Abramo Bagnara <abramo@alsa-project.org>

Thu, 09 Dec 1999 09:56:47 +0100
Rate plugin is now ready for optimizations (I've verified reading asm
generated that loop unrolling is not fully satisfactory, I'll try
another solution later today).

diff --git a/src/pcm/plugin/rate.c b/src/pcm/plugin/rate.c
index 85814d7..ed38bf1 100644 (file)
--- a/src/pcm/plugin/rate.c
+++ b/src/pcm/plugin/rate.c
@@ -56,38 +56,42 @@ static void mix(struct rate_private_data *data, int voices,
 {
        unsigned int pos;
        signed int val;
-       signed short *S1, *S2;
+       signed short S1, S2;
        int voice;
+       signed short *src, *dst;
+       int size;
        
-       pos = data->pos;
-       S1 = data->last_S1;
-       S2 = data->last_S2;
-       if (pos >> SHIFT) {
-               src_ptr += ((pos >> SHIFT) - 1) * voices; pos &= MASK;
-               for (voice = 0; voice < voices; ++voice) {
-                       S1[voice] = S2[voice];
-                       S2[voice] = src_ptr[voice];
-               }
-       }
-       while (dst_size-- > 0) {
+       for (voice = 0; voice < voices; ++voice) {
+               pos = data->pos;
+               S1 = data->last_S1[voice];
+               S2 = data->last_S2[voice];
+               src = src_ptr + voice;
+               dst = dst_ptr + voice;
+               size = dst_size;
                if (pos >> SHIFT) {
-                       src_ptr += (pos >> SHIFT) * voices; pos &= MASK;
-                       for (voice = 0; voice < voices; ++voice) {
-                               S1[voice] = S2[voice];
-                               S2[voice] = src_ptr[voice];
-                       }
+                       src += ((pos >> SHIFT) - 1) * voices;
+                       pos &= MASK;
+                       S1 = S2;
+                       S2 = *src;
                }
-               
-               for (voice = 0; voice < voices; ++voice) {
-                       val = S1[voice] + ((S2[voice] - S1[voice]) * (signed int)pos) / BITS;
+               while (size-- > 0) {
+                       if (pos >> SHIFT) {
+                               src += (pos >> SHIFT) * voices;
+                               pos &= MASK;
+                               S1 = S2;
+                               S2 = *src;
+                       }
+                       val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
                        if (val < -32768)
                                val = -32768;
                        else if (val > 32767)
                                val = 32767;
-                       *dst_ptr++ = val;
+                       *dst = val;
+                       dst += voices;
+                       pos += data->pitch;
                }
-               
-               pos += data->pitch;
+               data->last_S1[voice] = S1;
+               data->last_S2[voice] = S2;
        }
        data->pos = pos;
 }