 14:
+        c->get_pixels = ff_get_pixels_16_msa;
+        break;
+    default:
+        if (avctx->bits_per_raw_sample <= 8 || avctx->codec_type !=
+            AVMEDIA_TYPE_VIDEO) {
+            c->get_pixels = ff_get_pixels_8_msa;
+        }
+        break;
+    }
+}
+#endif  // #if HAVE_MSA
+
+void ff_pixblockdsp_init_mips(PixblockDSPContext *c, AVCodecContext *avctx,
+                              unsigned high_bit_depth)
+{
+#if HAVE_MSA
+    pixblockdsp_init_msa(c, avctx, high_bit_depth);
+#endif  // #if HAVE_MSA
+}