ac3enc: add SIMD-optimized shifting functions for use with the fixed-point AC3 encoder.

1 files changed, 37 insertions, 0 deletions

diff --git a/libavcodec/ac3dsp.c b/libavcodec/ac3dsp.c
index da3a123e9b..4d9db9be50 100644
--- a/libavcodec/ac3dsp.c
+++ b/libavcodec/ac3dsp.c
@@ -50,10 +50,47 @@ static int ac3_max_msb_abs_int16_c(const int16_t *src, int len)
     return v;
 }
 
+static void ac3_lshift_int16_c(int16_t *src, unsigned int len,
+                               unsigned int shift)
+{
+    uint32_t *src32 = (uint32_t *)src;
+    const uint32_t mask = ~(((1 << shift) - 1) << 16);
+    int i;
+    len >>= 1;
+    for (i = 0; i < len; i += 8) {
+        src32[i  ] = (src32[i  ] << shift) & mask;
+        src32[i+1] = (src32[i+1] << shift) & mask;
+        src32[i+2] = (src32[i+2] << shift) & mask;
+        src32[i+3] = (src32[i+3] << shift) & mask;
+        src32[i+4] = (src32[i+4] << shift) & mask;
+        src32[i+5] = (src32[i+5] << shift) & mask;
+        src32[i+6] = (src32[i+6] << shift) & mask;
+        src32[i+7] = (src32[i+7] << shift) & mask;
+    }
+}
+
+static void ac3_rshift_int32_c(int32_t *src, unsigned int len,
+                               unsigned int shift)
+{
+    do {
+        *src++ >>= shift;
+        *src++ >>= shift;
+        *src++ >>= shift;
+        *src++ >>= shift;
+        *src++ >>= shift;
+        *src++ >>= shift;
+        *src++ >>= shift;
+        *src++ >>= shift;
+        len -= 8;
+    } while (len > 0);
+}
+
 av_cold void ff_ac3dsp_init(AC3DSPContext *c)
 {
     c->ac3_exponent_min = ac3_exponent_min_c;
     c->ac3_max_msb_abs_int16 = ac3_max_msb_abs_int16_c;
+    c->ac3_lshift_int16 = ac3_lshift_int16_c;
+    c->ac3_rshift_int32 = ac3_rshift_int32_c;
 
     if (HAVE_MMX)
         ff_ac3dsp_init_x86(c);