Add x86-optimized versions of exponent_min().

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/libavcodec/ac3dsp.c b/libavcodec/ac3dsp.c
new file mode 100644
index 0000000000..f688e6a72b
--- /dev/null
+++ b/libavcodec/ac3dsp.c
@@ -0,0 +1,51 @@
+/*
+ * AC-3 DSP utils
+ * Copyright (c) 2011 Justin Ruggles
+ *
+ * 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 "avcodec.h"
+#include "ac3dsp.h"
+
+static void ac3_exponent_min_c(uint8_t *exp, int num_reuse_blocks, int nb_coefs)
+{
+    int blk, i;
+
+    if (!num_reuse_blocks)
+        return;
+
+    for (i = 0; i < nb_coefs; i++) {
+        uint8_t min_exp = *exp;
+        uint8_t *exp1 = exp + 256;
+        for (blk = 0; blk < num_reuse_blocks; blk++) {
+            uint8_t next_exp = *exp1;
+            if (next_exp < min_exp)
+                min_exp = next_exp;
+            exp1 += 256;
+        }
+        *exp++ = min_exp;
+    }
+}
+
+av_cold void ff_ac3dsp_init(AC3DSPContext *c)
+{
+    c->ac3_exponent_min = ac3_exponent_min_c;
+
+    if (HAVE_MMX)
+        ff_ac3dsp_init_x86(c);
+}